Technology – A Lab Aloft (International Space Station Research)

Space Station Espresso Cups: Strong Coffee Yields Stronger Science

In today’s A Lab Aloft, International Space Station researcher, Mark Weislogel, Ph.D., boils down why brews served in microgravity will percolate better science than coffee, thanks to the Space Cup.

*UPDATE: The Space Cup was named one of “The Most Cleverly Designed Objects of 2015” by WIRED Magazine!*

SA (European Space Agency) astronaut Samantha Cristoforetti - dressed in a Star Trek Voyager uniform - takes a sip of espresso from the new Capillary Beverage investigation, also known as Space Cup while looking out of the Cupola window. — European Space Agency (ESA) astronaut Samantha Cristoforetti – dressed in a Star Trek Voyager uniform – takes a sip of espresso from the new Capillary Beverage investigation, also known as Space Cup while looking out of the Cupola window. Credits: NASA

You may have heard the “caffeine buzz” around the Internet about the ISSpresso machine that recently launched to the International Space Station. It would be out of this world indeed to have a cup to go along with it. So we designed, fabricated, tested, and flight qualified one. In fact six such cups are now on the space station and ready for action. With real science backing the design, our microgravity coffee cup will do more than lift espresso to astronauts’ lips — it will also provide data on the passive movement of complex fluids as part of the Capillary Beverage investigation. The results will confirm and direct math models that help engineers exploit capillary fluid physics (capillary fluidics) to control how liquids move by designing containers specific to the task at hand. Whether getting the last drop of fuel for a rocket engine or delivering the perfect dose of medication to a patient, there are real Earth benefits behind the brew.

In 2008, astronauts aboard the International Space Station demonstrated the pouch method of drinking yesterday’s coffee and today’s coffee, while the Space Cup will serve the coffee of tomorrow — providing real science for fluid physics research. In the front, left to right, crew members Michael Finke and Chris Ferguson, with Eric Boe and Donald Pettit in the back. (NASA)

On Earth, gravity is responsible for making bubbles rise and liquids fall. Such mechanisms vanish in the weightless environment of orbiting spacecraft. In fact, in microgravity there is no concept notion of floating or sinking, or up or down. Other forces such as surface tension that are normally overwhelmed by gravity on Earth rise to dominate liquid behavior.

In a spacecraft, if the effects of surface tension are not understood, liquids (e.g., water, fuel) can be just about anywhere in the container that holds them. Similarly, the gas (e.g., oxygen, nitrogen) in such containers can freely range, too. You’re in for a challenge if you want to find where these fluids are and use them. Even if you just want to drink them. This is why in space you’ll only see astronauts drinking from bags with straws so that they can completely collapse the bag to assure the liquids come out. From a practical safety perspective, the bags also provide a level of containment.

When my laboratory heard of ESA astronaut Samantha Cristoforetti and the Italian Space Agency’s espresso machine investigation (ISSpresso) going to space, it got us thinking about that beautifully complex drink and how it would behave differently — especially whether the coffee would develop a crema or not. Currently, we don’t believe so because the bubbles that form during the espresso brew process won’t naturally rise to the surface due to absence of buoyancy in the microgravity environment. Other weaker forces often masked by gravity are present and will likely play an unearthly role in what happens, making the espresso fun to observe. It will be a different kind of fun altogether to get real science out of the process at the same time.

In a normal cup of espresso, carbon dioxide bubbles release and collect to form a crema. Some of the bubbles adhere to the walls of the cup, while the remainder rise and stratify due to their size in layers we refer to as foam. Steam rises above the surface of the crema in part condensing in an advancing front on the inside surfaces of the cup. The cup cools by natural convection and the aromatics waft at rates determined by buoyancy. These processes are completely induced by gravity!

When the influence of gravity is greatly reduced, as it is aboard orbiting spacecraft, not much of this stuff is going to happen. This will be unusual for the astronauts. Even the smell of the coffee diffusing through the crema is driven by natural convection currents in the air, which are absent in the microgravity environment. So the simple, every day fluid physics taking place in your daily coffee are highly dependent on gravity. From taste to smell, we anticipate what may even be a disappointing cup of coffee in space. But only the astronauts will know, and we will have to take their word for it in the hopes of one day trying this for ourselves.

Touching your lips to the rim of the Space Cup establishes a capillary connection allowing the drinker access to the entire contents. Sip-by-sip or in one big gulp, the cup’s contents may be imbibed somewhat normally in space, as on Earth. (A. Wollman, IRPI)

You can imagine how many variables are at play for the drinking experience from a human factors perspective, but gravity influences many of these, too. Sinus drainage, saliva migration, time aloft, and others are reasonable microgravity-related parameters affecting one’s response to the drinking experience in space. We designed the Space Cup with the central objective of delivering the liquid passively to the lip of the cup. To do this we exploit surface tension, wetting conditions, and the special geometry of the cup itself. We have yet to learn the human-cup interaction in microgravity. The cup design forces the drinker’s nose directly over the fluid contents. But since the aromatics do not rise, one might expect a rather concentrated dose upon the first whiff. Maybe this won’t be a big deal since astronauts report a reduced sense of smell while in space, due to somewhat clogged sinuses. This is presumably due to the headward fluid redistribution that occurs in spaceflight.

We were highly motivated to make the cup transparent so we could observe all of the fluid physics going on in the process. It may sound nerdy, but that’s what we do—we study microgravity fluid physics in hopes of designing more reliable fluid systems for future spacecraft, and more effective fluid systems for applications on Earth.

Touching your lips to the rim of the cup establishes a capillary connection, almost like the wicking of water through a paper towel, allowing the drinker access to the entire contents. My colleagues and I have been doing research aboard station for more than 10 years. During the course of hundreds and hundreds of experiments, we’ve been developing the mathematical predictive tools and computational tools for such passive capillary fluidic processes. Now we are in a place to develop designs for systems in space — systems with promises of high reliability because they perform their function passively, without moving parts. Examples include things like urine treatment and processing, and systems to close the water cycle helping to enable truly long duration crewed space exploration. These same tools also help us with fuel systems, cooling systems, water processing equipment for plant and animal habitats, and much more.

Perfecting these systems can also help us prevent disasters in orbit or on long-duration missions such as the journey to Mars. For example, the primary oxygen supply systems on many spacecraft use electrolysis. If the system gets a single air bubble lodged within its tubing, it can shut down until the bubble is found and removed. To get a sense of working with these types of systems in space, you need an understanding of capillary phenomena from studies, believe it or not, like Capillary Beverage.

The Space Cup’s specific design uses known geometry, gathered in prior International Space Station research, to direct fluids to the lip of the user. (Credit: M. Meyer, IRPI)

While fun, this study has plenty of design research behind it. Many of the aspects of our fluid physics research in microgravity are present in this simple cup demonstration — the effects of wetting, the effects of geometry, and the effects of fluid properties, especially surface tension. The results could provide information useful to engineers who design fuel tanks for commercial satellites, for instance. If you can find all your fuel, you can save costs and maximize the mission duration.

With this cup we can also study complex fluids that we have not previously addressed. For example, just adding sugar or milk to tea is expected to radically change the performance of the process of how the fluids move. We’ll approach this systematically aboard the space station. We’re starting off with water, then clear juice, then tea, tea with sugar, etc., including complex drinks like cocoa, a chocolate breakfast drink, and even a peach-mango smoothie. Undissolved solids, dissolved gasses, foams, free bubbles, surfactants, varying viscosities, temperature effects and more — all in little transparent 3D printed cups used by astronauts to drink on the space station. This progression from simple to complex beverages will give us a wealth of data — data which we aim to apply not just in space, but on Earth, too.

The astronaut(s) will set up the experiment near the galley, position the cup, camera, and lighting for orthogonal views (views at right angles), and a variety of experiments will be performed using the HD video as our quantitative data source. For example, when the astronaut fills the cup, the filing process is research. When the astronaut drains the cup, the draining is research. The static and dynamic interface shapes tell us everything we need to know, from wetting conditions to stability, to visco-capillary interaction. This is the exciting part for us! We see the profile of the interface, we watch particles and bubbles as flow tracers, we get velocities and volumetric drain rates, and all as functions of what the astronaut is doing — enjoying a cup of coffee! Astronaut Kjell Lindgren is planning to take up plenty of his own espresso during Expeditions 44/45. We have plenty to look forward to.

International Space Station Expedition 44/45 crew members Kjell Lindgren and Kimiya Yui enjoying food tasting at NASA’s Habitability and Environmental Factors Office in Houston. Lindgren plans to take his own espresso grounds with him into orbit to enjoy as part of the Capillary Beverage study. (NASA/Bill Stafford)

With this cup, most everything is taken care of passively by the shape of the cup. There isn’t a straight line in it. There are no moving parts. Wouldn’t it be nice if all the fluid systems on spacecraft worked like that? We know it would result in less worry on the ground. The simpler things are, the more robust their function and the less time is needed for maintenance.

Check out this video about our first version of a zero-g coffee cup.

What we are learning here is not just for space. All the design tools we are developing are applicable to small fluidic systems on Earth, too. For example, portable point-of-care medical diagnostic devices exploit capillary flow to passively move a very small sample of blood to any variety of regions on a testing chip. That makes it possible to diagnose infectious diseases in places where there is no power or where power is unreliable. It also reduces the time between sample collection and diagnosis and, therefore, initiation of treatment. We will report more on this connection in the future.

The next time you brew a cup of your favorite coffee, imagine what it might be like to take a sip from the Capillary Beverage cup aboard the International Space Station while watching the Earth go by. Then consider the fluids research off the Earth, that can make a difference right here on the Earth.

Mark Weislogel, Ph.D. (Portland State University)

Mark Weislogel, Ph.D., is senior scientist and vice president of IRPI LLC and professor Mechanical Engineering at Portland State University. He was founded in microgravity fluid physics while employed at NASA’s Glenn Research Center. Whether in the private sector or academia, Weislogel has since continued to make extensive use of NASA ground-based low-gravity facilities and has completed investigations aboard space shuttles, the Russian Mir Space Station, and the International Space Station. He led the design of the Dryden Drop Tower, which has conducted over 4,000 drop tests and continue at a rate of over 1,000/year. Current efforts are directed to research, development, and delivery of advanced fluid systems for spacecraft.

2014 Retrospective a Look Forward as the Space Station Comes into its Own

In today’s A Lab Aloft International Space Station Chief Scientist Julie Robinson, Ph.D., looks back on 2014 to highlight some of the year’s milestones and research achievements.

As I take a moment to reflect on the accomplishments of the past 12 months, I can’t help but think of how they relate to where we’re going next with the International Space Station. From the crew capabilities to research goals, from NASA’s plans for continued exploration to the benefits for humanity from station studies, there are some key areas that stand out from 2014.

Expedition 41 crew portrait on the International Space Station. From left: ESA astronaut Alexander Gerst, Roscosmos cosmonauts Elena Serova, Maxim Suraev and Alexander Samokutyaev, and NASA astronauts Reid Wiseman and Barry Wilmore. (NASA)

During the last year there has been so much demand for research on the space station—including investigations that require crew time—planners really have had to push the schedule. We deferred some preventative maintenance, scaling back on some filter changes, for instance, to adjust operations for increased crew time for research. That’s allowed us to get as much as 47 hours a week averaged in a six-month period. This number is the total for the three U.S. astronauts, rather than the original standard of 35 hours for science. When you think about it, that’s almost half again as much research as the designed schedule.

This is a great performance of balancing time aboard station, though we won’t always be able to hold to that. This is why we still need to go to seven crew members. The crew dedicating time to tend to investigations helps us to optimize the research coming out of space station, as well. Currently we house six crew members in orbit aboard the space station, and some of you may know that this is one person short of the craft’s design to sleep seven. This is because our Soyuz “lifeboat” can only return six crew members in an emergency. The advent of commercial crew will allow us to expand by that extra crew member, as the new vehicles can ferry four. This is a future goal that we all look forward to: a full house.

The crew was particularly busy during the latter part of 2014 with a huge new capability for biological research using model animals. This also was driven by user demand to launch rodents—meaning mice and rats, though so far we’re starting with mice on the space station. We now have a system that can launch rodents aboard the SpaceX Dragon vehicle. The animals can live aboard station for a long period of time in special habitats, and then either be processed on orbit or eventually returned live. This system was important to get online this year, because we had a large number of users in medical research and pharmaceuticals interested in using space station as a test bed for their studies.

NASA astronaut Butch Wilmore setting up the Rodent Reseach-1 Hardware in the Microgravity Science Glovebox (MSG) aboard the International Space Station. (NASA)

There are many discoveries that have affected human health that were dependent on the use of animals as what we call “model organisms,” from the discovery of insulin to the that of tamoxifen to treat breast cancer to kidney transplants. This doesn’t mean these organisms are going to grace the cover of a magazine, but rather that they provide a model for humans to help us understand disease processes. By watching how they respond to research, we can in turn learn how to fight those diseases.

The use of model organisms in laboratories on Earth and aboard the International Space Station can lead to insights for researchers into human health. (NASA/Julie Robinson)

Having the ability to fly mice to space for long-duration studies is a huge advance. Fulfilling this capability was our response to the Decadal Survey recommendations of the National Academy of Sciences. We have years of research already lined up hoping to get access to these mice. To optimize the potential for discovery, we combine as many experiments together on this precious resource as possible.

This is an exciting area of study, as just a handful of mice have flown in the past—both on space station assembly flights and one flight in a system called mice drawer system. Even so, those findings account for a significant number of our highest profile publications from space station research. With access twice per year, we now have this type of study as a routine capability. This means we can expect to see a huge ramp-up in high-impact research in biomedical areas.

Another big change this year has been the space station maturing as a platform for Earth science. My colleagues in Earth sciences at NASA have called this the year of the Earth, because they’ve had five related instruments go into space this year. That’s a record, and two of these are on the space station, a first!

Artist's rendering of NASA's ISS-RapidScat instrument (inset), which launched to the International Space Station in 2014 to measure ocean surface wind speed and direction and help improve weather forecasts, including hurricane monitoring. It wasinstalled on the end of the Columbus laboratory. NASA/JPL-Caltech/Johnson Space Center — Artist’s rendering of NASA’s ISS-RapidScat instrument (inset), which launched to the International Space Station in 2014 to measure ocean surface wind speed and direction and help improve weather forecasts, including hurricane monitoring. It was installed on the end of the Columbus laboratory. NASA/JPL-Caltech/Johnson Space Center

Moving forward we’re going to see a couple instruments a year go up until the space station’s current external sites are primarily full, likely in 2017. We now need to study whether to grow our capabilities to support more Earth sciences instruments, as well as astrophysics and heliophysics studies.

It’s really thrilling to see these initial instruments come to station and begin operations right off the bat. The first of these, ISS-RapidScat, was bringing hurricane data home within three hours—this was less than a week after installation. The instrument measured the sea-surface winds and was used to look at Typhoon Vongfong in Japan. How quickly scientists can use these data and incorporate findings into use for us on the ground can provide real benefits. The results can give valuable information that people need to know to protect their lives and property, making it an important advance to have available aboard station.

Next is the Cloud-Aerosol Transport System (CATS), an imager that looks at clouds and aerosols for climate research. CATS will be followed by a number of instruments that are either brand new to science or that fill a gap from similar satellites to provide cross calibration. Our understanding of the Earth is going to improve thanks to the research from all of these instruments.

Supertyphoon Vongfong as seen by the crew of the International Space Station on Oct. 9, 2014. (NASA) — Super typhoon Vongfong as seen by the crew of the International Space Station on Oct. 9, 2014. (NASA)

One of the areas that congress has encouraged us to pursue is the development of commercial applications and commercial research on the space station. To this end, they declared the space station U.S. segment a national laboratory in 2005. In 2011 we selected CASIS, the Center for Advancement of Science in Space, to manage that national lab side for use by researchers that are not funded by NASA. These scientists may be funded by other government agencies or the private sector or nonprofit organizations.

This year CASIS grew substantially with the advent of their ARK-1 and ARK-2 suites of investigations aboard station. Also in 2014, the first National Institutes of Health (NIH) investigator of the space station national lab era launched her immunology research study. There are other NIH studies to come, including one that looks at bone loss. CASIS also brought large initiatives in protein crystal growth, Earth sciences, stem cells and materials science to continue to advance commercial research aboard the space station.

I recently spoke with Brian Talbot, marketing and communications director with CASIS, and he shared his thoughts with me on the accomplishments of the organization for the past year. “The continued growth of CASIS as an organization in 2014 speaks to the limitless opportunities commercial and academic researchers see aboard the space station. Through funded solicitations in proven areas of space-based research to innovative and non-traditional commercial users, CASIS is moving ever closer towards its goal of fully utilizing of the national lab for Earth-benefit inquiry.”

When I talked about crew time, you may have noticed that it was broken down by U.S. and Russian segments and crew members. While this division is useful for tracking purposes, it’s important to mention how we are blurring those boundaries. This international laboratory brings collaborations together through research that transcend relations on the ground. The space station exemplifies a global partnership at its best.

One thing that has driven us to continue advancing our partnership is the announcement of the joint one-year expedition. Since the 2013 announcement, we have made advances in finalizing our research goals in preparation for the 2015 launch. This extended expedition will have an astronaut and a cosmonaut both stay aboard the space station for 12 months, instead of the current six-month standard. It’s been decades since astronauts were in space that long. With the leaps in our medical technology, the one-year stay will help us to better understand what happens to the human body on long-duration flights. These studies also may help answer related concerns for health here on Earth.

Selected crew members for the one-year mission aboard the International Space Station, U.S. Astronaut Scott Kelly (pictured left) and Russian Cosmonaut Mikhail Kornienko (pictured right). (NASA)

I’m really excited about how that international collaboration across all of our partners has evolved. We’re combining more investigations, we’re releasing open data for the entire global scientific community to work with and we’re joining crew member resources to optimize all of these activities. Whether it’s microbial sampling, taking care of plants or making specific observations of the human body, our crew members are working together on what is truly an international station in space.

Early this year, John Holdren, the director of the Office of Science and Technology Policy for the Obama administration, announced their support of extending the space station to 2024. We have worked through the impacts that this has for space station research and this extension gives us 90 percent more external research and close to 50 percent more pressurized research—those studies taking place in the cabin. 2024 is very important to what we can achieve with this global microgravity resource of the space station.

When we have scientists already in line wanting to do investigations, having more time to get those studies done and even to do follow-on research opens up the discovery potential. This also provides more time for research markets to develop independently. Just like on the ground, when someone wants to study a certain area, they contract a lab to do the experiments. Someday, when space station is gone, we want scientists to have continued access through this emerging market of microgravity research in space. This longer duration for station to remain as a platform helps to open up those opportunities for researchers around the world. This is the world’s chance to continue the mission of discovery off the Earth for the Earth.

Julie A. Robinson, Ph.D. International Space Station Chief Scientist

Julie A. Robinson, Ph.D., is NASA’s International Space Station Chief Scientist, representing all space station research and scientific disciplines. Robinson provides recommendations regarding research on the space station to NASA Headquarters. Her background is interdisciplinary in the physical and biological sciences. Robinson’s professional experience includes research activities in a variety of fields, such as virology, analytical chemistry, genetics, statistics, field biology, and remote sensing. She has authored more than 50 scientific publications and earned a Bachelor of Science in Chemistry and a Bachelor of Science in Biology from Utah State University, as well as a Doctor of Philosophy in Ecology, Evolution and Conservation Biology from the University of Nevada Reno.

AMS Amassing Answers to the Questions of the Universe

In today’s A Lab Aloft our guest blogger is Trent Martin, the NASA project manager for the Alpha Magnetic Spectrometer instrument. Martin shares the challenges and excitement of seeking to unravel the mysteries of the universe.

Can a single data point make a difference? When speaking of the collected billions of data points since the inception of the Alpha Magnetic Spectrometer-02 (AMS-02) to the International Space Station (ISS), the answer is yes. Every data point leads us closer to unveiling the answers to the questions of the universe.

A handful of those unique data points were the topic of the keynote speech delivered by AMS principal investigator Professor Samuel Ting at this year’s ISS Research and Development Conference in Chicago. Approximately 90 percent of the universe is not visible and is called dark matter. Collisions of “ordinary” cosmic rays produce positrons. Collisions of dark matter will produce additional positrons. This excess of positrons has been seen in the AMS data. While more data is needed, this specific handful of points tells us something we didn’t know before about our universe. It adds to our current knowledge and guides us on our path to answers in the areas of dark matter and more.

Professor Samuel Ting answers questions while attending the 2014 International Space station Research and Development Conference in Chicago, where he was a keynote speaker on the topic of the Alpha Magnetic Spectrometer. (NASA/Bill Hubscher)

In May, 2011 as the space shuttle Endeavor sat on the pad ready to launch the AMS-02 to the space station, it carried the hopes and dreams of 600 physicists, engineers and technicians from 60 institutes in 16 countries who had worked for nearly 1.5 decades to build the most sophisticated magnetic spectrometer ever to be put into space. Led by Ting, a Nobel Laureate from the Massachusetts Institute of Technology, the detector is designed to cull through galactic cosmic rays searching for the origins of the universe, evidence of dark matter, evidence of naturally occurring anti-matter and other cosmic phenomena.

In the words of Ting, “the most exciting objective of AMS is to probe the unknown; to search for phenomena which exist in nature that we have not yet imagined nor had the tools to discover.” AMS-02 provides that set of tools.

The Alpha Magnetic Spectrometer-02 (AMS-02) operating aboard the International Space Station. (NASA)

It is exciting to have the chance to continue to collect data to close the gap on these types of questions. The AMS-02 will run aboard station for the next decade—a timeline granted by the station extension to 2024, but also thanks to a design change just prior to the launch to the space station. This was at the time of an earlier station extension to 2020, at which point the original cryogenic magnet was swapped for a permanent magnet. Had we kept the original magnet, the AMS-02’s life expectancy for operations on orbit would already be at a close—and we’d be left with questions unanswered. Instead, the final selection of a permanent magnet enabled our continued quest towards discovery today.

Let’s take a closer look at how AMS-02 works to help us seek those answers. If you asked a high-energy experimental physicist to provide a wish list of every instrument they would like to see on some theoretical detector, they would likely provide a list that is identical to the six instruments that make up the AMS-02. Since the detectors are so complex and include over 300,000 data channels, providing for easily replaceable systems in space was nearly impossible. Instead, the systems were designed and built with a significant amount of redundancy. Multiple detectors measure charge, momentum, and energy of a passing particle. Although each detector measures in a different way, it provides us redundant and confirming measurements. The electronics for the detectors are also redundant. In most cases, the electronic systems have four-fold redundancy. This makes for a reasonably secure fail-safe, most would agree.

Operations on the station began within hours of the AMS-02 installation on the S3 truss. Since May 2011, there has been very little time when AMS-02 was not collecting data. The amount of information has been somewhat unexpected. AMS-02 has measured more than 52,000,000,000 particles. In fact, we measure at a rate of 16,000,000,000 particles per year. We were expecting more like 11 billion particles per year. This improved rate of return means more data points in each communication for ground teams to analyze.

In addition to the external instrument, which is the largest payload aboard station, the AMS-02 employs a laptop that is dedicated to the instrument’s operations from the interior of the orbiting laboratory. This internal system acts as a crew interface to AMS-02 and provides a backup system in the event of a long-term loss of data from the space station to the ground. This is an important capability for our search for antimatter because it only takes one of the billions of events to see an antimatter particle.

View of Don Pettit, Expedition 30 Flight Engineer, holding the Alpha Magnetic Spectrometer (AMS) laptop in the U.S. Laboratory of the International Space Station. (NASA) — View of Don Pettit, Expedition 30 Flight Engineer, holding the Alpha Magnetic Spectrometer (AMS-02) laptop in the U.S. Laboratory of the International Space Station. (NASA)

The search for anti-matter is actually quite challenging. I think of it like this, during the spring in Houston, there are many rain showers. If we assume it is a very rainy day in the large city of Houston, it would be like someone asking you to look at all of those clear rain drops and find one drop that is colored red! As we look at the billions of data points, we are seeking a drop in a rainstorm of information.

A view of the Alpha Magnetic Spectrometer-02 (AMS-02) as mounted aboard the exterior of the International Space Station. (NASA)

The AMS-02 science data points are stored on NASA computers as soon as the information reaches the ground at the Marshall Space Flight Center in Huntsville, Alabama. It is stored again as soon as it reaches Geneva. Teams of scientists work daily to analyze the data coming from the AMS-02. Typically these teams are broken into two groups to ensure that the analysis is independently analyzed. The teams meet about once per month to go through their results, work on papers, and identify new areas of interest. AMS-02 publications can be found here.

Thanks to the extremely high data rate and the precision of the AMS-02 detectors, the data is providing significantly improved tolerance bands on the measured data when compared to other detectors. In the past hundred years, measurements of charged cosmic rays by balloons and satellites have typically contained approximately 30 percent uncertainty. AMS-02 will provide cosmic ray information with closer to one percent uncertainty.

Nobel Laureate Samuel Ting, principal investigator for the Alpha Magnetic Spectrometer, speaks about the first published results of AMS-02 during a 2013 press conference at NASA’s Johnson Space Center in Houston. (NASA/James Blair)

There is a lot of excitement that surrounds the findings from this instrument. The first paper published by AMS-02 was published in Physical Review Letters. The paper was highlighted in a Viewpoint appearing in the April 2013 issue of Physics. Being chosen for Viewpoint is a very selective process. According to the editor in chief of American Physical Society, “The APS published a total of about 18,000 articles last year, but only around 100 Viewpoints will appear each year. This places your paper in an elite subset of our very best papers.”

Based on the data coming from AMS-02, the space station has become a unique platform for precision physics research. During this orbiting laboratory’s lifetime, we expect to obtain 300 billion events. It is my hope and belief that somewhere buried in those 300 billion events we will find a better understanding of the origins of the universe.

Trent Martin, NASA project manager for the Alpha Magnetic Spectrometer at Johnson Space Center in Houston. (NASA/Robert Markowitz)

Trent Martin is currently the associate director of engineering for advanced development at NASA’s Johnson Space Center in Houston, in addition to serving as the AMS NASA project manager. Martin has a bachelor’s degree in Aerospace Engineering from the University of Texas and an MBA from the University of Houston at Clear Lake. He has worked at Johnson since 1995.

International Space Station’s Place in the Global POV of the World Science Festival

In today’s A Lab Aloft, guest blogger Tara Ruttley, Ph.D., NASA International Space Station associate program scientist, shares her experience from the 2014 World Science Festival.

I think I’m finally recovering from the amazing whirlwind that was the World Science Festival. From May 28 to 31, NASA had the exciting opportunity to participate in the event held in New York City. The festival, created by physicist Brian Greene, is an annual city-wide series of events that include smaller panels, interactives, demonstrations and presentations, all with the goal of sharing fascinating and cutting-edge science with the public.

Kids and adults alike got a kick out of the NASA mobile exhibit during the World Science Festival. (Tara Ruttley)

My role was to coordinate and present the science happening on the International Space Station (ISS) with attendees in a World Science Festival style. This means “Go Big!” The kinds of exchanges that happen in environments like this have dual benefits for the agency. The public gets informed about the work that NASA does—and we really hope they get inspired and motivated—and NASA gets to learn just what the public thinks about us, for better or worse.

When given the challenge last fall to prepare for NASA’s participation in the festival, the first thing I did was identify some of the most passionate, excited space station scientists. I then invited them to showcase their work among the many World Science Festival activities sprinkled throughout the week in June. Of course our very own International Space Station Program Science Office was ready to share our investigations with the masses. There were so many great researchers and experiments that came to mind that I wanted to share with the visitors to the event.

Considering the array of schedule constraints and correct alignment of the cosmos, I was finally able to put a team together to represent space station research at the event. I recruited space station fluid physicist Mark Weislogel from Portland State University, who talked with audiences about his wild findings on fluid behavior in microgravity. I also asked aerospace engineer Nancy Hall, who brought her drop tower out for public interaction from NASA’s Glenn Research Center in Ohio. Then I also recruited Alvar Saenz-Otero and his award-winning MIT SPHERES team, who had demonstration units used for the Zero Robotics: ISS Programing Challenge for the public to try out.

At left, Alvar Saenz-Otero, Ph.D., and his team present the Zero Robotics: International Space Station Programing Challenge to the public at the World Science Festival in New York. (Tara Ruttley)

From NASA’s Human Research Program, Andrea Dunn attended and demonstrated the space station’s new Force Shoes investigation. Team members from NASA’s Human Research Program based at the agency’s Johnson Space Center in Houston showed visitors how liquid recycling happens in space. They explained the importance of hydration for astronauts and those of us here on Earth.

Speaking of NASA astronauts, Sandy Magnus, Mike Massimino, and Mike Hopkins made appearances to talk about their space science experience with eager listeners. The Associate Administrator for the Science Mission Directorate at NASA Headquarters, John Grunsfeld, also joined in to discuss the actual science behind the movie “Gravity.”

NASA astronaut Mike Massimino meets a young fan at the 2014 World Science Festival. (World Science Festival)

This was quite a unique series of events with an assortment of participants representing the research we have done, continue to do and plan to do for the next decade aboard the space station. As we scientists were celebrated for our love of discovery—BONUS!—we got to share that enthusiasm with a massive crowd. For self-proclaimed science geeks like me, it was utopia!

For months leading up to the big week, our space station teams were hard at work to deck out the NASA mobile exhibit to look like the inside of the space station. We also included displays of some of the most stunning science footage ever taken aboard the station. We really wanted the public to experience what the astronauts feel in orbit—Ok, I admit the addition of a microgravity component itself would have been really cool, if we could create such a thing. I believe we achieved our goal of conveying the importance of the types of science we do on station to advance both human exploration of space and to improve our lives on Earth.

A young visitor to the NASA mobile exhibit interacts with a display of a research rack as it would appear aboard the International Space Station. (Tara Ruttley)

Once inside the exhibit, NASA scientists were on hand to answer questions from visitors like: What happens when we light fires in space? Why do astronauts lose bone mass at a rate equivalent to Earth-based osteoporosis? Why do we study fluid behaviors in space? Do fish get confused when swimming in space?

All of these questions can be answered along the same theme: we’re learning about new behaviors, relationships and processes we’ve never even discovered before on Earth. In so doing, we apply that knowledge to existing systems on Earth and in space to constantly improve our very existence. During the week of the World Science Festival, we must have answered hundreds of questions as we interacted with upwards of 150,000 people interested in space station science!

And, inevitably, yes, we did get the common question we’ve come to expect: how do you go to the bathroom in space? The NASA exhibit even came prepared with a demonstration unit of the Waste Management Center (WMC)—that is, a space potty! For display purposes only, of course.

A visitor to the NASA exhibit at the World Science Festival experiences the Waste Management Center (WCS) “potty” on display during the event. (Tara Ruttley)

Potty talk aside, the public cares about the science we conduct on the space station. They ask many of the common questions surrounding science in space, and they also ask new questions, which leads us all to think about “what if…” ideas that we may just try out in space one day. One thing’s for certain, when we support science outreach events like these, the people we meet usually have as big an impact on us as we do on them. And for that, many thanks for your inspiration!

1023637main_Tara Ruttley 2011.jpg — Tara Ruttley, Ph.D. (NASA)

Tara Ruttley, Ph.D., is associate program scientist for the International Space Station at NASA’s Johnson Space Center in Houston. Ruttley previously served as the lead flight hardware engineer for the ISS Health Maintenance System and later for the ISS Human Research Facility. She has a Bachelor of Science in biology and a Master of Science in mechanical engineering from Colorado State University and a doctorate in neuroscience from the University of Texas Medical Branch. Ruttley has authored publications ranging from hardware design to neurological science and holds a U.S. utility patent.

A PECASE for Space and Skeletal Biology Research

In today’s A Lab Aloft, Joshua S. Alwood, Ph.D., shares his postdoctoral research into the impact of microgravity and ionizing radiation exposure on bone health – work that led to his receiving the 2012 Presidential Early Career Award for Scientists and Engineers.

I am honored to be a recipient of a 2012 Presidential Early Career Award for Scientists and Engineers (PECASE). This award is based on the cumulative body of work achieved during my postdoctoral fellowship at NASA’s Ames Research Center in Moffett Field, Calif., while working with my advisor Ruth Globus, Ph.D. and on my contribution to experiments that flew on International Space Station assembly flights STS-131 and STS-135 with collaborator Eduardo Almeida, Ph.D.

Ellen Stofan, Ph.D., NASA's Chief Scientist presents Josh Alwood, Ph.D., the 2012 Presidential Early Career Award for Scientists and Engineers (PECASE) award. (NASA/Joel Kowsky) — Ellen Stofan, Ph.D., NASA’s chief scientist presents Josh Alwood, Ph.D., the 2012 Presidential Early Career Award for Scientists and Engineers (PECASE) award. (NASA/Joel Kowsky)

The big question motivating our studies is, how does spaceflight cause bone loss in astronauts? While weightless, astronauts lose about one percent bone mineral density per month. To put this into context, this is about 10 times faster than osteoporosis typically progresses on Earth. The longer the mission, particularly outside Earth’s protective magnetic fields, the greater the doses of ionizing radiation astronauts will accumulate, which may also negatively impact the skeleton.

NASA astronauts Tracy Caldwell, STS-118 mission specialist, and Charles Hobaugh, pilot, working with the Commercial Biomedical Testing Module 2 investigation aboard space shuttle Endeavour. (NASA)

In our ground-based research, we asked the following questions: how do the conditions of simulated weightlessness and ionizing radiation exposure affect the skeleton, and are the results any different when these conditions are combined? Our results suggest that each condition causes bone loss on its own, though at differing rates and severity. Together, weightlessness and radiation exposure cause bone loss to worsen beyond either treatment alone. These results have to do with the behavior of different types of bone cells. Combined, the balance of bone formation and bone resorption—breaking down—define a normal process called bone remodeling, which the body uses to maintain a healthy skeletal structure throughout life.

Following radiation exposure, there is a rapid stimulation of bone resorption—this can lead to a net loss of skeletal tissue caused by a specific cell called an osteoclast. We quantify this by measuring the number of osteoclast cells on the surface on the bone and their level of activity through specific proteins secreted into circulation. At the tissue level, we use X-ray imaging and computed tomography to build and quantify three-dimensional models of the skeleton. This rapid resorption is concentrated, yet it appears to be short-lived. At the doses we’ve investigated, it doesn’t get worse after the initial burst.

X-rays of mouse bones from the CBTM study showing a ground control (left), as treated with Osteoprotegerin in microgravity (middle), and with no drug treatment during spaceflight (right). (L. Stodieck, Bioserve and T. Bateman, University of North Carolina) — X-rays of mouse bones from the Commercial Biomedical Testing Module (CBTM) study showing a ground control (left), as treated with Osteoprotegerin in microgravity (middle), and with no drug treatment during spaceflight (right). (L. Stodieck, Bioserve and T. Bateman, University of North Carolina)

In contrast, structural changes caused by simulated weightlessness gradually appear. Simulated weightlessness activates bone resorption by the osteoclasts and additionally reduces bone formation by inhibiting a second cell type called an osteoblast.

Exposure to space radiation affects osteoblasts as well. Our research shows that at the estimated doses potentially accumulated over a three-year Mars mission, long-lasting effects to the osteoblast-lineage cells occur. This may result in abnormal bone remodeling in the long-term. To this end, we determined that spongy bone—found on the inside of some bones—recovered less efficiently following radiation exposure vs. recovery from simulated microgravity.

Osteocyte lacunae from the ground-based control (left) and after 15 days of spaceflight (right). Space-flown lacunae appear larger, indicative of osteocytic remodeling. (Blaber, et al, PLoS One, 2013)

The second component of the PECASE acknowledges my work with the Biospecimen Sharing Program for shuttle flight STS-131. Along with Almeida, the project investigator, I used a new application of a high-resolution (30 nanometer) X-ray transmission microscope at the SLAC National Accelerator Laboratory to analyze bone health following 15 days of spaceflight.

We scanned the bones and processed the images for three-dimensional tomographic analyses. As a result, we were able to quantify changes in the bone’s osteocyte cells. In a unique mechanism of bone loss, osteocytes actively remodel and enlarge their living spaces, known as lacunae, in response to spaceflight. This is an additional mode of bone resorption that occurs during spaceflight at the bone’s surface.

My research employs a basic biology approach with the overriding motivation to enable human exploration of space. In other words, the goal is to expand the envelope of mission durations, the distance from Earth that missions can access, and to mitigate the skeletal consequences following radiation exposure for astronauts. My colleagues and I use a basic approach to uncover the cellular and molecular mechanisms that underlie skeletal changes in the space environment. Eventually we can use this knowledge to develop countermeasures to better manage astronaut skeletal health.

On Earth, this research has applications towards improving our knowledge of bone diseases such as osteoporosis. It may also help people living sedentary lifestyles, providing positive impacts to their health. The sedentary environment is somewhat similar to weightlessness. The take-home message: use your skeleton or lose it. The ability to work on advancing an area of biology that may help humans both in space and on the ground is truly its own reward.

Fluorescent image of femur diaphysis from ground control placebo treated mouse, indicating greatly decreased bone formation. (NASA)

I was inspired to enter this area of research from childhood experiences. I grew up in Florida and witnessed space shuttle launches in my front yard. This really captivated my attention towards space. As I got older, I learned about the skeleton and how it is a living structure that adapts to its mechanical environment. For example, joggers experience forces equivalent to about three times their body weight. Those two factors overlapped in my extracurricular readings on astronauts and the changes in their bodies during weightlessness. That connection propelled me to focus on science and engineering in my education, and further to study the skeleton. I am driven to continually learn new things, which prompted me to enter graduate school and become an independent researcher.

NASA astronaut Nicole Stott, STS-133 mission specialist, using a camcorder to record Mouse Immunology-2 investigation in one of the space shuttle Discovery’s middeck lockers. (NASA)

Although I do not have an immediate investigation going to the space station, I am applying for opportunities through NASA’s Space Biology Project. It’s an exciting time to be part of NASA’s research program. In the meantime, I continue to develop hypotheses worth studying aboard the space station and generating preliminary evidence while working in my lab on the ground. My goal is to eventually take my science into orbit or beyond.

The work cited in this PECASE Award was made possible by key funding organizations, including NASA Space Biology; grants to Globus from the National Space Biomedicine Research Institute; the U.S. Department of Energy and the NASA Space Radiation Project Element; and grants to Almeida from the NASA Bion-M1 Biospecimen Sharing Program and the National Institutes of Health / National Institute of Biomedical Imaging and Bioengineering.

Josh Alwood in the Bone and Signaling Lab at NASA's Ames Research Center. (NASA /Dominic Hart) — Josh Alwood in the Bone and Signaling Laboratory at NASA’s Ames Research Center in Moffett Field, Calif. (NASA /Dominic Hart)

Joshua S. Alwood, Ph.D., is a senior scientist with CSS-Dynamac working at the Bone and Signaling Lab at NASA’s Ames Research Center in Moffett Field, Calif. Alwood earned his Ph.D. in Aeronautics and Astronautics from Stanford University, as well B.S. degrees in Physics and Astronomy from the University of Florida.

Crystallizing Opportunities With Space Station Research

In today’s A Lab Aloft, Dr. Larry DeLucas, a primary investigator for International Space Station studies on protein crystal growth in microgravity, explains the importance of such investigations and how they can lead to human health benefits.

We have many proteins in our body, but nobody knows just how many. Consider that the human genome project is more than 20,000 protein-coding genes, and many of these genes or portions of those genes combine with others to create new proteins. The human body could have anywhere from a half million to as many as two million proteins—we’re not sure. What we do know, is that these proteins control aspects of human health and understanding them is an important beginning step in developing and improving treatments for diseases and much more.

A protein crystal is a specific protein repeated over and over a hundred thousand times or more in a perfect lattice. Like a row of bricks on a wall, but in three dimensions. The more perfectly aligned that row of bricks or the protein in the crystal, the more we can learn of its nature. Today there are more than 50,000 proteins that have been crystallized and the structures of the three-dimensional proteins comprising these crystals have been determined. Unfortunately many important proteins that we would like to know the three-dimensional structures for have either resisted crystallization or have yielded crystals of such inferior quality that their structures cannot be determined.

Crystals of insulin grown in space (left) helped scientists determine the vital enzyme's structure with much higher resolution than possible with Earth-grown crystals (right). (NASA) — Crystals of insulin grown in space (left) helped scientists determine the vital enzyme’s structure with much higher resolution than possible with Earth-grown crystals (right). (NASA)

Once we have a usable protein crystal—one that is large and perfect enough to examine—the primary technique we use to determine the protein molecular structures is x-ray crystallography. When we expose protein crystals to an x-ray beam, we get what’s called constructive interference. This is where the diffracted x-rays coming from the electrons around each atom and each protein come together, providing a more intense diffraction spot. We collect hundreds of thousands, sometimes millions of diffraction spots for a protein. The more perfectly ordered the individual protein molecules are within the crystals, the more intense these spots. The higher signal to noise ratio in these strong spots creates an improved resolution of the structure, allowing us to map the crystal in detail.

Well-ordered protein crystal x-ray diffractions create sharp patterns of scattered light on film. Researchers can use a computer to generate a model of a protein molecule using patterns like this. (NASA)

Using computers, we take those diffraction spots and mathematically determine the structure of where every atom is in the protein. For example, in most protein structures we can’t even see the hydrogen atoms. We guess where they are because we know the length of a hydrogen bond. So if we see a nitrogen atom from an amino acid that we know has a hydrogen linked to it, and then at a hydrogen-bonding distance away we see an oxygen atom, then we can make an educated guess that the hydrogen is pointed towards that oxygen atom, so we position it there.

While we can grow high-resolution crystals both in space and on the ground, those grown in space are often more perfectly formed. That’s the main advantage and reason we’ve gone to space for these studies. In many cases where we could not see hydrogen crystals on the ground, we then flew that protein crystal in space and let them grow in microgravity. Because of the resulting improved order of the molecules laying down in the crystal lattice, we were able to actually see the hydrogen atoms. Usually to see the hydrogen atoms, you are talking about getting down to a resolution of one angstrom, which is not easy to do—it would take 10 million angstroms to equal one millimeter!

Another example of protein crystals grown in space (right), which are larger and more perfect than those grown on the ground (left). (JAXA)

We also can look at bacteria and virus protein structures to identify how to target those proteins with drugs. Having this information is very important to pharmaceutical companies and universities. That structure provides a road map that is critical for the understanding of the life cycle of the bacteria or virus.

We’ve only done a fraction of the more important complex protein structures–I’m referring to membrane proteins and protein-protein complexes. Protein complexes are often composed of two, three or more proteins that interact together to form new macromolecular complexes that are often important in terms of disease and drug development. Membrane proteins are the targets for about 55 percent of the drugs on the market today. Scientists have determined the three-dimensional structures for less than 300 membrane protein structures thus far. However, there remain thousands more for which the structures would help scientists understand their important roles in chronic and infectious diseases.

When we see a specific region in a protein and we know exactly where every atom is, chemists can design drugs that will interact in those regions. We can take some of the drugs they design that work, but maybe not as well as we would like. We then grow new crystals of the protein with the drug attached to the protein to see exactly how it’s bound to the protein. That lets other scientists—modelers—determine very clearly how the drug interacts with the protein, information that enables them to design new, more effective compounds. This whole process is called structure-based drug design.

The International Space Station provides a unique environment where we can improve the quality of protein crystals. During the days of protein crystallization studies on the space shuttle, one of the most frustrating aspects of the microgravity experiments was the length of time it took to produce a usable crystal. This is actually part of why space-developed crystals are better—they grow much more slowly. On the shuttle you only had 10-12 days for a study, but aboard the space station you have as long as you need.

As an astronaut and scientist, I personally flew a record 14-day flight in 1992 where we studied 31 proteins. I was looking at results and planning to set up new experiments, changing the chemical conditions to optimize the crystallization. The rule for my sample selection was that the proteins had to nucleate—that means to begin to grow a crystal—and grow to full size in three days. Once I got up there, however, by the third day nothing had nucleated. I was worried, but then on the fourth day I could see little sparkles where crystals had started to grow in about half of the proteins. By mission end I was really only able to optimize the crystal growth for six of the proteins. How much longer it takes a crystal to nucleate and grow to full size was a dramatic discovery.

Astronaut Larry DeLucas, payload specialist, handles a Protein Crystal Growth (PCG) sample at the multipurpose glovebox aboard the Earth-orbiting space shuttle Columbia. (NASA)

With constant access to a microgravity lab, such as the space station, I am confident that we can improve the quality of any crystal. With protein crystals it is important to note that just because we get a better structure with higher resolution, it doesn’t at all mean it’s going to lead to a drug.

The ability to grow good crystals typically involves a great deal of preparation on the ground where we first express and purify and grow the initial crystals. But if space can give you higher resolution, there’s no drug discovery program that’s going to take a lower resolution option. From the time you determine that structure and chemists work with it, the typical time frame to develop a drug is 15 to 20 years and the cost is around a billion dollars. Identifying the structure of the protein crystal is only the first step. Many times even with the structure a project goes nowhere because the drugs they develop end up being unusable. There are so many aspects to drug discovery beyond the opening act of structure mapping.

If crystals and the structure of a target protein are available, pharmaceutical and biotech companies certainly prefer to use that structure to help guide the drug discovery. After the first 18 months they’ve developed the drug candidates, they may not need to use the crystal structure again for say 10 years. During that time they are doing clinical trials and pharmacology. The majority of the money it takes to get a drug approved by the FDA is after the initial phase. If you break down what they say is about a billion dollars to develop a drug, the portion needed to get the structure up front will range from half to two million dollars—a small fraction of the whole process.

View of Expedition 28 Flight Engineer Satoshi Furukawa with the JAXA Protein Crystal Growth (PCG) investigation aboard the International Space Station Japanese Experiment Module (JEM). (NASA)

For the upcoming Comprehensive Evaluation of Microgravity Protein Crystallization investigation we focused on two things. First, we selected proteins that are of high value based on their biology. Having this information of their structure can lead to new information about structural biology—how proteins work in our body. The other major requirement for the candidates for selection was that the proteins had to have already been crystallized on Earth, but the Earth-grown crystals were not of good quality.

We are flying 100 proteins to the space station on SpaceX-3, currently scheduled for March 2014. Twenty-two of these are membrane proteins, 12 are protein complexes, and the rest are aqueous proteins important for the biology we will learn from their structures. The associated disease was the last thing we considered, as we were looking at the bigger picture of the biology. That being said, for the upcoming proteins flying you can almost name a disease: cystic fibrosis, diabetes; several types of cancer, including colon and prostate; many antibacterial proteins; antifungals; etc. There are even some involved with understanding how cells produce energy, which I suspect could lead to a better understanding of molecular energy.

Not long ago a Nobel Prize was awarded for the mapping of the ribosomes complex protein structure. This key cellular structure will also fly for study aboard the space station, because the resolution was not all that great using the ground-grown crystals. We now have the chance to learn more about how the ribosomes actually makes proteins and clarify the whole process. This is just one of the exciting projects flying in relation to protein crystal growth.

Crystallized structure of a nucleosome core particle that was grown aboard the Mir space station. (NASA)

This space station experimentation is a double blind study. This means that all the experiment chambers are bar coded for anonymity. We also will have exact controls done with the exact same batch of proteins prepared at the same time. The crystals will grow for the same length of time, as they are activated simultaneously in space and on the ground. When the samples come down, we will perform the entire analysis not knowing which are samples grown in space versus Earth. Only one engineer will have the key to the bar codes. When we’re completely done with the analysis, then he will let us know which were from space or ground. This will allow our study to provide definitive data on the value of space crystallization.

We also wanted to ensure that our analysis looked at a sufficient number of samples, statistically speaking, to provide conclusive data. How many data sets we collect per crystal sample will depend on the quality of that crystal. Statistically the study will be relevant in terms of how many proteins we fly, as well as how many crystals we evaluate from space and ground to make the comparison.

Astronaut Nicole Stott works with the high-density protein crystal growth (HDPCG) apparatus aboard the International Space Station. (NASA)

The microgravity environment is so beneficial because it allows the crystals to grow freely. Without the gravitational force obscuring the crystal molecules, as seen on Earth, the crystals can reveal their full form. We are giving all of these protein crystals the chance to grow to their full size in a quiescent environment. This is a very important investigation, not only because of the high number of proteins we are flying, but the statistical way we will evaluate them. Based on the results of the study, we will know if PCG in space is worth continuing.

Once the crystals come back to Earth, it will take at least one year to complete the full analysis. However, we will likely know that we’ve got some exciting results within the first three months. To publish something, it will be at least a year to complete the analysis, as we will have about 1,400 data sets to analyze. These results will determine the future of microgravity protein crystallization.

Larry DeLucas, O.D., Ph.D. (University of Alabama at Birmingham)

Larry DeLucas, O.D., Ph.D. is Director for the Center of Structural Biology and a professor at the University of Alabama at Birmingham. Dr. DeLucas flew as a payload specialist on the United States Microgravity Laboratory-1 flight, Mission STS-50, in June1992. His work is currently funded through NASA and the National Institutes of Health.

Space Station 15 Year Milestone — Measure and a Motivation

In today’s A Lab Aloft, International Space Station Chief Scientist Julie Robinson, Ph.D. speaks with NASA experts in microgravity research disciplines. Together they take the opportunity of the 15 year anniversary of the station to reflect on accomplishments and discuss what’s next aboard the orbiting laboratory.

It’s hard to believe that the International Space Station has already celebrated 15 years in orbit with the anniversary of the first module, Zarya. That decade and a half included nail-biting spacewalks, and an assembly of parts designed and built around the world that was a miraculous engineering and international achievement. Our research ramped up after assembly was completed in 2011, and we are nowhere near done. In fact, with NASA Administrator Charlie Bolden’s recent announcement that the space station will continue operations till 2024, this is a time of opportunity. With full utilization already at hand, an ever-growing research community is enthusiastic about what’s next in discoveries and benefits for humanity.

A look at the International Space Station in its early days shows the Zarya module (left) connected to the second element, the US Unity module (right). (NASA)

I want to share with you the thoughts from some of my colleagues who have worked to enable these key achievements leading up to this milestone year for the various space station disciplines. I also asked them to share what they look forward to as we continue. With space station planned for the next decade and likely beyond, this is no time to rest, but to ramp up and make full use of this amazing laboratory.

The most important development on the space station is the emergence of a public-private partnership enabled by congress in designating the station as a National Laboratory. Managed by the Center for the Advancement of Science in Space (CASIS), this National Laboratory provides funding avenues for universal access for users, in addition to NASA-funded research. “Through the creation of CASIS, our organization is able to leverage partnerships with commercial companies, other government agencies and academic institutions to generate a variety of research capable of benefitting life on Earth,” said Gregory H. Johnson, President and Chief Executive Officer of CASIS. “The foundation of NASA-funded research discoveries on the space station helps us work with new users interested in applied research. Each year this user base is expanding due to the past success and the future promise of life sciences, materials science and Earth remote sensing.”

From a technology perspective, the design and assembly of the space station is a major international collaborative achievement in and of itself. Beyond this, the station is a unique technology test bed for everything from remote Earth sensing instruments to life support for distant destinations, such as an asteroid or Mars. As NASA’s International Space Station Technology Demonstration Manager George Nelson noted, “In these first 15 years of the space station we have managed to launch, activate, and use the state-of-the-art spaceflight systems that enable long-duration human missions. We continue to evaluate their performance and, using what we learn, we are taking steps to mature those systems in ways that better allow us to explore our solar system.”

The completed International Space Station took 115 assembly flights to complete and researchers conducted more than 1,500 investigations in the first 15 years of assembly and operations. (NASA)

When it comes to remote Earth sensing, the space station is not only a test bed, but an orbital platform capable of providing a constant watch on our planet, as well as our universe. William Stefanov, Ph.D., senior remote sensing specialist with NASA’s International Space Station Program Science Office, provides an overview of the station’s orbital perspective on our planet.

“During the past 15 years, the space station has become recognized as a valid and useful platform for Earth remote sensing,” said Stefanov. “Handheld camera imagery collected by astronauts from the earliest days of the station have demonstrated its usefulness as both a compliment to more traditional free-flyer sensor systems and as a vantage point in its own right, providing unique opportunities to collect both day and night imagery of the Earth system due to its inclined equatorial orbit.”

Major new instruments will be arriving during the coming years, including ISS RapidSCAT and the Cloud-Aerosol Transport System (CATS) in 2014. Looking to the future, Stefanov touched on anticipated benefits, such as those already realized by the use of the Hyperspectral Imager for the Coastal Oceans (HICO) instrument. Data from HICO is accessible to the public through the OceanColor website maintained at Goddard Space Flight Center. HICO also is now available for new data collection requests through a proposal submission process.

“The space station is now viewed by NASA and its international partners as an attractive platform to test and deploy advanced multispectral and hyperspectral passive sensor systems for land, oceanic/coastal, and atmospheric remote sensing,” said Stefanov. “We also can support humanitarian efforts related to disaster response through collection of remotely sensed information for disaster-stricken areas. The capacity to host active sensor systems, such as lidar, is also being explored. The space station is well on its way to expand its role as a test bed and become an integral part of the NASA fleet of Earth remote sensing satellites.”

Hurricane Raymond as photographed by astronaut Karen Nyberg from the vantage point of the International Space Station on October 22, 2013. (NASA)

While the various sensors aboard station take quite a bit of physics into account, it’s important to note that there’s plenty of physics going on inside, too. The space station also is a laboratory for fundamental physics microgravity research. I spoke with International Space Station Fundamental Physics Senior Program Executive Mark Lee, Ph.D., about station contributions in this discipline.

“In the past 15 years I think we have done a couple of really important investigations on the space shuttle before the space station came into use,” said Lee. “Specifically the Lambda Point Experiment (LPE) and the Confined Helium Experiment (CHEX) investigations. These two look at the quantum effect in a very low temperature also coupled with the dimensionality in a bulk three dimension, versus a confined limit to a two dimensional space, to see how the quantum physics behaved. These studies were provided by Mother Nature of which we cannot change, but from now on we can design our own quantum systems.”

According to Lee, quantum physics is mysterious and still barley understood, making future investigations fertile grounds for progress. “Though humanity has known of quantum physics for just a about 100 years, before the 1990s, however, we had to rely on nature to provide us with a quantum system. For instance, superconductivity, superfluid in liquid helium, even a neutron star and a black hole are gigantic star quantum systems. In the next decade on the space station we are developing the Cold Atom Laboratory (CAL) as a ‘designer’s quantum system’ apparatus.”

A multi-user facility, CAL’s design will enable the study of ultra-cold quantum gases in microgravity from aboard the space station. The primary goal is to explore extremely low temperatures, previously inaccessible, for quantum phenomena.

Artist’s concept of an atom chip for use by NASA’s Cold Atom Laboratory (CAL) aboard the International Space Station. CAL will use lasers to cool atoms to ultracold temperatures. (NASA)

Lee continued, “The ability to study Bose Einstein condensates (BEC) and extremely cold atoms in space is a totally new dimension. With the kind of manipulation we will have in CAL, we can create different atom interactions and novel quantum configurations in such a way by manipulating individual atoms to look deeply into the quantum effect. Even Einstein’s Equivalence Principle (EEP) can be tested in space for the first time using this quantum system vs. that of previous classical ones. This is a very exciting area. This excitement, of course, is reflected in the Nobel Prize awards for related areas of study in 1997, 2001 and 2005. I can’t wait to see what happens when researchers can superbly cool and control a quantum system on the space station.”

Another exciting area of study in microgravity is that of physical science. Natural elements such as fluids and fire react quite differently and are some particularly interesting and useful areas of study in this environment. Program Executive for Physical Sciences, International Space Station Research Project Fran Chiaramonte, Ph.D., also weighed in on where we’ve been and where we are going.

When asked about the discipline of physical science in microgravity thus far, Chiaramonte responded, “I think the top achievement was the cool flames discovery. This was made when flames were detected at a temperature significantly below the known ignition temperature for the liquid droplet fuels we were studying in space. This came out of what we call the Flame Extinguishment Experiment (FLEX) where we were looking at droplet combustion in the Combustion Integrated Rack (CIR). The finding was unexpected from that research. Follow-on investigations will continue the quest to understand these flames and better define their characteristics. This has applications in the automotive industry—the findings would hand off via research publications and would be of value to them.”

Flames, like the one pictured here from the Flame Extinguishing Experiment (FLEX), burn more perfectly in microgravity, helping researchers get a better understanding of the nature of combustion in space and on Earth. (NASA)

Chiaramonte cited that in looking to the future, it is the early space station investigations that provide the basis for what’s next. Especially when talking about fluid physics. “In complex fluids, it started with a series of very simple experiments on phase separation between a host liquid and polymer particles. In a weightless environment, these particles will remain suspended in the solution almost indefinitely. On Earth they would settle to the bottom of the container and the experiment would be over before any meaningful science could be done. Over time the particles clumped together and separated out of the solution.”

“These precursor experiments led up to the next series of tests, called the Advanced Colloids Experiment (ACE) series,” continued Chiaramonte. “Now scientists study similar types of solutions under a microscope with a range of magnification and we are looking for a more strategic outcome. For instance, Paul Chaikin, Ph.D., is studying the self-assembly of particles, which has been a plaguing challenge for the future of advanced optical materials. In that work, they have successfully arranged one-dimensional line of particles, and have now successfully arranged a two-dimensional line of particles. This has important industrial applications.”

The gel structure, like that under investigation in the Advanced Colloids Experiment (ACE), is often dominated by fragile strands composed of many particles in a cross-section. (NASA)

“It will take many researchers beyond Chaikin’s work,” said Chiaramonte, “but by using the space station for that kind of study, we can anticipate a major contribution in this area of three-dimensional ordering of particles and optical computing.”

From questions looking at the microscopic scale of physical phenomena, we now move on to the important minutia within our own bodies with the study of life sciences in microgravity. In speaking with Space Biosciences Division Chief Sid Sun, the research that stands out to him from the space station’s tenure involves the importance of where we’re heading next.

“In life sciences what we’ve been able to do over the last 15 years is answer at a first level the various questions that are associated with life in space,” said Sun. “Essentially how the unique environment of space, such as the microgravity and different radiation levels affect living organisms. As is typical with science, every time you answer one question, a whole other set of questions pop up, so that’s where the future of the research will take us. In particular, we’ll be studying more of the changes in the genomics of living systems.”

Astronaut Sunita Williams, Expedition 14 flight engineer, prepares a laptop for data entry during a blood draw as part of the Nutritional Status Assessment (Nutrition) study in the Destiny laboratory module of the International Space Station. (NASA)

“Something that the advances in biotechnology are allowing us to do now is better understand what is happening in the basic genetic code within organisms and how that code is being expressed or not expressed in space compared to Earth,” Sun continued. “The space station allows studies of record length for a wide variety of organisms. On the space shuttle scientists were limited to from 10 to 14 days every five years. Now with the continued orbit of the space station we are able to do experiments in microgravity for months, maybe heading into half a year to a year in length, and we continuously have scientists study a wide variety of organisms. That is going to be especially critical as we look to study humans in space for multiyear missions.”

These findings flow to future areas of study, where model animals will play an important role. “Being able to study other organisms, especially rodents, will shed a lot of insights into how spaceflight will be affecting people for long periods of time. In particular, during space station assembly, pharma demonstrated that space biomedical research could enable both drug discovery on Earth and biomedical research important for astronauts. With the new Rodent Research Facility we’re developing for the space station we’re going to take that research to the next level, again taking that research into longer experiments and having more animals up there. It will be high speed compared to the experiments of the past.”

An engineering drawing of NASA’s Rodent Research Facility that will operate aboard the International Space Station. (Lockheed Martin)

While model animal studies are key to human health developments, our crew also serves as test subjects for a variety of important investigations. From the beginning, our astronauts collected samples, kept journals and participated in experiments to help increase the understanding of what life in space meant for the human body.

“The first 15 years of the space station provided us with a much deeper understanding of how humans respond to six months of space flight and how to deal with those changes,” said Craig Kundrot, Deputy Chief Scientist, Human Research Program. “We have learned how to prevent or limit problems like bone loss, muscle loss, or aerobic fitness. We have discovered new changes that were not as clear in the one to two week long shuttle missions: changes in the immune system and visual impairment, for example. We have pushed technology to new limits, like the use of ultrasound for the detection of bone fractures and kidney stones.”

“In the ensuing years, we seek to overcome the remaining challenges like visual impairment,” Kundrot continued. “We also plan to progress from overcoming the challenges one at a time to overcoming the challenges with an integrated suite of countermeasures and technologies that keep the astronauts healthy and productive in future exploration missions.” These findings and the development of countermeasures and treatments are not limited to space explores, but have real world applications. From strengthening bones for those suffering from osteoporosis to boosting the immune systems of the elderly and immunosuppressed, there is much to gain from human research in microgravity.

With so much to be proud of in our 15 years of assembly and operations, it’s not surprising we have plenty to look forward to. From my perspective, I am particularly excited to see what space station researchers will discover next. Now is the time for microgravity studies to come into their own. While these future endeavors are fascinating, I am especially touched by the ways such findings return for expanded use on the ground. Whether addressing health concerns, advancing engineering designs, or inspiring the next generation, the space station may have already secured its place in history, but we are far from mission end. If anything, we have only just begun!

Julie A. Robinson, Ph.D.
International Space Station Chief Scientist

The Sense in Earth Remote Sensing from the International Space Station

In today’s A Lab Aloft blog entry International Space Station Chief Scientist Julie Robinson, Ph.D., shares the benefit to using the space station as a platform for Earth remote sensing instruments.

One of the amazing things that you’re going to see on the International Space Station in the coming years is its emergence as a serious remote sensing platform. Looking at the Earth from space gives researchers a powerful vantage point to study our planet’s water, air, vegetation, and more.

People in remote sensing are used to having their own satellites and putting those instruments at the perfect orbit so that they go over the ground at the perfect time. Fortunately, when the space station was designed, planners recognized that having a platform in low Earth orbit (LEO), which is about half the altitude of most Earth remote sensing satellites, provided researchers the opportunity to do something unique. Designers put locations on the station exterior that provide data, thermal and power support. Basically the space station is a giant, well-equipped satellite that can host a wide variety of remote sensing instruments—dozens of them.

A detailed view of the location for Stratospheric Aerosol and Gas Experiment III (SAGE-III) instrument, once it is externally mounted to the International Space Station. You can see the numerous other mounting locations available for other remote sensing investigations. (NASA) — A detailed view of the location for the Stratospheric Aerosol and Gas Experiment III (SAGE-III) instrument, once it is externally mounted to the International Space Station. You can see the numerous other mounting locations available for other remote sensing investigations. (NASA)

Now that the space station is complete, we are starting to see scientists take advantage of this platform as their sensors get launched and mounted. I want to talk a little bit about why these instruments are finding a valuable home on the space station. I also want to mention that there are openings through the Earth venture instrument opportunity and other calls via NASA’s Mission Directorate for both small, lower cost instruments and venture-class instruments. It’s wonderful to see the entire Earth science community looking at how the space station can help them achieve their research goals.

One huge advantage to using the space station is the frequent transportation to orbit. The abundant power and data capabilities are also tremendous benefits. Something else to consider is that station is a bit more jittery compared to other Earth remote sensing satellites, but engineers can adapt designs to work around this, as well as to manage contamination concerns for such a complex vehicle.

When I look at the instruments coming to the space station, one thing that is singular is the 51.6 degree inclination of our platform. That means that instead of passing over at the same time every day, which is typical of an Earth remote sensing satellite, the space station actually has a precessing orbit and does not go over the poles. In other words, the ground track moves westward along each of 16 daily tracks as it travels, with ground track repeats every three days, and a 63-daylight cycle. That gives you some unique opportunities. While at first it may not appear ideal for certain kinds of Earth remote sensing, researchers are working with that difference to turn it from a challenge into an asset.

The precessing orbit of the space station laid out over a map of the Earth. (NASA)

What I’m seeing in the instruments coming forward are some trends in how they are using the space station to their advantage. One area is in the capability to fill data gaps using station-mounted sensors, specifically where other satellites have failed or not yet made it to orbit. Station provides a rapid turnaround opportunity to fill those data gaps, providing a fuller insight into each area of research.

A second trend I’ve noticed has to do with areas where there is a new airborne technology. People would like to have those get on global satellites, but first the instruments need to be tested and the technology refined. The space station is a great place to do that kind of advancement, so that in the future the more expensive satellite mission can be successful.

Another group of instruments are taking advantage of the diurnal—daytime and daily activity—variability of the station. For instance, if you have a sensor on a satellite in sun-synchronous orbit, it goes over the ground at the same time every day. When you add a second, parallel instrument you can take advantage of observing things at different times. Think of MODIS, which is going over the tropics daily at the same time. That area may be cloudy most of the time, because of the specific schedule. With the space station, however, you could now and then get that same data early in the morning before the clouds have built up.

The Earth's atmosphere seen in the thin blue line fading into the darkness of space, as photographed by a crew member aboard the International Space Station. (NASA) — The Earth’s atmosphere seen in the thin blue line fading into the darkness of space, as photographed by a crew member aboard the International Space Station. (NASA)

Another pattern we are seeing is the opportunity for cross-calibration, where researchers compare data sets from both the station- and satellite-related sensors. It can be really valuable to have a second instrument aboard station for this cross-validation of data. There are several instruments in orbit now, and the station will eventually pass under each of those sensors and simultaneously collect data. That allows for the cross-calibration of instruments that would otherwise be impossible.

With that as a background, here are a few highlights of instruments coming up for use aboard the space station for remote Earth sensing.

The Stratospheric Aerosol and Gas Experiment III (SAGE-III) is a spectrometer that uses occultation. This basically means that it looks at the light transmitted from the sun or the moon filtered through the atmosphere and measures the aerosols that are found there. SAGE-III is scheduled to launch to the space station in 2015. This latest spectrometer has a heritage of previous SAGE instruments that discovered the ozone hole, which we all know about now and that led to the 1987 Montreal Protocol.

The updated SAGE-III will help us understand atmospheric composition and long-term variability. The space station’s orbit is actually ideal for these types of occultation measurements. Having the opportunity to mount this major instrument to our platform is thrilling.

The Stratospheric Aerosol and Gas Experiment III (SAGE-III) instrument, seen in this artistic rendering, is scheduled to launch to the International Space Station in 2015. It will capture remote Earth sensing data of the aerosols in the atmosphere. (NASA)

Another instrument that is going up to station very soon on SpaceX-5, scheduled for 2014, is a LIDAR instrument looking at clouds. Called the Cloud Aerosol Transport System (CATS), this sensor will mount to the JEM exposed facility. This is a case of testing an instrument that was developed for airborne use, but has not flown on a satellite yet.

What CATS does is it emits a laser light signal at three different wavelengths. It then looks at the signal that comes back to measure the layer height of the clouds, the layer thickness, the backscatter (the reflected light back), the optical depth and the depolarization. In so doing, CATS helps us understand the structure of those clouds. This is hugely important for global climate modeling, because clouds can function as insulators. They can prevent sun from getting to the ground, and they also can prevent heat from getting out of the Earth.

Sample LIDAR data from the airborne Cloud Physics LIDAR, predecessor to the Cloud Aerosol Transport System (CATS), showing cloud heights and aerosol layers. (NASA)

The ISS-RapidScat also is planned for launch to space station in the not too distant future. This is a radar scatterometer measuring ocean wind speeds. The instrument is a refurbished engineering model of the sea wind scatterometer that was on QuickScat, which had some failures. This updated version is a data gap filler and the information is used by the National Oceanic and Atmospheric Administration (NOAA) and other agencies in predicting hurricane intensification and understanding these major storms. The next satellite scatterometers that will go up are going to have intersections with ISS-RapidScat. It’s inspiring to see the cross-calibration capabilities that come with this series of instruments.

An artist rendering of the ISS-RapidScat aboard the International Space Station. This instrument will measure wind speeds to provide hurricane prediction data to researchers. (NASA)

The space station provides this extraordinary emerging opportunity with rapid implementation of airborne and space-borne instruments to fill data gaps. This includes the ability to test an airborne technology globally before launching a premier satellite-based instrument, as well as the ability to take advantage of the somewhat unusual space station orbit tracks. We can capture diurnal opportunities that other instruments miss and even use the data to cross-calibrate across a constellation of sensors to really improve the quality of the overall global data sets.

We are going to have our first dedicated session for space station remote Earth sensing at this year’s American Geophysical Union meeting in San Francisco, from December 9-13, 2013. It is encouraging to have all of these newer science instruments coming to space station in the next year or two. I am thrilled to see the scientific community putting their creativity out there as they think about what instruments make sense for the space station and proposing those in solicitations.

Julie A. Robinson, Ph.D.
International Space Station Chief Scientist

Cool Flames on the International Space Station – An Anatomy of Discovery

In today’s A Lab Aloft, Mike Hicks, project scientist at NASA’s Glenn Research Center in Cleveland, blogs about discovering the “cool” world of combustion aboard the International Space Station.

In a recent posting on this blog one of our International Space Station combustion researchers, Sandra Olson, noted that when it comes to combustion experiments in microgravity one should expect surprises. This has certainly proven to be true with one of our liquid fuel combustion investigations currently operating aboard the space station.

The Flammability and Extinction (FLEX) study burns liquid fuels dispensed in the form of small, single droplets. The goal is to answer two key questions: the first is how difficult it is to keep a flame burning in microgravity? We call this flammability mapping. The second is how effective is gaseous carbon dioxide (CO₂) (or other diluents) in extinguishing spacecraft fires? Gaseous CO₂ is particularly important because this is the current fire suppressant used in the U.S. module of the space station.

To answer these and other “burning questions” the FLEX team of scientists studies small droplets of fuel. This approach allows a large number of tests to take place under a wide range of conditions. The flame that results from igniting these fuel droplets (ranging in size from 1.0 mm to 6.0 mm in diameter) achieves a shape that can only happen in a reduced gravity environment—that is, they become little glowing balls of fire.

Image of a burning droplet in microgravity during a Flammability and Extinction (FLEX) test aboard the International Space Station. (NASA)

Within fractions of a second following ignition, the reaction front—visualized as a flame—quickly wraps around the fuel droplet and assumes a spherical shape. This remains mostly motionless until the droplet of fuel is consumed or until the conditions are such that the flame can no longer exist. You can watch the Strange Flames on the International Space Station video to see these microgravity flames in action.

The overarching goal of FLEX is to better understand the complicated physical processes behind determining whether or not a flame can exist in a given environment for a given fuel type. The environment varies based on the amount of oxygen in the combustion chamber along with other gases that balance out the test atmosphere.

Since combustion processes are rich in physics and chemistry, there are many parameters that play a role in flame survival. The FLEX experiments allow scientists a way to study these competing physical processes—such as the rate of fuel consumption, fuel characteristics, the controlling energy and mass transfer processes, and the physical properties of the gases that make up the test environment. By understanding and modeling these processes, we hope to better predict fire behavior in space. This also leads to Earth technology advances, such as more fuel efficient engine designs.

FLEX recently led us to a “cool” discovery, igniting the imaginations of many combustion researchers. During one of their many late night test sessions, the FLEX operations team noticed a very peculiar orange afterglow about 20 seconds after the flame had extinguished. It was so intense that the team first thought something else other than the fuel droplet was burning.

A cloud of condensed fuel, like a fog, forms around the heptane fuel droplet following its dual-stage extinguishment in the FLEX investigation. (NASA)

After a few repeated tests, the team concluded that this bright afterglow resulted from tiny droplets of re-condensed fuel vapor. The idea was that these tiny droplets formed a fog, scattering the yellow-orange backlight that is used to project the droplet’s shadow onto one of the diagnostic cameras. The afterglow was initially dismissed as an artifact of the test configuration—or so we thought.

A few days later we recovered the data from the space station and processed the images for accurate measurements. As we looked closely at the droplet shadow images we realized this glow was actually a clue to something new.

Typically when a flame extinguishes, the evaporation of the fuel droplet will nearly stop, and the droplet stops shrinking, which makes entirely good sense—no flame, well then, no fuel consumption. We discovered with FLEX that under certain conditions when the flame disappeared, the droplet of fuel continued to evaporate at almost the same rate as when the flame was visible. In many cases this “apparent” fuel consumption without a flame lasted longer than with the flame.

Video screen shot of a FLEX ignition test for a ~2.5 mm methanol fuel droplet formed on tip of needle. (NASA)

Even more startling, we saw that when the pressure of the chamber was slightly increased, the flame momentarily reappeared in a brief flash before quickly going out again. In some cases this phenomena repeated until the fuel was consumed. This finding has a number of interesting ramifications, both from a purely scientific perspective as well as from a fire safety perspective. It provides the first direct observation of a long held concern—the possibility that microgravity conditions were conducive to re-ignition of flammable mixtures.

Ignition of 4.5 mm droplet on tethering fibers (crossed fibers shown as glowing lines) developing into a large weak flame which quickly extinguishes (t = 10.8 seconds), followed by period of low-temperature burning (~ 2 seconds) with no visible flame, a brief return to high-temperature burning (for ~ 1.5 seconds at t = 12.9 seconds). This cycle repeated once, until the fuel droplet was completely consumed. (NASA)

At first glance, it seemed irrational that the fuel droplet continued to evaporate with no visible flame. Some of the science team argued, myself included, that this could be explained by characteristics of the test chamber environment. It was suggested that once the visible flame extinguished, that there was still a sufficient amount of energy remaining in the surrounding gases to continue the rate of the droplet’s evaporation.

Since buoyant forces are absent in microgravity flames, the hot gases simply remain stationary around the droplet—so we theorized that as these gases cooled, heat transferred back into the droplet. We quickly realized, however, that this would have resulted in a gradual slowing of the droplet’s evaporation rate, which was not the case. During the “dark burning periods” when no flame was visible, the evaporation rates were essentially constant, similar to what is seen with a visible flame. Interestingly, these evaporation rates suddenly stopped when the afterglow of the scattered light began to appear.

In 65 years of previous droplet experiments, and employing a staggering breadth of microgravity test configurations—from converted mine shafts in Japan to experiments performed on the recently retired space shuttles—this phenomena had never been observed. The prior universal observation was that when the flame went out, the rapid evaporation of the droplet stopped. However, with these tests we now had a fuel droplet that continued to be consumed at a rapid rate without an apparent flame.

NASA astronaut Karen Nyberg, Expedition 36 flight engineer, services the Combustion Integrated Rack (CIR) Multi-user Droplet Combustion Apparatus (MDCA) in the International Space Station's Destiny laboratory. This is the facility in which the FLEX investigation tests take place in orbit. (NASA) — NASA astronaut Karen Nyberg, Expedition 36 flight engineer, services the Combustion Integrated Rack (CIR) Multi-user Droplet Combustion Apparatus (MDCA) in the International Space Station’s Destiny laboratory. This is the facility in which the FLEX investigation tests take place in orbit. (NASA)

After a great deal of deliberation, the collective wisdom of the FLEX team came up with a theoretical explanation: “cool flames!” The technical explanation for this phenomena first appeared in Combustion and Flame in an article entitled “Can Cool Flames Support Quasi-Steady Alkane Droplet Burning?”

So what exactly is a cool flame and why is it important? The discovery of cool flames is often attributed to Sir Humphry Davy in 1812. While investigating flames for the purpose of designing safety lamps for coal miners, Davy observed that he could generate flames in the lab that were so weak that they could would not even ignite a match. This finding was followed by W.H. Perkins, who published in 1882 the first investigation of cool flames. Perkins observed that vapors of organic fuels produced what he characterized as “blue lambent flames.” Generally speaking, cool flames are the visible light of oxidation reactions occurring at low temperatures, sometimes nearly 10 times less than normal flame temperatures.

This side-by-side image shows a comparison of a flame burning on Earth (left) and a flame in microgravity (right). (NASA)

Cool flame temperatures depend on fuel type and atmosphere. For n-heptane—the alkane fuel used in the FLEX experiments—cool flames appear at temperatures just above 600 degrees Fahrenheit. This is about 176 degrees Fahrenheit warmer than the temperature for baking bread and considerably less, by about 1,300 degrees Fahrenheit, than the flame one might roast a marshmallow over. Hence the name “cool flame.”

Despite the name, these flames’ temperatures are still sufficiently high to sustain chemical reactions. Understanding exactly what kind of chemical reactions are taking place, as well as the conditions necessary to propel the chemistry into the high temperature realm of hot flames, are key research areas in the study of cool flames.

Prior to the FLEX discovery, it was thought cool flames were primarily pre-ignition phenomena generally limited to pre-mixed gases. If you’ve ever taken your car in for engine knocking, you’ve experienced an example of this. Pockets of gas in the cylinder undergo low temperature reactions (i.e., cool flames) that result in poorly timed pressure peaks. These deviations from the optimal peak pressure timing that should occur shortly after spark ignition result in the noise often associated with engine knock.

The FLEX study, however, showed a post-ignition cool flame. This occurred in a controlled system where reactants are initially separated, requiring time to travel to the reaction zone, which we see as the flame. This appears as a relatively steady phenomenon, suggesting a delicate balance between heat generated by the reaction and heat losses to the surrounding—to date, only achievable in space.

The microgravity cool flame discovery is significant for a number of reasons. Low temperature combustion in internal combustion engines, for instance, offers a number of advantages: reduced emissions, less wear on engine parts and increased fuel efficiencies. A better understanding of these low temperature burning regimes may help address challenges facing new internal combustion technologies, such as the Homogenous Charge Compression Ignition (HCCI) and Reactivity Charge Compression Ignition (RCCI) engines. Since these technologies lack a spark for localized ignition, knowledge of cool flames may help with precise timing of the combustion event—based, in this case, on a reactant mixture that may only be partially pre-mixed.

Microgravity cool flames are exciting in their own right, because of the potential for refining our understanding of a very complicated combustion phenomena. This is true of all serendipitous discoveries, giving one more example of how the space station provides an opportunity for discoveries that would otherwise never get made.

Mike Hicks is pictured with his granddaughter, Emma, while roasting marshmallows over “cool” flames of another kind. (Image Courtesy of Mike Hicks)

Mike Hicks, project scientist at NASA’s Glenn Research Center in Cleveland, has been with NASA for 22 years and is currently probing the mysteries of droplet combustion as a co-investigator on the Flammability and Extinction (FLEX) study. He is also the principal investigator on the Supercritical Water Mixture (SCWM) International Space Station flight investigation, which is designed to study precipitation phenomena in near-critical water. Hicks spends much of his free time as a doctoral candidate at Case Western Reserve University putting the finishing touches on a dissertation he plans to complete in the fall of 2013.

From Fluids to Flames: The Research Range of Space Station Physical Science

In today’s A Lab Aloft, guest blogger Fred Kohl, Ph.D., International Space Station Physical Sciences Research project manager at NASA’s Glenn Research Center in Cleveland, talks about some of the physical science investigations that take place in microgravity aboard the space station.

Extremes are part of exploration, whether you’re talking about space travel or probing new areas of discovery to expand knowledge in a given science. So it is appropriate that the extreme environment of the International Space Station provides an ideal location to study physical sciences, from flames to fluids.

Removing gravity from the equation aboard this Earth-orbiting laboratory reveals the fundamental aspects of physics hidden by force-dependent phenomena where a fluid phase (i.e., a liquid or gas) is present. Such experiments, which investigate the disciplines of fluid physics, complex fluids, materials science, combustion science, biophysics and fundamental physics, use the station’s specialized experiment hardware to conduct studies that could not be performed on the ground.

The main feature differentiating the space station laboratory from those on Earth is the microgravity acceleration environment that is stable for long periods of time. Conducted in the nearly weightless environment, experiments in these disciplines reveal how physical systems respond to the near absence of buoyancy-driven convection, sedimentation, or sagging. They also reveal how other forces, which are small compared to gravity, can dominate the system behavior in space. For example, capillary forces can enable the flow of fluids in relatively wide channels without the use of a pump.

Other examples of observations in space include boiling in which bubbles do not rise, colloidal systems containing crystalline structures unlike any seen on Earth, and spherical flames burning around fuel droplets. Also observed was a uniform dispersion of tin particles in a liquid lead melt, instead of rising to the top as would happen in Earth’s gravity.

These findings may improve the understanding of material properties, potentially revolutionizing development of new and improved products for use in everything from automotives to airplanes to spacecraft. With so much to learn in the area of physical science and so many investigations, I would like to highlight several studies ongoing, upcoming or recently looked at aboard the space station.

Constrained Vapor Bubble-2 (CVB-2)

Studying mixed fluids in microgravity for CVB-2 provides data to further optimize the performance of wickless heat pipes. These pipes weigh less and have reduced complexity as compared to the more common construction with a wick. The CVB-2 study examines the overall stability, fluid flow characteristics, average heat transfer coefficient in the evaporator, and heat conductance of a constrained vapor bubble under microgravity conditions as a function of vapor volume and heat flow rate.

Findings from this research may lead to more efficient ways to cool electronics and equipment in space, while also applying to advances in Earth technologies such as air conditioning and refrigeration systems. Laptop computers also use this type of heat pipe technology to cool their electronics in order to prevent overheating.

Expedition 23 Flight Engineer T.J. Creamer works to setup Light Microscopy Module (LMM) and Constrained Vapor Bubble (CVB) hardware in the Fluids Integrated Rack (FIR) in the Destiny U.S. Laboratory. (NASA)

Advanced Colloids Experiment (ACE)

ACE studies colloidal particles in space for use in modeling atomic systems and engineering new systems. These particles are big enough—in comparison to atoms—to be seen and recorded with a camera for evaluation. Conducting this study aboard the space station removes gravitational jamming and sedimentation so that it is possible to observe how order rises out of disorder, allowing researchers to learn to control this process. This could lead to greater stability and longer shelf life for products on Earth, such as paints, pharmaceuticals and other products based on colloids. Recently we launched additional hardware, consisting of a magnetic mixer and a drill kit, to use in mixing the samples for future ACE experiments.

The magnetic mixer and drill kit (pictured here before launch) will assist with mixing samples for Advanced Colloidal Experiments (ACE) aboard the International Space Station. (NASA)

Capillary Flow Experiment-2 (CFE-2)

The CFE investigation is a suite of fluid physics flight experiments designed to study large-length scale capillary flows and phenomena in low gravity. Testing will probe dynamic effects associated with a moving contact boundary condition, capillary-driven flows in interior corner networks, and critical wetting phenomena in complex geometries. The sample fluids flow in specific directions influenced by the shape of unique cylindrical containers called Interior Corner Flow (ICF) vessels.

For CFE-2 there are 11 units of fluids for astronauts to test. This research and the resulting math models based on the data findings helps with the design of more efficient fuel systems for spacecraft. This is because the engineers will be able to design the shape of the tank to take advantage of the way fluids move in microgravity. On Earth these findings may contribute to models to predict fluid flow for things like ground water transport, as well as the afore mentioned cooling technology advances for electronics.

Expedition 36 Flight Engineer Karen Nyberg conducts a session with a Capillary Flow Experiment (CFE) Interior Corner Flow vessel in the Harmony node of the International Space Station. CFE observes the flow of fluid, in particular capillary phenomena, in microgravity. (NASA)

Flame Extinguishment Experiment – Italian Combustion Experiment for Green Air (FLEX-ICE-GA)

The objective of this investigation is to observe and characterize evaporation and burning of renewable-type fuel droplets in high-pressure conditions. Test runs for this study recently took place in the Combustion Integrated Rack (CIR) aboard station. Research conducted in the CIR facility includes the study of combustion of liquid, gaseous and solid fuels. The CIR is made up of an optics bench, combustion chamber, fuel and oxidizer control, and five different cameras for performing combustion experiments in microgravity.

Researchers can use the results of these experiments to develop and validate thermo-chemical and chemical kinetics computer models of renewable liquid fuels for combustion simulation in engines. This helps with the design of the next generation of fuels and advanced engines. The computer models may reduce costs to industries and benefit the general public by accelerating the adoption of renewable fuels that are environmentally friendly.

NASA astronaut Tom Marshburn servicing the Combustion Integrated Rack (CIR) aboard the Destiny module of the International Space Station. (NASA)

Supercritical Water Mixture (SCWM)

The SCWM investigation will help researchers look at phase change, solute precipitation, and precipitate transport at near-critical and supercritical conditions of a dilute salt/water mixture. When water is taken into its supercritical phase—a temperature higher than 705 degrees Fahrenheit and a pressure higher than 3,200 psia—it becomes highly compressible and begins to behave much like a dense gas. In its supercritical phase water will experience some rather dramatic changes in its physical properties, such as the sudden precipitation of inorganic salts that are normally highly soluble in water at ambient conditions.

The primary science objectives of the SCWM investigation are to determine the shift in critical point of the liquid-gas phase transition in the presence of the salt, determine the onset and degree of salt precipitation in the supercritical phase as a function of temperature, and to identify the predominant transport processes of the precipitate in the presence of temperature and/or salinity gradients.

On Earth water reclamation from high-salinity aquifers, waste handling for cities and farms, power plants, and numerous commercial processes may benefit from the SCWM findings. A good understanding about the behavior of salt in near-critical and supercritical conditions also would assist designers of the next generation of reactors. With the knowledge gleaned from SCWM, they could possibly design systems that would operate without incurring large maintenance problems.

Sample cell filled with a dilute aqueous solution of sodium sulfate for the Supercritical Water Mixture (SCWM) investigation. (NASA)

With the still relatively new frontier of microgravity research, there are many questions to pose and angles to consider. The scientists that pursue the answers using the laboratory we have available 200 miles above us are embarking on a journey of discovery that I dare say will yield some amazing findings. As Albert Einstein said, “To raise new questions, new possibilities, to regard old problems from a new angle, requires creative imagination and marks real advance in science.”

Fred Kohl is the International Space Station Physical Sciences Research project manager at Glenn. Since the mid-1980s, he’s been involved in the advocacy, definition, development and conduct of more than 250 experiments in ground-based facilities and aboard the space shuttles, Mir space station and the International Space Station in the disciplines of fluid physics, complex fluids, combustion science, fundamental physics, materials science and acceleration environment characterization. Before joining the microgravity program, he conducted research in high-temperature materials chemistry and high-temperature materials corrosion related to aircraft engine applications. He holds a B.S. in chemistry from Case Institute of Technology and a Ph.D. in chemistry from Case Western Reserve University.