Astronaut Stephanie D. Wilson completed her first space flight on Space Shuttle Discovery in July. Recently, she talked to USBE about the 13-day flight.

USBE: What was the goal of this mission?

Stephanie Wilson: STS-121 was the second return to flight test mission. After the Columbia accident, NASA put into place the Columbia Accident Investigation Board and as part of return to flight we had to implement recommendations from that board, and so STS-121 was the second flight for that. We tested techniques to inspect and repair the vehicle in orbit. One example was our first space walk, where we demonstrated the fifty-foot boom that we grappled to with our shuttle arm to inspect for any launch debris damage.

On our third space walk we tested repair material. We also validated changes made to the external tank. The first return-to-flight mission, STS-114, had foam loss; so for our flight that area was removed. We were able to demonstrate that changes made to the external flight were effective and was a stable design. We also delivered supplies to the International Space Station, or ISS, and we delivered a third crewmember, Thomas Reiter, a German astronaut and a member of the European Space Agency. 

USBE: What was it like working with the robotic arm in space?

SW: It’s almost like a video game. There are 2 hand controllers. One moves in translational  axis and the other in rotational axis; much like an airplane stick in a fighter aircraft. We are moving hand controllers and positioning the arm in attitude, and also in translation, to a point in space that is defined by the reference frame in which we fly.

USBE: The supplies you carried were really heavy, what was the total weight?

SW: We transferred about 5,000 pounds of cargo. The Multipurpose Logistics Module, when it was full, weighed about 30,000 pounds.

USBE: What sort of equipment did you have on board?

SW: We had food for the Space Station crew. We also had experiments and an -80◦ laboratory freezer. We had a new oxygen generation system that we were pre-positioning for a future flight. We had new exercise equipment: treadmill, and cycle ergo meter for the Space Station crew. Those were just a few of the items.

USBE: What did you eat on board?

SW: Each crewmember is able to choose their food pre flight. Unfortunately, I did not look at the list of food choices, but in general the Space Station has a mixture of American- and Russian-style food.

The American is much like military, its prepackaged MRE, or Meals Ready to Eat, with a variety of meats served with mashed potatoes, carrots, and green beans. It comes in a dehydrated fashion and we add the water once in orbit. There’s egg and sausage, chicken teriyaki, spaghetti, strawberry. The Russian food comes packaged in cans, so it’s more like tuna and diced vegetables.

The freezer will be used to store samples for experiments that are conducted aboard the Space Station. Since we were a return-to-flight test mission, we did not carry very many experiments. Our mission objectives were dedicated to repair techniques, vehicle inspection, and repair materials for the wing. We transferred the supplies so that the Space Station crew could conduct the experiments.

USBE: If you were doing experiments, what sort of experiments would you do?

SW: Every space station expedition has a different focus for their experiments. There is some that a medical related, perhaps looking at cancer cells and comparing those experiments with samples that might also be tested on the ground. What’s good about doing experiments in space is that there is the absence of gravity. In some ways, the chemistry operates in a different manner. We also conduct a protein crystal growth experiment and being grown without the absence of gravity, they grow much larger.

USBE: How would describe the sensation of being weightless?

SW: We were in space for 13 days, and the best way I can describe being weightless is if you can imagine when you are floating in a pool and being buoyant and suspended, or for those who have ridden on roller-coaster rides, imagine the ride is coming over the top and being lifted out of your seat.

USBE: What do feel like when you return to earth?

SW: You feel very heavy. You very much notice the existence of gravity, and it takes a little more effort to do some of the normal things like walking, bending, or getting out of a seat. After a few days, your mind remembers what it feels like to be in gravity.

USBE: You had an excellent view of Earth when you looked out of the Space Shuttle’s window, what is it like?

SW: It’s hard to do it justice. It’s an amazing and spectacular view. The colors are vivid: the blue of the oceans, and the reddish orange of deserts. And what is most apparent is that there are no borders. Here on earth, we are very much bound by ‘this is my territory, this is my land, or this belongs to me.’

In space, you don’t see borders and it becomes very apparent that we are in this world together and it really stresses the fact that we should be unified as much as we can because we all live together on this one planet. 

USBE:  How far up where you?

SW: We were about 200 miles of the surface of the earth. That’s where the Space Station orbits.

USBE:  Do you feel anything on reentry?

SW: No, the thermal protection system on the shuttle does an excellent job in rejecting the heat, in shielding us from the heat, which gets to be about 3,000 degrees as we are coming through the atmosphere. Inside, we are in our launch and entry suits and that can also be a barrier and serve as a pressure shield.

USBE: When I spoke to Dr. Darryl Pines at University of Maryland recently, he recalled a wish you had as an undergraduate at MIT to be an astronaut.

SW: When I was 13 I had an assignment at school and I interviewed an astronomy professor at Williams College. From there my interest developed more towards engineering, but I still had an interest in space and aerospace and in mind I always wanted to become an astronaut.

USBE: How did your make your dream come true?

SW: I first worked at the former Martin Marrietta Aeronautics on Titan IV [vehicle used for launching imaging and signals-intelligence satellites and Air Force missile warning satellites] and I was performing structural dynamics analysis. Then I went to graduate school and did a masters in aerospace engineering at the University of Texas. After that I went to work at Jet Propulsion Laboratory, or JPL, on the galley of spacecraft, which was the robotic spacecraft that went to Jupiter.

While I was at JPL I applied to the astronaut program, once I had met the minimum requirements, which is to have a bachelor’s degree in engineering, science, and math, and 3 years of related work experience. Along the way, I tried to choose jobs that would satisfy me professionally, and also lead to more opportunity. NASA invited me for an interview and I was fortunate and very blessed that I was accepted.

USBE: Have you talked to Dr. Mae Jemison since you came back?

SW: I have spoken with her. She has been very supportive while I have been training here in Houston. She has made herself available to answer any questions. She has been wonderful. I hope to see her in October. She and her foundation are participating in an event in Chicago on flying and physics.

USBE: I know when you meet young people, one of the first questions they ask is 'what is it like to be an astronaut?' What do you tell them?

SW: Well, I tell them that we do something different every day. As an astronaut, I could be flying a T38, which is an aircraft trainer. I could be scuba diving in our pool where we practice our space walk. I could be flying a robotic arm in simulation, or in meetings supporting another mission, or I could be working in mission control speaking to the current crew that is on orbit. It’s a widely varying job.

USBE: When do you go back to space?

SW: I’m not sure when that will happen. With the shuttle retiring in 2010, we have many astronauts who have not had their first flight. We’ll be bringing Moon and Mars Exploration Vehicles on line, hopefully, with test flights in 2012, and if I am asked to fly those missions I’ll be happy to go. But, they might be looking to have younger people; something I’ll quite understand.