August 2008 – Mission to Hubble

Science Instruments – Repair vs. Replace

Recently, several people asked: Why not replace the two instruments we’re repairing with new ones and why can’t we take the two science instruments inside the Shuttle and work on them there?

This is such an excellent question! The answer is truly an engineering marvel, so thank you for asking.

Hubble’s instruments were designed for easy removal and astronauts have removed radial and axial instruments on previous repair missions to Hubble. So, why aren’t we doing the same thing this time? Time is the answer.

The most valuable commodity on-orbit besides the astronauts themselves is the astronauts’ time. Every second of their time is choreographed more closely than an Olympian’s gymnastic floor exercise. Just as the gymnast’s every motion is fixed in her or his mind, the astronaut’s every motion outside the Shuttle is practiced so that a moment is not wasted.

When the spectrograph, STIS, failed, engineers led by Mike Weiss at Goddard, looked at every possible way to fix it, including the ones you’ve mentioned such as bringing it into the Shuttle Cargo Bay. But Mike found that “this approach would have taken about 2 additional hours of EVA time and would have required additional hardware to serve as a work bench. Pulling out the entire instrument would also mean overcoming potential contamination and electrostatic discharge concerns.”

I can’t resist taking this opportunity to talk about the symbiotic relationship between humans and their almost-robotic tools one more time! The NASA engineers surmounted yet another hurdle with tool design. If you’ve pulled electronics boards out of your computer, you’d think it might be pretty easy to do on-orbit. But Hubble has something called “wedgelocks” to make sure the electronic boards don’t rattle around on-orbit and so that there’s a path for heat to sneak out, keeping the boards cool. Imagine how frustrating it would be to pull out a stubborn electronics card in bulky gloves on Hubble! Resorting to swearing is usually the path we earthlings take on the ground. Somehow, it always helps, but it won’t help much on-orbit with Hubble.

So, NASA developed an extraction tool to neatly pull out a board. That tool was tested with the most stubborn test board ever made, and came out with flying colors and little debris.

Now that we know how to gain access to failed cards inside the instruments, pull them out and replace them, and put on a new simple cover, our marriage between tools and humans is complete. As Mike joked, the Hubble commercial might go like this: EVA Set-up — 3 hours. Pull and replace failed electronic cards — 15 minutes. Resurrect Science — Priceless.

Here’s Mike Massimino practicing with the mini-power tool working on a test article.

I just love getting questions like this one that help us all think about the science and engineering marvels we’re creating today. I only wish I could start my career all over again and see what the next 30 years bring.

Colleen

From Gobies to BBots – – Part II

We left patient Hubble last week with a few unanswered questions. We rejected the folly of a human being-robot competition and embraced the need for a cooperative marriage, if not from love, then from convenience, between humans and robots. Now, let’s meet someone at Goddard who designed the surgeon’s robotic tools those astronauts will use on our patient.

In this brave new world, the engineers at NASA’s Goddard Space Flight Center joined with astronauts and engineers from Johnson, Kennedy, and Glenn, among others, to develop the robotic tools required for Hubble repair. There are about thirty-five engineers at Goddard who have designed more than fifty tools ready for use on this fifth and final mission to Hubble. These tools are not usually thought of as “robots” but they are a step along the evolutionary path to robots in space.

One man has been designing Hubble repair tools for the last four years – – Justin Cassidy, Crew Aids and Tools Lead Systems Engineer. What are his favorite tools of all time? Not even needing a moment to consider, Justin said “My clear favorites are the two tools that make the STIS or Space Telescope Imaging Spectrometer surgery possible: the mini-powertool (power screwdriver) and the fastener capture plate.”

Without the high-speed, low-torque power mini-powertool (210 rpm +/- 30 rpm with up to 5 ft-pounds of torque), accessing 1 of 13 printed circuit boards inside of STIS would be incredibly difficult and worse, time-consuming for the astronauts.Now, the 111 screws holding down the cover of STIS can be removed by an astronaut in about 20 minutes.

As Justin put it “We humans control the evolution of our tools, and the Goddard Space Flight Center has stepped up the pace of that evolution for this last Hubble repair mission. We have created many tools to make never before repairs to instruments.”

But NASA employees are not satisfied until the best evolutionary path is found. Qualifying (testing) a new tool in space is a necessity. The battery and electronics for the mini-screwdriver must withstand the harshness of space because of the extreme temperature fluctuations and airless environment. But after Justin and his group surveyed industry to find a battery for the mini-powertool, they realized the solution was in their own back yard. Goddard had designed the PGT or Pistol Grip Tool for the first Hubble repair mission in 1997. It was a low speed, programmable high-torque power screwdriver and its battery was already flight qualified. Reusing the PGT battery for the mini-powertool saved both money and time for the team.

Justin’s next favorite tool is the smartly designed fastener capture plate. Those 111 screws need to be secured somewhere so they don’t float around after they are removed. The fastener capture plate has a place for each screw, neatly color-coded in red-white-and-blue, yet see-through, so the astronauts can easily see what they’re doing. Goddard called on experts in material coatings from GSFC and the Glenn Research Center to make sure all the materials used on the plate and see-through windows could withstand the thermal extremes in space and that the material wouldn’t “outgas” or release contaminants while used inside HST. Outgassed material can be a major source of contamination, something every kid with a telescope on the ground knows would ruin her telescope mirror and along with it, her images.

Of course, you don’t want the surgeons to stitch up the patient by putting back all 111 of those carefully captured screws, inefficiently using valuable EVA time. The engineering solution to this problem is not straight-forward. The cover to STIS provides an avenue for heat to leave the instrument and go out into space and this capacity is essential to the thermal control of the instrument itself. So the engineers at Goddard developed a nifty cover that provides the thermal conductivity while it easily snaps into place on top of STIS with two large latches.

Although Asimov and other heroes of science fiction can take you to the future, for now, Robots have no independent thought, no independent soul from their human being masters. Today, they are hand-held tools. Tomorrow, there will be a marriage between beings and robots — something that might be called Being-Bots or BBots.

So we have now gone from symbiotic Gobies and their interspecies mates (see August 13th blog), to BBots, joining beings and robots in a quest to explore outer space.< The gap between fact and science fiction is collapsing.

I hope you’ve enjoyed this journey into Hubble repair mission 4 tools and how they are one small step on the evolutionary pathway to robots and humans working together in space.

Colleen

Ground Support Personnel Practice for Last Mission to Hubble

Introduction

I am the HST Development Project Scientist, responsible for ensuring all new hardware developed for SM4 meets its scientific goals. I am also the Instrument Scientist for the Wide Field Camera 3. The HST Project developed this facility instrument on behalf of the astronomical community and as such has no principal investigator. We have a local science team that is responsible for dealing with day-to-day issues related to the instrument’s scientific performance and for carrying out its ground calibration. In addition, an external Science Oversight Committee, chaired by Prof. Robert O’Connell of the University of Virginia, represents the broader community and provides overall guidance regarding scientific matters. I have a BS in Physics from the Massachusetts Institute of Technology, Cambridge, and a Master’s and Ph.D from the University of California, Berkeley also in Physics.

21 August 2008

9:00PM. Just arrived at Johnson Space Center for the Servicing Mission 4 JIS (Joint Integrated Simulation) #5 – “Joint” because it is supported by both Johnson, lead center for space shuttle on-orbit operations, and Goddard, lead center for HST (Hubble Space Telescope) operations. Just as the astronauts must practice repeatedly for the mission, so must the ground support personnel. The mission is short, and the time during the 5 scheduled spacewalks is particularly precious. It is therefore necessary for experts on all shuttle and HST systems and procedures to be on console to address any problems as they arise – with round-the-clock operations, there ends up being hundreds of people who support the mission.

My station is in the Blue Flight Control Room (FCR), or as we call it, the “blue ficker”, at JSC with some other HST personnel (more HST personnel are stationed back at Goddard). Shuttle ops are controlled from the White Flight Control Room down the hall. Upstairs is another large room with many other HST support personnel monitoring various hardware subsystems. Also upstairs in this same building is the old Apollo control room – “Tranquility Base here, the Eagle has landed…”, “Houston, we have a problem…” – a goose-bump-raising site that we have all visited when not on duty.

From left, Randy Kimble, David Leckrone, Preston Burch (all from GSFC), Matt Mountain (STScI), Mike Kienlen and Keith Kalinowski (both from GSFC) at a management console during the joint integrated simulation at JSC on Aug. 21.

As Instrument Scientist for the new Wide Field Camera 3 (WFC3), I am particularly eager tonight to see how the functional test of the newly installed instrument goes (the Simulation, or “sim”, picked up this evening a few hours after the astronaut installation of WFC3 on the first EVA – Extravehicular Activity – day). WFC3 has two observing channels – the ultraviolet/visible (UVIS) channel can be checked out pretty well, even though the Charge-Coupled Devices (CCDs) will not be fully cooled until several weeks after release of the telescope; for the infrared (IR) channel, we can check out the electronics, but the detector is much too warm during the Servicing Mission to yield any actual imaging data.

22 August 2008

3:00AM. Success! WFC3 has passed its functional test! Both channels look completely nominal. There is one small telemetry issue – looks like a bad readout on a temperature sensor – but nothing that should impair operations. A good feeling in Sim land, and we’re all hoping for the ecstatic feeling of equivalent success in the real servicing mission functional test that should be happening a mere seven weeks from now!

The main issue for the rest of the night will be some forward planning of the upcoming EVAs – there is a simulated problem with the rotator that orients HST properly so that the work site to be serviced faces the crew cabin; this means that the telescope will have to be manually rotated at the beginning and end of each day’s EVA at the cost of a significant amount of EVA time. We’ll have to give up something in the planned timeline for each day, so there is a lot of discussion of the various options, based on the priorities that have been set for the various mission elements (the new hardware and the STIS – Space Telescope Imaging Spectrograph – and ACS – Advanced Camera for Surveys – repair tasks) and the logistics of how things pack into a given day’s activity. It appears that it will basically come down to a choice between repairing ACS and installing a new Fine Guidance Sensor. Sad to lose one, but most of the mission content can be retained.

Hubble's 100,000th Orbit

Today the Hubble Space Telescope will be orbiting the Earth for the 100,000th time!

To celebrate this special milestone, I have actually submitted a proposal, for the telescope to observe NGC 2074, a star-forming region in our neighboring galaxy, the Large Magellanic Cloud. From previews of that region, taken by ground-based telescopes, I am expecting the image to be quite spectacular, but we will not know for sure until the data are in hand, and the image has been properly processed.

Usually, when the odometer in your car shows 100,000, you know that this may be the time to buy a new car. With Hubble things are very different. During the servicing missions, the astronauts not only make necessary repairs, they also install entirely new instruments. In terms of its discovery potential, Hubble after Servicing Mission 4 will be the best it has ever been. In other words, this coming fall, Hubble’s 100k something orbit, will only be the FIRST orbit in the life of the new Hubble.

The image of NGC 2074 has now been published. Read the full press release

This nebula, imaged by the Hubble Space Telescope on August 10, is about 170,000 light-years away. Credit: NASA, ESA, and M. Livio (STScI)

From Gobies to BBots: Hubble's Marriage of Convenience

Could the lack of one thing make this Hubble repair mission impossible? Kaput, never to be? All that would remain for us is a deep sigh and a heartfelt wish to see more beautiful, yet unattainable, pictures of stellar nurseries and sudden, cataclysmic stellar deaths, extra-solar planetary atmospheres, and an exploration of dark energy, the mysterious force pulling our universe apart. Discoveries that would forever change how we see ourselves and our universe now wouldn’t be made. What intense problem would bring work on this last repair mission to a standstill? Politics? Inter-NASA Space Flight Center squabbling? A sudden need for swollen bags of money in a time of national crisis? Additional visits from FBI agents intent on reviewing minutiae while frightening young interns?

None of these answers even come close. Instead of rounding up the usual suspects, we humans must first come to grips with the reality of outer space. We want to conquer new worlds, to expand our sphere of influence and accomplishment, moving ever wider into our environment as victors in our solar system. Yet this homocentric universe view doesn’t even succeed in our nearest neighborhood, low-earth orbit, where we have placed Hubble. We humans are incapable of executing the intricate surgical repair plan for Hubble without serious outside help – robotic help.

Humans have visited Hubble four other times. During these visits to our on-orbit patient, internal surgery was only timidly attempted once. That’s when astronauts John Grunsfeld and Richard Linnehan successfully replaced the power switching station and its rat’s nest of cabling and connectors on Hubble in March 2002.

Major surgery is now required on patient Hubble. For the first time ever, we need to probe the guts inside in order to improve our patient’s remaining, productive days. One of those early surgeons, John Grunsfeld, will be returning to Hubble to perform this more invasive surgery.

The two instruments being cracked open on repair mission 4 are not designed for on-orbit repair. Back in the 1970’s and 80’s, we just couldn’t conceive of astronauts performing even minor internal surgery, so we didn’t build in the capability. In the relentless and unforgiving vacuum of space, human beings alone are just not up to the task, so it didn’t seem possible.

A technician tests the new mini-tool with the new
capture plate on the screws in the mock-up of the
Space Telescope Imaging Spectrograph (STIS).

But we can do it with a partner, a marriage of convenience perhaps, but one which comes to the rescue. Robotic tools, fifty new ones to be exact. Although we’ve used tools before, advances in these fifty new tools are akin to advances from an 18^th century barber-butcher-surgeon to our 21^st century neurosurgeon.

The human being-robotic relationship (or being-roBots – – BBots for short) we are entering is akin to the beneficial symbiotic relationships commonly found among species on our Earth. Beneficial symbiotic relationships are ones in which plants or animals of different species depend on one another for survival. For instance, snapping shrimp and gobies live together in the same burrow on the ocean floor. The blind shrimp rely on the goby’s intruder warning alert to keep them safe, while the shrimp keep the burrow clean of parasites. There are thousands of other examples to be found on Earth.

Two yellow clown gobi fish and a shrimp near a small burrow in the sea floor.

The Yellow Clown Gobi and shrimp help each other
in their shared burrow.

In the case of Hubble, let’s see why the on-orbit repairs require a similar symbiotic relationship between the astronauts and the robotic tools. Let’s say you have a spectrograph on your lab bench. It is used to split light into all the colors of the rainbow for you, revealing information about its origin, temperature, and chemical makeup.

Now, you’re technically savvy, so you’ve discovered that one printed circuit board within your spectrometer contains a faulty power supply unit, making your beautiful spectrometer dead as a door nail. To add to your task, you have a second instrument on your bench, a camera, and it, too, has a failed power supply unit on one PCB. What would you do? Well, you’d just fix it, right? You’d simply open up the instruments, pull out the faulty boards, replace them with good boards, and put the instrument back together. Easy.

But now things get hairy. Your two instruments are placed in the deep end of a pool. And for the first time ever, these instruments are not designed for you to easily open them and get to the faulty cards while you and they are submersed in water.

So, you’re suited up in scuba gear and dumped into the deep end of the pool in order to perform these tasks under variable lighting, going from adequate to hazy. Oh, and of course you don’t want any of the 143 screws you’ve removed from these two instruments to float away. And you wouldn’t really want to put all those screws back in as you closed the two instruments up. As a diver, I know what would happen to me. With all these obstacles and things to think about, I might suck down all the air in my scuba tank!

Now would be the perfect time to reject the folly of a human being-robot competition and embrace the need for a cooperative marriage, if not from love, then from convenience.

Next week I’ll talk to the tool-master at Goddard, Justin Cassidy. He’ll reveal his favorite tools of all time for the Hubble repair mission.

What next? As Mr. Mordecai Albert says on his August 3rd comment, we all thirst for additional information on Hubble’s contributions to our knowledge of the cosmos.

So my follow-on column will focus on the amazing scientific discoveries – -those “Aha” moments — brought to us by Hubble. I’ll visit the Space Telescope Science Institute and bring you directly to the scientists themselves. I’ll also continue the saga of the young intern and the FBI agents.

Keep those comment coming! It’s a pleasure to have the opportunity to talk to people this way.

Colleen

Pieces of the Puzzle

Since I last wrote, the crew of STS-124 successfully completed their mission and returned to earth. Translation: we’re up next! The team here at Goddard couldn’t be more excited—two weeks ago, we shipped 3 of our 4 carriers (those are the large building blocks that make up the payload for STS-125) to Kennedy Space Center and have begun the process of integrating our hardware to the shuttle’s payload bay.

It’s really hard to believe how much time, effort, and energy goes into preparing for a launch. There are so many people that need to work together in order to make things “go”; from the folks who design the parts to those who run the final checkouts, everyone’s role is important to the success of the mission and program in general. I was thinking about this the other day—in my day-to-day life here at Goddard, I interact with upwards of 20-30 people beyond a casual “hello” in the hallway….and that’s just the folks working on one sub-system! When you propagate that number over a vehicle the size of the space shuttle that contains thousands of subsystems, you really get an appreciation for just how big this all really is.

As the launch gets closer, this team has really come together to meet all of our goals. I won’t lie—the hours and days are getting long for all of us right now; but we’re coming down the home stretch. Systems are coming together, final rounds of testing are being completed, and piece by piece, our hardware is coming to the end of its preparatory journey. Over the last two and a half years working here at Goddard, I’ve gotten to see several of these designs go from initial concepts on a meeting room whiteboard to a physical systems that I’ve gotten to help build and test. To see everything come full circle like this has been absolutely incredible.

Lately, my part of the “circle” has been to support the last of our testing efforts….a process we affectionately refer to as “shake and bake”. Space is a pretty unforgiving place – the launch/landing loads and temperatures experienced once on orbit are far greater than those you’d see in your day-to-day life here on Earth. Because of this, we need to perform a variety of tests in order to qualify the hardware for flight. We develop plans—similar to a lab report you’d write at school—outlining the test we’d like to perform, why we’d like to perform it, and what we expect to happen. From there, we shake, pull, push, heat, and cool the system until we’re certain that it will behave the way that we expect it to. This often results in getting to perform some pretty neat, hands-on activities in order to get the measurements that we need. For me, this is probably one of the most exciting parts of my job.

So what’s up next? After I finish my work here in Maryland, I’ll be headed down to Kennedy Space Center to help with payload integration work. NASA’s already started an official web site documenting our team’s efforts at the Cape. You can check it out here: http://mediaarchive.ksc.nasa.gov/search.cfm?cat=180

Until next time (from Florida!).

Dream BIG!
Meg

Introducing Blogger Megan Meehan

Hello, my name is Meg and I’m a member of the team of engineers helping to prepare for STS-125—the fifth and final Hubble Servicing Mission. Over the next few months, I hope to give you some insight into my job at the Goddard Space Flight Center as well as to share some general information about the mission itself.

While I’m an aerospace engineer by education, my official title here at Goddard is mechanical systems engineer for the Orbital Replacement Unit Carrier (ORUC). I help to ensure that all of the pieces of the ORUC—roughly a third of the shuttle’s payload for this mission—fit together properly and function in the way that they’ve been designed. Day to day, my job is rarely the same (which is exactly how I like it!) since I’ve been able to get involved in all phases of hardware design, development, and testing.

I hope to update this blog at least once a month. Feel free to leave any comments or questions and I’ll do my best to answer them.

Until then, dream big!

-Meg

This blog can also be viewed on the Challenger Center web site.

Introducing Blogger Dr. Mario Livio

picture of Dr. Mario Livio

I am Dr. Mario Livio, an astrophysicist at the Space Telescope Science Institute (STScI) in Baltimore, MD, Head of the Office of Public Outreach, and an author of popular books on science and mathematics. I have been at the STScI for seventeen years. I am definitely what has become known as a “Hubble hugger” – passionate about the Hubble Space Telescope and its achievements. Through this blog, I hope to bring my personal observations about the upcoming Hubble servicing mission and what it will mean to astronomers, the general public, and myself.

In 2000, Time Magazine chose Albert Einstein as the “Person of the Century.” Some people were surprised that a scientist was chosen over world political leaders, authors, artists, and economists. I wasn’t. Einstein’s achievements have crossed the boundaries between science and culture, and have penetrated into every area of human intellectual endeavor. Just enter “Albert Einstein” at the Amazon.com webpage and you’ll find more than 35,000 results. Einstein changed our view of the universe in a fundamental way.

The Hubble Space Telescope has SHOWN us Einstein’s universe. And when I say “us” I don’t mean just the scientists. Hubble has literally brought the wonders of the cosmos into homes worldwide. You now find Hubble images not only in astronomy textbooks, but also on the covers, variously, of a book of music for the trumpet, a German art magazine, a book that teaches English to Japanese children, and an album of a rock group. And here comes the best part. After eighteen years of operation, Servicing Mission 4 can bring Hubble to the richest moment in its life in terms of scientific capability!

Sometimes people ask me if I don’t feel depressed by the apparently diminishing role of humans in the universe. After all, we are not at the center of the cosmos, or even the center of the Milky Way Galaxy. Even the stuff of which we are made is only four percent of the matter in the universe, and everything we can observe is but a speck of all there is. But notice that the apparent decrease in our physical presence is only a consequence of the tremendous increase of our knowledge. And Hubble played a crucial role in that expansion of our horizons of understanding. I am truly proud to have been a part of this incredible scientific adventure called the Hubble Space Telescope, and I am looking forward to an even brighter future.