Ask the Crew: STS-113

From: Evan, Omaha, Neb., Age: 12
To: Mission Specialist Michael Lopez-Alegria

Question: When you guys go on a spacewalk, how do you get enough oxygen for that long period of time? My uncle was thinking it's nearly impossible to get enough oxygen for about six hours. He thought it might be really compressed or the suit recycled the carbon dioxide from the astronauts. Is either of these right, or is it something else?

Lopez-Alegria: Well, Evan, actually the first guess is correct. We use oxygen that is compressed into two small tanks at a pressure of about 900 psi when we start the spacewalk. So we have enough oxygen probably for about eight hours, depending on how fast we are using it. But that's a good question.

From: Sean Coate, Ft. Myers, Fla., Age: 28
To: Pilot Paul Lockhart

Question: Does it seem familiar to be flying the same shuttle and bring home the same three people you left at the station just a few months ago?

Lockhart: The answer is a resounding yes. It seems very familiar. In fact, that made me very comfortable and allowed me to learn the mission and be able to contribute to STS-113 very quickly.

From: Year 4B Sacred Heart School, Canberra, Australia, Age: 9 and 10
To: Pilot Paul Lockhart

Question: How do you transport water to the space station?

Lockhart: First, I'd like to say we just passed over Australia and looked down on you there at 4B Sacred Heart School. As for transporting water to the space station, we use water that we make here on the space shuttle. We use fuel cells that use liquid oxygen and hydrogen to make electricity, and one of the byproducts is water. When we're docked to the station, we use special bags to collect some of this water from the space shuttle and take it over to the space station, where they use if for various things.

From: Dennis, Ocala., Fla., Age: 49
To: Pilot Paul Lockhart

Question: When you go to sleep, what time zone do you use? How do you know what time it is?

Lockhart: We use a mission elapsed time clock on the space shuttle that starts as soon as we lift off, and all of the tasks and all of the procedures that we do are referenced against this mission elapsed time. So we go to sleep at a certain mission elapsed time and wake up and also do the rest of our activities.

The space station uses Greenwich Mean Time. So when we're docked to the space station, we always have to make that conversion between mission elapsed time and Greenwich Mean Time in order to make our activities between the two vehicles in order.

From: Paul, Gadsden, Ala., Age: 36
To: Pilot Paul Lockhart

Question: When the space shuttle goes sub-sonic, the double sonic booms can be heard and felt on the ground near the landing area. I was in Florida for a landing earlier this year and got to hear the sonic booms made by the shuttle. What I have always wondered about is this: Can the astronauts inside the shuttle hear and or feel the sonic booms? If you can, what is it like inside the shuttle?

Lockhart: When we're inside our suits -- our launch and entry suits -- for landing, we cannot hear the sonic booms that occur. However, as we start to decelerate from hypersonic speeds, you can feel -- at least in the orbiter Endeavour -- you can feel the vehicle shake and shudder a little bit. But you do not hear the sonic booms. So what you feel then are the vibrations as the air passes over the wings of the orbiter as we slow down from hypersonic speeds.

From: Mary Wagner, Pittsburgh, Pa., Age: 48
To: Mission Specialist John Herrington

Question: Our home-school co-ops' signatures are flying with STS-113, and we are very honored to be one of the many chosen schools for this year's Signatures in Space. When we watch a spacewalk, it looks as if things are in slow motion. Does it feel like that when you are working during the spacewalk?

Herrington: Actually, in the pool [when] you train, the water actually damps out your motions. In space, since there's nothing to damp out the motions, if you get going you have to apply force in the opposite direction to stop yourself. So you do have to be very careful, so you do try and move as slowly as possible so you can maintain control.

From: Holmes Macmillan, Toronto, Ontario, Canada, Age: 39
To: Mission Specialist John Herrington

Question: What do you do when you spill some water or other liquid inside the station or shuttle? Couldn't this pose a very serious problem?

Herrington: I guess it depends on the size of the spill. We're very careful with liquids, water and juices that we have. If they do get away from us, we do make a point of cleaning them up but you're very careful that the water you're drinking doesn't escape and cause a problem electronically.

From: Jonathan, Atlanta, Ga., Age: 15
To: Mission Specialist John Herrington

Question: What is it like to be placed on your back for the three to four hours prior to launch? Do you get stiff at all, not being able to move around?

Herrington: That's a good question, Jonathan. We have little lumbar cushions that we can actually inflate in the lower portion of our backs. So if your back starts to hurt, you can actually inflate the cushion and it will relieve some of the pressure and move your back a little bit. We try and move around and stretch a little bit, and sometimes it gets so quiet and not much is going on, that you can actually doze off for a little.

But on the station flights we're having right now, we have a very small window in which to launch that things progress very quickly, so you won't be on your back for very long.

From: Frank Mattocks, Bordeaux, France, Age: 53
To: Mission Specialist John Herrington

Question: Briefly, how do you know where you are in space? Do you use geographical coordinates and height or some other system?

Herrington: Actually, we use latitude and longitude. We have a program on one of the laptops called "World Map," and at any given time, we can look over and see where we're at. We're presently flying at, I think, about 212 nautical miles above the Earth and roughly over the North Pacific, probably northwest of Hawaii right now.

From: Patty Branch, Clear Lake City, Texas
To: Mission Specialist John Herrington

Question: Will you have a Thanksgiving feast on the space station? Any special activities planned? Do you get the football scores?

Herrington: Three great questions. 'Did we have a Thanksgiving Feast?' Let's see … I had ravioli and cornbread stuffing. We put a bunch of food in the oven. We had the folks from the International Space Station come over to the space shuttle. We had smoked turkey and a variety of other foods -- candied yams, I believe. It was really, really good. 'Any special activities planned?' We had a spacewalk that day. I believe it was the first spacewalk on a Thanksgiving. I think Tom Jones and Tammy Jernigan on their flight tried to have a spacewalk on Thanksgiving but weren't able to due to a hatch problem. 'Do you get the football scores?' Stand by and let me find out … Yes, we get the football scores.