Otto Hasekamp is a senior scientist at the Netherlands Institute for Space Research (SRON) and is the science lead for the SPEXOne polarimeter that will be on PACE.
What is your favorite atmospheric or oceanic related book or movie?
It’s not a book, but my favorite bit of writing about the atmosphere is actually a review article from 1974 – the year I was born! – on light scattering by atmospheric particles. It’s something that I’ve come back to through my whole career. It was written by Jim Hansen and Larry Travis from NASA’s Goddard Institute for Space Studies in New York, and is sort of the cornerstone for polarimetry.
What are you most looking forward to during launch?
I’m really excited to see the satellite go up and then get the notification that everything has gone right with the satellite. It will really be a relief, and I’m looking forward to that green light.
What are you most looking forward to post-launch?
The commissioning phase where we check all the measurements and the instrument will be an exciting and intense period. I’m really looking forward to the first measurements of SPEXOne. On the somewhat longer term I look forward for our team to first real science results, that improve our understanding of aerosols and clouds.
What is your favorite color and why?
My favorite color is blue. Why? Well, of course when the sky is really clear it shows up very blue and I think that’s a great thing to look at.
Otto Hasekamp at the Berger Kogel, Austria, September 2023. Courtesy of Otto Hasekamp
Do you have a favorite type of cloud or atmospheric phenomenon?
The very, very thick clouds when there’s a thunderstorm coming that are sort of scary to see. It gives a special atmosphere.
What’s a fun fact about yourself, something that people might not know about you?
I like hiking in the mountains. Every year, for 25 years, I go hiking in the mountains with friends of mine and we hope to continue to do that for a long time. I’ve also crossed the Arctic Circle.
What advice would you give to aspiring scientists who are looking to get to where you are today?
Persist. Accept that things go slowly but persist and you will get where you want to be. I think that is maybe the most important one. Keep in mind the impacts of what you do, that’s another important one.
What is one catch-all statement describing the importance of SPEXOne?
It will help the understanding of the cooling effect that fine particulate matter has on the climate.
Header image caption: Otto Hasekamp presenting SPEXone at the International Astronautical Congress (IAC) conference, Washington, D.C., October 2019. Courtesy of Otto Hasekamp
By Erica McNamee, Science Writer at NASA’s Goddard Space Flight Center
Gary Davis is the mission systems engineer for PACE at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
What is your favorite ocean or atmospheric related book or movie?
I don’t know if it’s classified as a book, but I do like the Edgar Allan Poe story “A Descent Into the Maelstrom.” My favorite ocean movie? I really liked the movie “Master and Commander.” It’s not really an ocean movie, but a lot of it takes place on sailing ships, and they do have a naturalist in that movie who researches plants, insects, and other creatures.
What is your background?
I went to engineering school at the University of Virginia, got a bachelor’s degree in aerospace there, and then went to Princeton and got a master’s in mechanical and aerospace engineering. Essentially right out of school, I came to Goddard. I started off in the propulsion branch, and I worked on the TRMM mission – Tropical Rainfall Measuring Mission – and then the MAP mission – Microwave Anisotropy Probe. That’s a mouthful. Then I worked on the Solar Dynamics Observatory, I worked on the MMS mission – Magnetospheric Multiscale, another mouthful – and then OSIRIS-REx and now PACE.
Gary with PACE Observatory in SCA Cleanroom. Image Credit: Dennis Henry
What is your role in PACE?
For PACE, I’m the mission systems engineer, so I’m the chief engineer on the project. I have a great team working with me to hopefully make sure it all works.
What are you most looking forward to during launch?
I am most looking forward to the moment when we get the telemetry that the spacecraft is alive and is stable and pointing the solar arrays at the sun. That’s the most critical part for us, is to make sure that the spacecraft has survived the rigors of launch, and that it knows what to do and is pointed in the right direction. So that’s a huge first step for us.
And once that’s all clear, what are you most looking forward to post-launch?
I want to see that first picture. The instrument folks call it first light, and I’m just really excited to see what PACE’s instruments can do. We’ve been testing them on the ground for all these years, but they’re not looking at anything really, just the laser light that we shine in or the ceiling of the cleanroom. When the Ocean Color Instrument is able to see the ocean and the polarimeters see the aerosols in the atmosphere, it will be amazing to get that first image.
Since OCI will be looking at all these different colors of the ocean, what is your favorite color and why?
That’s an easy one. My favorite color is British Racing Green and the reason why is I’m a Formula One fan and my favorite team (though they don’t race anymore) is Lotus. Way back in the day, most of their cars were painted British Racing Green, so I’ve always loved that color. It’s a dark green, and it’s very fast.
Gary with U.S. Marine Band Trombone Section. Learn more here. Image Credit: U.S. Marine Band
What advice would you give to aspiring engineers who want to someday work on NASA satellites?
The obvious answer that a lot of people give is “study this science or study that math or take that engineering class” and I kind of go in the opposite direction. For folks who want to work on NASA projects in science or engineering, they’re probably already very strong in science and engineering, so they don’t need any more of that. My advice would be to study and be trained as much as possible in human skills, leadership, team-building, and how to work as part of a team. Especially in today’s world, with so many virtual ways to communicate, your team might not be co-located with you. The better communication skills you have and the better you can get an entire team to work efficiently with you, that means a lot. For any big project, you need multiple people, and even with great people, nobody can do it by themselves – you need a whole team.
What’s a fun fact about yourself, something that a lot of people might not know?
Gary with other double bell friends at Tubachristmas Kennedy Center. Image Credit: A nice Tuba Player
I’m a trombone player, amateur. I did buy a euphonium so I can play it once a year in Tubachristmas, which is super fun because we get to play the melody which you don’t usually get as a low brass player. So, for one night a year, I’m like a quasi-tuba player and it’s really fun.
What’s one catch-all statement describing the importance of PACE?
PACE is going to teach us answers about the ocean that we haven’t even been able to ask the questions for yet. It’s going to show us stuff that we don’t even know that we don’t know yet.
Header image caption: Gary with PACE Observatory during PACE Family Day. Image Credit: Dennis Henry
By Erica McNamee, Science Writer at NASA’s Goddard Space Flight Center
Kirk Knobelspiesse is an atmospheric scientist and the project science team polarimeter lead for PACE at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. He is also the polarimeter instrument scientist for the Atmosphere Observing System (AOS) constellation.
Kirk Knobelspiesse hiking sand dunes near Swakopmund, Namibia, during the ORACLEs field campaign. Image Credit: Michal Segal-Rozenhaimer
What is your favorite atmospheric or ocean related book or movie?
There was a series on Netflix called “Connected” that had an episode called “Dust.” The general idea is that everything in the world is connected, so it started with dust that was generated in the Sahara Desert, specifically the Bodélé Depression. And that dust – which is really from a dry lakebed – gets lofted into the atmosphere and goes out over the oceans, and in the process interacts with clouds and potentially fertilizes the ocean. That dust makes it all the way to the Amazon basin where it may also be an important source of nutrients.
What is your background?
I am a photographer who got really into imaging of all kinds, which led me to remote sensing. I ended up doing work on remote sensing of Earth from space and worked on SeaWiFs, which was an early ocean color mission. I decided I need to go back to grad school and get a more quantitative education, so I got an applied math degree at Columbia University.
What are you most looking forward to during launch?
Earlier in my career I worked on a satellite that had a launch failure (Glory in 2011). So, during launch, I am going to shut myself in a closet and not learn any news until somebody tells me it’s all over. Because it makes me so nervous. A lot of people want to go and see the launch and that kind of thing. Not me, I’m going to stay away. Somebody will tell me when it’s all over.
What are you most looking forward to post-launch?
Kirk Knobelspiesse in his office at NASA’s Goddard Space Flight Center in Greenbelt, Md. Image Credit: Kirk Knobelspiesse
I have a list of all the Science and Nature papers we’re hoping to write with PACE data. It’s ambitious, a little bit. But there are new types of observations that we will be making, that no other satellite will have done so far, at least not at a global scale. One aspect I’m interested in is just exploring the data, looking for basic things that will be useful for our understanding of aerosols and clouds and the climate in general.
I have some pet projects that I’ve always been interested in, for example a specific situation when aerosols are lofted above clouds. Aerosols are generally something that cools the climate because they reflect light. But if you have, say, a dark smoke aerosol on top of the cloud, it actually warms the climate, because it absorbs some of the energy that would have otherwise been reflected into space. So that’s something we’ll be able to do with PACE that we don’t really have great observations of now.
What is your favorite color and why?
I have a 10-year-old daughter, and favorite colors are very important to her and her friends. They’re always asking me what my favorite color is, and I say I can never answer them because how can you like one color without liking all the others?
Do you have a favorite type of cloud or weird atmospheric phenomena?
There’s also an optical phenomenon called glory. If you’re floating above a cloud and the Sun is behind, you look down at your shadow and you will see your shadow with a glory around it, which is like a circular rainbow around yourself. That’s one of my favorite optical phenomena.
What’s a fun fact about yourself? Something that a lot of people might not know about you?
Kirk Knobelspiesse working on the NASA P-3 during the ORACLES field campaign in São Tomé, São Tomé and Príncipe. Image Credit: Andrzej Wasilewski
I’ve been to latitude zero, longitude zero, the point in the South Atlantic Ocean where the equator and prime meridian intersect. It was part of the ORACLES field campaign. There’s nothing special there. It’s just ocean – and I don’t mean to offend my oceanographer friends by saying it’s nothing special – but there was no pillar of fire or something like that.
What advice would you give to aspiring scientists looking to get where you are today?
Don’t pigeonhole yourself into one discipline or one topic of study. Not just computer science or physics or oceanography. They’re human constructs, sociological constructs, and they don’t have anything to do with nature, other than how we have organized ourselves. A lot of where I’ve found interesting and productive things to do have been at the boundary between disciplines, or learning from one discipline and applying that approach to another discipline. So, don’t tell yourself, “I can’t do something because I’m not trained to do that.” You can learn and you can train yourself, and don’t be afraid to go out on a limb and do something you don’t really know how to do.
What is one catch-all statement describing the importance of PACE?
We will be making use of things that people cannot see – the nature of light – to understand things that we can’t otherwise observe.
Header image caption: Kirk Knobelspiesse hiking at Rachel Carson Conservation Park in Brookeville, Md. Image Credit: Barbara Balestra
By Erica McNamee, Science Writer at NASA’s Goddard Space Flight Center
Whether in plants or animals, greenhouse gases or smoke, carbon atoms exist in various compounds as they move through a multitude of pathways within Earth’s system. That’s why NASA’s Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission – scheduled to launch in January 2024 – was designed to peer down at Earth from space to see those many forms of carbon in a way no other satellite has done before by measuring colors not yet seen from the vantage point of space.
“PACE is standing on the shoulders of some giants, but previous and current satellites are limited in how many colors of the rainbow they can actually see,” said Jeremy Werdell, project scientist for the PACE mission at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
Although one of the primary goals of the mission is to measure the colors on the ocean surface, in the 420 miles (676.5 kilometers) between PACE in orbit and sea level are parts of the complex carbon web that the satellite will also be able to monitor.
The connection between major wildfires and the subsequent explosion of phytoplankton production is an example of the events NASA’s upcoming Plankton, Aerosols, Clouds, and ocean Ecosystem (PACE) mission will help investigate. PACE’s suite of instruments will allow scientists to get a clearer picture of carbon as it links land use and fires, atmospheric aerosols and marine communities. Credit: NASA’s Goddard Space Flight Center
Atmosphere
From PACE’s location in space, one of the nearest forms of carbon to detect could be the wispy plumes of smoke and ash rising into the atmosphere from fires. Carbon is a key building block of much life on Earth, including plant life. When burned, the vegetation’s carbon-based molecules transform into other compounds, some of which end up as ash in these plumes.
The instruments on PACE will be able to monitor these smoky clouds, as well as other atmospheric aerosol particles, measuring their characteristics including the relative amount of smoke in different places. Combinations of these measurements made by PACE’s two companion polarimeter instruments, SPEXone and the Hyper-Angular Rainbow Polarimeter-2 (HARP2), and the detailed color measurements of the smoke made by the Ocean Color Instrument (OCI) will also help scientists identify what was burnt.
“Each instrument brings something different,” said Andy Sayer, PACE’s project science lead for atmospheres at NASA Goddard. “Putting them all together though, you’re getting the most information.” Sayer is also a senior research scientist for the University of Maryland Baltimore County.
These measurements help scientists understand more about the balance between the incoming energy from the Sun, the outgoing energy from Earth, and where it may be absorbed in between by things in the atmosphere like these smoke plumes. Even at a local level, PACE can provide information about how smoke affects air quality, impacting communities that may be near fires.
Land
Peering through the smoke particles and other aerosols, PACE can also tell us about the health of terrestrial plants and trees. Even after a devastating wildfire, fresh green plant life begins to grow and thrive. With more spectral bands and colors to see from the upcoming satellite, scientists will be able to understand what kinds of plants are recovering from fires over the years.
“In a time where we’re experiencing unprecedented climate change, we need to be able to understand how global vegetation responds to its environment,” said Fred Huemmrich, research associate professor at the University of Maryland, Baltimore County, and a member of the PACE science and applications team.
PACE will be able to monitor the different shades of colors in vegetation, and plant color can be an indicator of health. Just as house plants begin to fade to yellow if they haven’t been watered enough, plant life around the globe changes color as it experiences stress. Healthy plants take up carbon in the form of carbon dioxide as part of photosynthesis, while unhealthy plants that can’t complete photosynthesis leave the carbon dioxide roaming around the atmosphere. Given that carbon dioxide is a greenhouse gas, these measurements also play a significant role in understanding climate change in greater detail.
By measuring a full spectrum of color, PACE will view tiny changes in pigment to detect how plants are responding to stressors, helping scientists learn whether they are utilizing the surrounding carbon or not. Previously, these colors were primarily viewed in field studies of specific areas. Stressors like droughts were inferred using weather data, but covering large expanses was difficult.
“For the first time, we’ll really be able to look at changes in the health of plants over the globe,” Huemmrich said. “It will dramatically improve our understanding of how ecosystems function and how they respond to stress.”
Ocean
From plants on land to organisms in the ocean, PACE will view the expanses of water on Earth to measure phytoplankton – the P in its name. With its ability to measure a wide spectrum of colors, PACE will now not only be able to see more across the surface of the ocean but will also help scientists differentiate between phytoplankton species.
“It’s like you were making a painting with really coarse brushes, and now you have thin, fine brushes that help explain so much more in greater detail,” said Ivona Cetinić, an oceanographer in the Ocean Ecology Lab at NASA Goddard.
Phytoplankton, small organisms that live on the surface of the ocean, play a critical role in the food chain and the global carbon cycle. Each type of phytoplankton provides a different pathway in that expansive web of routes that carbon can take, all depending on the characteristics of the plankton. One pathway may lead to the carbon becoming food for a larger species, while another may lead to carbon becoming waste, sinking deeper into the ocean.
Scientists conducting field work have found that types of phytoplankton vary slightly in color and have identified these phytoplankton on small scales. PACE’s ability to measure a full spectrum of color will help scientists tell the difference between phytoplankton on a global scale by seeing more of these colors, deepening the understanding of carbon pathways and quantities.
Though one of PACE’s key goals is to view the ocean, its line of sight looks over the atmosphere and land as well. With these expansive observations, and the massive quantities of data collected, PACE provides the ability to see in what ways the atmosphere, land, and ocean are connected, including with the complex web of carbon pathways.
“I’m energized for this opportunity for discovery that this observatory is offering,” Werdell said. “I have every expectation the world is going to do great things with these data.”
By Erica McNamee, Science Writer at NASA’s Goddard Space Flight Center
NASA’s PACE mission, which will provide a major boost to scientists studying Earth’s atmosphere and ocean health, completed a milestone test in October at the agency’s Goddard Space Flight Center in Greenbelt, Maryland.
The Ocean Color Instrument (OCI) on the Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission passed thermal vacuum tests to ensure it can withstand the harsh space environments.
As we prepare the Plankton, Aerosol, and cloud Ecosystem satellite for launch, we’re gathering all the ingredients, um…instruments, and baking ourselves a fresh new satellite. Credit: NASA’s Goddard Space Flight Center/Scientific Visualization Studio. Video descriptions available.
PACE will view the atmosphere and ocean surface from space. While highly useful for studying atmospheric aerosols, OCI is specifically designed to look for small aquatic organisms called phytoplankton that can be so numerous they influence the colors of the ocean. Phytoplankton play a large role in the ocean ecosystem — not only are they food sources for larger species, but they also convert carbon dioxide into organic matter through photosynthesis, playing an active role in moving carbon from the atmosphere into the ocean.
The PACE mission will help scientists learn more about the relationships between phytoplankton and the surrounding environment by measuring how light reflects off the ocean and through the atmosphere. Scientists can see these organisms in the ocean using satellites, but currently can’t differentiate the phytoplankton by type easily. Identifying types of phytoplankton help scientists to detangle some of the complex ecological systems in the oceans.
“When you look down at the ocean, you can see phytoplankton there and for the first time, with PACE, the scientists will be able to see what type of phytoplankton there are from space,” said Gary Davis, mission systems engineer at Goddard for the PACE mission. “Hopefully this mission will be able to communicate the importance of ocean health and the health of plankton to the whole world.”
To ensure the satellite is ready to gather this data, engineers put the satellite through, well, its paces. The thermal vacuum test that was just completed reduces atmospheric pressure as close to the vacuum of space as possible and then cycles through a wide range of temperatures. During the sunlit part of a spacecraft’s orbit, it can get very hot, up to approximately 50 degrees Celsius (122 degrees Fahrenheit); at other parts of the orbit, zero solar exposure means extremely low temperatures, as low as -90 degrees Celsius (-130 degrees Fahrenheit).
OCI, which was built at Goddard, can measure light in a multitude of colors, far more than previous satellites that share its frequent global coverage. Light variation by wavelength, the character of light by which it is defined, provides the color we see. OCI can detect a continuous spectrum of different wavelengths of light, and can even see colors beyond what the human eye can detect. By detecting more wavelengths, the instrument will allow scientists to tell the difference between types of phytoplankton from space. This is helpful in understanding the pathways of the carbon cycle in the atmosphere, land, and ocean, and characterizing the phytoplankton as harmful or helpful.
“OCI is really a stretch of the state of the art of what we can do right now,” said Davis. “It’s probably the most advanced thing we have on the observatory.”
Former ocean-observing satellites had the ability to measure light at a small set of wavelengths through the development of multi-spectral instruments. OCI has the ability to measure color continuosly at many ultraviolet, visible, and near infrared wavelengths, also known as hyperspectral imaging.
The previous missions can be imagined as a regular 8-color box of crayons, said Jeremy Werdell, project scientist for the PACE mission. Though still highly valuable for creating a complete picture, there are gaps in between the shades of colors. For PACE, OCI can be imagined as a 128-color box of crayons, filling in those gaps using smaller and continuous intervals of wavelengths.
“With all of the colors of the rainbow here, most of us don’t know what we’re going to discover, because we’ve never had that chance on global scales,” Werdell said. “It’s the only mission planned at NASA or elsewhere that provide global hyperspectral, full colors of the rainbow everywhere, everyday.”
When light from the sun reflects off the ocean, that light has already traveled from the sun, through the atmosphere – clouds and aerosols that compose Earth’s atmosphere – and water before it reaches the plankton in the ocean. The light then bounces off the plankton and travels back through the water and atmosphere again. The light that makes its way through all those stages can tell a story through color but still needs to be analyzed and accounted for any atmospheric effects, which is where the polarimeters on PACE come into play.
The Hyper-Angular Rainbow Polarimeter 2 (HARP2) also recently completed TVAC testing, earlier in September. The instrument is one of two multi-angle polarimeters on PACE, which act as polarized sunglasses for the spacecraft, measuring how light bends as it travels through the water droplets, clouds, and aerosols in Earth’s atmosphere, informing scientists more about their physical properties, as well as providing another source of color measurements. HARP2 was built at the University of Maryland, Baltimore County.
SPEXone, the other multi-angle polarimeter, was built in the Netherlands by engineers from SRON Netherlands Institute for Space Research, Airbus Netherlands and NASA. Each of the three instruments will be integrated into the spacecraft as they complete their individual tests – and in fact, OCI was just lifted onto the spacecraft on November 21.
“We have an observatory!” said Werdell.
As the timeline of events for PACE ticks on, the days are being counted down, all leading to the launch scheduled for early 2024.
