Interview: Catherine G. Coleman|
A couple of weeks prior to scheduled launch, STS-93 Mission Specialist
Catherine G. Coleman took some time out from training to answer questions about the mission.
Click on the image to hear Catherine's greeting.
Cady, it was early last year when you got the word of your assignment to your second space shuttle mission, about two years after you'd finished your first; what was your reaction when you learned you were going to get another chance to fly?
This was not actually my first experience with the Chandra X-ray Observatory, and so I thought that being assigned to this space shuttle flight was meant to be. I had actually, in the course of doing some other parts of my job, met the folks that ground the mirrors for the Chandra X-ray Observatory and got to give them an award for the incredible job that they did making these state of the art mirrors. I also visited Kodak where they assembled the entire telescope. This was new for me, to learn about this amazing telescope that was going to be launched in just a few years and teach us about the universe. Suddenly I was assigned to the mission, and I thought, "You know, I'm supposed to do this."
We're going to talk in some detail about looking at x-rays in the universe. Before we do, though, let's talk first about the astronauts involved-you. Why did you want to be an astronaut in the first place?
I'm not one of those kids that wanted to do this ever since they were six. It took me quite a bit longer. I was in college when I went to a talk by Dr. Sally Ride, who was the first American woman astronaut. I listened to what she had to say and realized that this was the job that I wanted. I was really able to see someone that I could identify with. She really seemed like a neat lady, and she had a job where her education seemed to count. She also got to do some educating. I'm not nice enough to do it every day, but I really do enjoy teaching. She also got to go to space and fly jets and I thought, "What more could a chemist want?"
Let me back up one step. What was it that made you want to be a chemist?
Chemistry is something that I always liked, and I had a high school teacher, Mrs. Aup, who was so fascinated by it and made it so interesting. I realized later, when I took courses in college, that I hadn't really understood anything that she said. I just wanted to know how the things that she talked about actually worked. It was just the kind of jigsaw puzzle that I liked.
Who were some of the other special teachers you had, in high school or in college, that had that kind of positive impact on you?
There are a lot of different teachers that give you help or advice along the road, and each of them makes a difference. It's always something they do that makes you think that they believe in you and gives you the confidence to go on and keep doing other things. I once tried to get a job doing undergraduate research for a very well-known professor at MIT, and he said, "Tell me why I should let you work in my laboratory, because I'm not sure you're actually going to accomplish any research that I need done." I answered, "I'm a student at this university. It's my job to get educated and part of your job to help me get there. I think I'm going to learn a lot in your laboratory, and hopefully I'll go on and use that someplace where it's valuable to everybody else. I think you should give me a job." I got the job. The fact that this very famous man gave me a job really increased my confidence and [I] said, "Boy, maybe I should be a chemist."
On this mission, you're flying with a Commander who has been the focus of a great deal of public interest as the first woman ever to command a space shuttle mission. How's Eileen Collins been doing dealing with all of that attention while trying to keep you and the rest of your crewmates on course to fly the mission?
She doesn't seem to have any trouble keeping the rest of us in line. Eileen's background is with large airplanes, which also have large crews. She has years of experience with working with a team of people and realizes that everybody on the team has different needs and different things that are important to them, and she also realizes there are probably different ways to guide each of them. I can see that background in Eileen, and she takes really great care of us. In terms of dealing with the attention, getting ready for a mission is so busy that you don't really have a lot of time to pay attention to that.
All of the science on your mission aside, it will still be an historic since it is the first time that a woman has commanded a mission in space. In your opinion, what's the historic significance of having a woman in this job for the first time?
There are a lot of little girls out there that will see Eileen Collins' photograph in the newspaper and on TV. They're going to hear about her for days and days. I'm really hoping that they realize that this is a job that they could have. When they see Eileen, they see someone that they can identify with, someone who looks like their mom. Maybe they will realize that their mom has more potential than they thought she did. It's really important for our kids to have these kinds of goals. I think that for women and minorities, sometimes you need a really obvious example to make that point. Eileen flying as the Commander on this mission will make that point.
The target launch date for this mission has moved a couple of times due to delays in preparing the primary payload or with other associated hardware. How have you and your crewmates been able to put the extra training time to good use?
This mission is a standard mission for NASA. They have launched a number of satellites and other different things on an Inertial Upper Stage. We thought it would be a fairly straightforward mission to prepare for. I'm actually glad that we've had this extra time. The Chandra X-ray Observatory is a little different than some of the other payloads. It was built over a period of years and it's a very delicate kind [of] structure. It would be very difficult to bring Chandra home if we got up to space and found out that we couldn't deploy it. We've actually spent that time really thinking about the different problems that could happen, and whether they will affect our ability to bring Chandra home or to deploy Chandra. That time's been very well spent here at home.
The most recent delay was caused by the failure of an Inertial Upper Stage rocket during an unrelated satellite deployment in April. You are using an IUS to deploy your payload on this mission. Can you tell us what was the cause of the failure on the April satellite launch, and why you're confident that the IUS that you're going to be using is going to perform properly this time?
The Inertial Upper Stage, or the IUS, is a two-stage rocket. That means that there's one part of it, the back part of it, that will burn and break away, and the front part of it will burn. Oftentimes, this is used to bring satellites into what we call a geosyncronous orbit; so if my fist is the Earth, then these are going to be very far away from the Earth, whereas we in the shuttle are fairly close to the Earth. In the case of Chandra, this Inertial Upper Stage is going to be used, not to put it in a giant circular orbit, but into a giant elliptical orbit, and so it's very important that both those stages fire. What happened on that other mission was that the first stage fired, but did not separate completely. From what I understand from the Air Force investigation, they've found something that was done differently on that mission. They have already looked at our Inertial Upper Stage and seen that it has not been done in the way that was basically wrong. I have a lot of confidence that we'll be flying soon.
Each of us has mentioned a couple times the word "Chandra." That's the primary payload on this mission. It's been described as "a highly sensitive x-ray telescope, which offers scientists a greater understanding of the forces that created the universe and continue to shape it." Can you give us a quick lesson on what an x-ray telescope is? Why are astronomers interested in having a telescope that looks at x-rays?
Astronomers are interested in looking at the whole universe, the whole spectrum. They'd like to see everything that is going on. We have telescopes that help us see parts of the spectrum. The Hubble Space Telescope looks at visible light, some infrared light, and that is the visible light that our eyes can see. The Compton Gamma Ray Observatory helps us look at gamma rays, which are very energetic particles, whereas visible light is not as energetic. Somewhere in between are x-rays, which are also very energetic. It's important to see the whole spectrum of energies if you want to see what the universe really looks like. If I were trying to look out the window and describe spring with its green fields, what would I say if I couldn't see the color green? Green is one color, or one part of the color spectrum. If I was looking out the window and couldn't see the color green, spring would look pretty different and I'd be missing a whole chunk of information. What we're doing with the Chandra X-ray Observatory is we are putting an observatory into orbit that will be able to look at the x-ray spectrum and tell us about that part of the universe. What's neat about that is that x-rays are given off during a lot of different events, like when stars are exploding, galaxies are colliding, and black holes are sucking things in. This is really going tell us a lot about what is going on out in the universe that we haven't been able to see before.
Tell us a little bit about how Chandra is designed to gather and record x-ray information and get that data back to the researchers on the ground.
The Chandra is going to be in a huge orbit about a third of the way to the moon. It's in a special elliptical orbit that has to be outside of the Earth's atmosphere because the Earth's atmosphere absorbs x-rays. If we could see x-rays without having to send Chandra out so far, that would mean x-rays would be reaching us here on Earth, and we would have many more diseases, like cancer, because x-rays are very disruptive. We need to send our telescopes outside the atmosphere so they have a clear view. It's like looking through fog here on Earth, and we need to be outside the atmosphere. In this giant orbit, Chandra will actually be able to track a single object for forty-eight hours, but the Earth is in the way for the last twelve. It has a really long shutter speed, so it can look at things for a long time. The other interesting part of Chandra is the mirrors. The reason x-rays are so energetic is because they're so small. They're actually tinier than the distance between the molecules that make up the mirrors, so if I tried to bounce x-rays off of a mirror, they'd just go right through it. I wouldn't be able to bounce the x-rays into the camera that's going to then send the information back to Earth. What I have to do instead is bounce them very grazingly off the surface of the mirror, like a bullet would ricochet off of a wall if it hit at just the right angle. If you look at the Chandra X-ray Observatory, you'll see a very long, cylindrical structure which has about two thousand pounds of very smooth glass. The glass is coated with iridium to help the x-rays bounce off and end up at the cameras, which will then send the information electronically down to the scientists on Earth.
The other x-ray observatories that have been placed in orbit to do this kind of work were launched on expendable launch vehicles. Why does this telescope need to go up on a shuttle?
It needs to go up on a shuttle so we can make sure it gets there. Chandra has computers that don't have enough memory in them to load down here on the ground, so what we have to do is power the Chandra up in orbit and then load its computers. We want to make sure that everything happens successfully, and if it doesn't, we will still have the capability to bring the Chandra home. That's one of the advantages of flying on [a] space shuttle. You get people like me who are going to check out Chandra's systems, and the Inertial Upper Stage's systems, and make sure that everything is exactly right before we deploy it out into space.
The deployment is scheduled to occur before you go to sleep the first night of the mission. As a matter of fact, you're the one that gets to push the button. Could you talk us through the events that will be taking place for you and your crewmates after you reach orbit. Tell me what you will be doing as the five of you proceed to check out the telescope and send it on its way.
Day one is going to be extremely busy for all of us. Deploying Chandra is the most important part of the mission, so we want to be at our best. Unfortunately, your first day up in space isn't always the day you feel your best, but we're going to do everything we can to make sure that we do. I'm going to get a good night's sleep the night before, whether I like it or not, so that I am ready to go on day one. The first thing we will do on the shuttle when we get up to orbit is unpack. We were a rocket and now we're going to be an orbiting laboratory that's going to deploy Chandra. We just have to turn on the bathroom, turn on the galley, unpack the books that give the procedures on checking out Chandra, make sure that I have all my timers, and things like that. About an hour and a half after unpacking, we are going to start checking out the spacecraft systems. That should probably be complete within about the first four hours. We'll probably take a little break for lunch, as long as there's nothing else to work on. There are a number of things we need to do to the telescope that can only be done right before we deploy it. We will begin working on these things at about seven hours. It's important that we do every one of them in the right order, exactly right. I've been practicing those things quite a bit here on Earth. The Inertial Upper Stage and the Chandra are laying in the shuttle and the first thing I'm going to do is command it to tilt up to an angle of about 29°. Then I'm going to finish the spacecraft checkout. After that, at about seven hours, I'm going to tilt it up to an angle of about 60°. At the right moment, when Chandra's in the right place around the Earth to be able to get into the correct orbit, I'm going to make sure that everybody's ready, and I'm going to pull a switch that says "deploy". Eileen has to be ready to back away from the spacecraft after I deploy it. I also want to make sure that the Chandra folks up in Cambridge are happy, and that the folks in Sunnyvale who control the Inertial Upper Stage can guarantee that their Inertial Upper Stage is ready to do its job. Once I pull the "deploy" lever, Chandra and the IUS will just sail off above our nose. As we back away, we'll actually be looking right up the rear end of the rocket and we'll be able to check and make sure everything looks normal and make sure that it's moving correctly. About an hour after that, the Inertial Upper Stage will fire each of its rocket stages and bring Chandra into the orbit that it needs to be in. Chandra will then take over with its propulsion system and move itself into that large elliptical orbit.
It sounds like it could be a very complicated procedure. I'm sure you and your colleagues have come up with some scenarios when things don't follow the story that you just laid out for us. What are some of the critical failure scenarios that you have to look for, and how have you trained to respond to them should one of those things happen?
There are two sets of scenarios. One set of scenarios involves fixing things on board. In most cases, we have two sets of systems for everything if not more. A lot of redundancy involved in the Inertial Upper Stage and in Chandra. So we need to assess whether or not the other computer is capable of doing the mission on its own. We actually know that it is, but we'll make sure that everybody feels comfortable about it. Those are the kinds of things that we can fix on board. The people who control the IUS in Sunnyvale, California can also fix those things. That's a nice bunch of Air Force folks out there and I'm proud to be working with them. They can actually talk to the Inertial Upper Stage from different ground sites around the Earth. They can do their own assessment and they can send their own commands, certainly a large number of commands that I can't send from on board. We work together to fix those kinds of problems. Then there are the problems that involve going out and doing a spacewalk. Let's say that during the operation to tilt up the telescope, the lever arm that is supposed to push it up doesn't work. We have an alternate lever arm on the other side, so I'd disengage the primary, engage the alternate, and try and tilt it up again. That should work. In the unlikely chance that it doesn't work, Michel Tognini and I have trained to do a spacewalk. We trained with the same hardware that we'll be using out there, and we can go out and install a third lever arm and will actually crank the 50,000 pounds of the stack up manually. Then we will deploy it. We've got a number of different plans for the things that can go wrong. I think the challenge is to keep all the teams working together and keeping their minds open as to what the possibilities are of fixing the problem and how it can be done together.
I suppose you all have to be very careful since this has to go right the first time. This satellite can't be retrieved once it's deployed, right?
I've thought about that every single night ever since I've been assigned to the mission. This is a very special mission to be associated with. The telescope has been almost twenty years in the making, and there are people who have waited their entire professional lives to see what they're going to be able to see with this telescope. This is a once in a lifetime opportunity for the shuttle program to bring up this wonderful telescope, deploy it, and do it right. We have been training very hard to make sure that we are the folks that send it on its way in a good fashion.
Chandra is the third telescope of four that are envisioned in NASA's Great Observatories Program. What can Chandra "see" in the x-ray portion of the spectrum that complements the observation and the research that's done by the Hubble Space Telescope and the Compton Gamma Ray Observatory? How does all of that help scientists understand the "forces that are shaping our universe?"
Ever since we've had the Hubble and the Compton up in space, I think that a lot of eyes have been opened. Not just scientists', but the public's also. Look at the number of publications that are available that show you photographs of galaxies and of the edge of the universe. It's very exciting, but we want to see what [we] can't see. Hubble and Compton show us visible light, UV, and gamma rays. Visible light varies and gives off sort of long, lazy wavelengths. Gamma rays are very energetic. Somewhere in the middle are x-rays. These are given off in some very exciting processes that are going on out in the universe that we haven't been able to see. We think about things like black holes and the horizon to a black hole. There's a certain point when you get really close to a black hole where you can't see anything because everything's gone inside. With the Chandra, and the increased resolution of the Chandra, they're going to be able to see what the boundaries are and where those things are happening. This is a different kind of energy than Hubble and Compton have given us, and it's really just completing the story. Chandra is the third in the family of the Great Observatories and I think of it as the sister of the Hubble and the Compton.
You're carrying another telescope on board Columbia on this mission, one that won't be leaving the orbiter, that will be used throughout most of the days that you're flying. It's called the Southwest Ultraviolet Imaging System, or SWUIS for short. What kinds of observations will this telescope make during your mission?
Dr. Steve Hawley is in charge of that experiment and he could probably tell you very specifically exactly the kinds of targets we will be observing. As far as I know, SWUIS is going to look at ultraviolet energy from the moon, from Jupiter, from Mercury, any of the planets that we can see while we're up there. We're going to look at their ultraviolet spectrums. This telescope will be looking at ultraviolet light. It's a twelve-inch telescope that's going to look out of the orbiter hatch. We're actually going to have to point the orbiter in the right direction to be able to see these things. Dr. Steve Hawley is an astronomer and knows what he's looking for. So do the people on the ground, although Steve's view will probably be a little better than their view. It is going to be really interesting because Steve may find things that are unexpected. That's why we bring people to space. We go up there to look at things that we expect to see, but what's really interesting is when we find things that we don't expect to see and we get to take a closer look.
We've referred a couple of times to the fact that this mission is planned to last for five days. Your first trip to space lasted to over sixteen days and was devoted entirely to the study of microgravity science, and some of that will be done on this mission as well. From your experience, why is it important for us to be doing research on how things behave in an environment where there's microgravity?
It's not only important to study materials in an environment without gravity, but it's exciting. Think about a glass of water. If you look at it really closely, you see that that water is not actually flat in the glass. It's kind of creeping up the sides just a tiny bit. That's because these water molecules are conflicted. They like to stay with each other, but they'd also like to climb up the side of that glass. There's actually a battle going on. In an environment where gravity doesn't really influence the outcome of that battle, we are going to see what the water molecules will do when nothing else is pushing them around. It's a sort of a silly example, but it's very appropriate in that gravity is a very large physical force compared to a force like surface tension. Surface tension is the tension on the outside of a water molecule. It's what is influenced when [you] look at the little balls of water beaded up on your clean car. Surface tension is keeping that water molecule all beaded up because it looks out and it sees wax, oil, water, oil, water, which just doesn't mix. The water molecules would rather be with their water buddies, right? When you've got a dirty car, dirt, a kind of salty sort of thing, water, salt, sounds OK, and so that water drop wants to spread out. Gravity is really influencing those kinds of processes and it's hard to know what the molecules really want to do.
You studied these processes for sixteen days once before. Is five days long enough to learn anything new and important?
Five days is long enough to learn new things. You can learn new things eating breakfast in space. Even eating is a science experiment up there. I have to admit that with a five-day mission, I am hoping for a little bad weather just to extend the time, maybe a day or two. I think we'll still learn some very interesting things though. We've got a few different materials science types of experiments. Some of them involve plant growth. We are doing one really neat experiment with plants that have been genetically engineered to talk to us, to tell us how they feel. They're not going to get up and ask for a glass of water, but when we get home and the scientists analyze them, they're going to be able to tell if the plants are stressed or not. Did they like growing in microgravity? Stresses are things like: I don't have enough oxygen, I don't have enough water, and I don't have enough light. We're going to see, given different conditions in microgravity, whether or not they feel stressed. My job with that experiment is to actually take them every other day and analyze them. I'm going to take them out of the "Jell-O" that they're growing in and scrape it off. Hopefully, I will not stress them in the process. This experiment will tell us a lot about growing plants in space, which will help in future missions. Having enough to eat is not only important to the astronauts, but it's also important for things here on the ground because we're trying to understand how plants grow. When do they decide to grow up? How does a plant that started growing in microgravity decide which way is up? The scientists that we're working with have chosen a number of experiments and have taken away a bunch of the variables so that the only variable left is gravity. We're going to try to find out how these plants know which way is up.
There's another experiment on this flight called GOSAMR that involves advanced ceramic materials in microgravity. Give us a primer on the goals of this experiment and what's going to occur on orbit.
GOSAMR is a ceramic experiment,
but when you say ceramics, it makes me think of my coffee cup. These
materials are actually very different. They are called aerogels, and
they have a bunch of different nicknames, like "liquid smoke."
What they are is like "Jell-O." "Jell-O" is going
to be a bunch of different little pockets of water that are covered
in a thin skin. If you could really get inside "Jell-O" and
look, you'd see all of these little pockets. We have found a way to
take out the liquid and leave only the skin, and that is what aerogel
is. It is amazing stuff. It's an excellent insulator for heat, sound,
and electricity. With aerogel as an insulator, the R factor would be
20. They have a quarter-inch sheet of aerogel in the Mars rover, and
when it is -80° at night outside, it is 70° inside of the Mars
rover. This quarter-inch of insulation is giving you 150° delta
and it's very light. If you took a pound of aerogel, it would be the
size of a large refrigerator. It's a very interesting material, but
it's not clear. We'd love to make windows or insulators out of it, but
we'd also like to be able to see through them. The problem is that we
have really big holes and really small holes in the "Jell-O".
If we had only small or only big, then we would be able to see through
it. Because of the range of sizes, light is scattering. On this mission,
we are particularly trying to get very even pore sizes in the "Jell-O".
By doing this experiment in microgravity, we're going to have very even
pore sizes in our "Jell-O", and hopefully we will be able
to find a way to make aerogels here on Earth.
I feel very privileged to be assigned to STS-93 because we have two very important and significant things that are happening on our mission. One is the Chandra X-ray Observatory. I am part of the team that's going to deliver Chandra to orbit and I am very excited about that. I think about how much our understanding of the universe has been increased because of the Hubble, and I realize that I am part of an observatory that is going to do that for x-rays. I've been reading a book called Exploring the X-ray Universe, and I realize that before I finish this book, they're going to be ready to rewrite it because of what this telescope is going to do. That's one very important part of our mission. The other important aspect of our mission is Eileen Collins as our Commander. I'm very proud to be serving with Eileen. She's a great Commander and is really nice to work with. What's really important about this is that Eileen's presence on this mission is going to show a bunch of young girls that, if she can be a shuttle Commander, they can too. In fact, they can have any job that they want. We need our kids to start setting those kinds of goals. So I think that Eileen's presence as the first female shuttle Commander is going to have far-reaching effects. We may not even know some of them. I'm excited to see what they turn out to be.