The following questions were answered by astronomer Dr. Cathy Imhoff of the Space Telescope Science Institute.


What are the requirements to become an astronaut?

All astronauts have some special skills, either as pilots or scientists. So they have all gone through college and gotten some experience in their particular field. I don't know of any age requirement, but the experience that is needed would probably mean that the astronauts are at least 25, more likely over 30.


When astronauts go up into outer space, what do they wear under their spacesuits?

I understand that it's pretty cold in space, so I bet they wear long underwear! I asked your question about what an astronaut wears to my friend, Ron. He said: Under the orange launch and entry suits we wear a pair of long johns. Since you are likely to be in the suit for several hours and since you can't open it up in any way to "go," we also wear a diaper for adults! As soon as we reach orbit we remove the suits and put on regular clothes for the duration of the mission (no diapers!). The suits are put back on just before deorbit. The EVA suits are the same with an added cooling garment that goes on over the long johns. It is like another pair of long johns with small plastic tubing woven all through it. Chilled water is circulated through it to get rid of body heat and solar heat.


How near can an astronaut in a spaceship get to the sun before he or she gets burned?

It depends on how well the spaceship is designed to handle the heat and light. Even an astronaut in space around Earth could get burned if he or she didn't have a good spacesuit on — one side would get fried by the sun, and the other would freeze in the dark! Now you know why the astronauts have to wear such bulky spacesuits!


How does the pressure in space affect you?

Well, there isn't any pressure, because space is nearly a vacuum. That is one of the reasons that astronauts wear spacesuits.


How can astronauts breathe in the space shuttle?

In order to breathe on the shuttle, they take along a supply of oxygen. There are also filters that take carbon dioxide out of the air. Did you see the movie Apollo 13? One of the biggest dangers for them was that their oxygen tank exploded, and their carbon dioxide filters were clogging up!


How and what do astronauts eat in space?

My friend Ron was an astronaut who rode on two shuttle missions. He told me that they eat whatever doesn't have to be refrigerated. So at first they eat up the fresh fruit and vegetables, so they don't spoil. Then they eat the packaged meals that you heat up. They have to use a sort of toaster oven though, they can't use a microwave on the shuttle. I think by the end of their trip the food gets pretty boring!


What happens if the astronauts lose one of their tools?

Astronauts try not to lose anything, including tools, because they float off into orbit. Later you might be going along in orbit and that tool could smash into the shuttle! Fortunately something like that would not stay in orbit forever. The shuttle is only a few hundred miles up. There is a very small amount of atmosphere up there, just enough to gradually slow "space junk" down so that it eventually falls into the atmosphere and burns up.


Why do the astronauts on the space shuttle sleep in those cabinets? Why don't they sleep in the seats that they take off in?

The astronauts sleep in a particular spot so that they don't drift around in the shuttle while they sleep. If I remember correctly, they sleep in something more like a sleeping bag (although I could be wrong). Also, the astronauts say that they feel more comfortable with the feeling of something around them rather than floating free. The sleeping area is away from the command cabin so that the noise and activity doesn't bother them. Usually there are two teams of astronauts, each working 12-hour shifts. One team works while the other eats, sleeps, and exercises.


Does weightlessness in space have a long-term effect on the human body?

I understand that one problem is that the bones lose some calcium. Exercise helps, but it doesn't stop this completely. This is a major area of study for manned spaceflight. The Russian cosmonauts have a lot of experience in long missions on their space station Mir. NASA is also gaining experience with this. It's a problem we will need to solve before we send people to Mars. It's a LOOOONG trip!


Why can't a person go into a spaceship with everything he needs and see all of the planets?

To go to Mars would take at least a year. You would need to take in your spaceship all the air, food, and toilet paper for a year. Right now you would need such a big, heavy spaceship that you couldn't launch it! So people are finding ways to reduce the weight for instance you can use plants to help generate the oxygen you need to breathe. Also we worry about what will happen to people who spend so long in weightlessness. Their bones may become so soft that they won't be able to stand up on Mars to walk around and explore!


When you're out of a spaceship, how do you prevent being sucked into space?

Well, if you are out of the spaceship, you ARE in space. I hope you have your spacesuit on!


If all the engines on a space shuttle broke down, and if they couldn't be fixed, would the space shuttle just continue to orbit Earth? What would happen? Could it land?

Well, if ALL the engines broke down on the shuttle they would be in a BAD way. Have you heard of Isaac Newton? He was an English scientist who described many important scientific "laws," including his laws of motion. One of them is that an object in motion will continue in that motion unless an outside force affects it. So, applying that to the shuttle, unless something can slow the shuttle down, it will stay in orbit.

As it turns out, the shuttle is low enough that there is some thin atmosphere that would eventually slow it down. So eventually — maybe it would take years — the shuttle would come down. But that wouldn't help any unfortunate astronauts! I think we would try to rescue them first! As I understand it, the shuttle pretty much glides to Earth when it lands. I don't think it uses its engines except to push it out of orbit. So if they could get the shuttle out of orbit and head to Earth, I think they could land it.


When the astronauts walked on the moon, what kind of samples did they bring back? Where are the samples now? Is there still research going on with the samples and will there be astronauts walking on the moon or other planets in the near future?

I think the astronauts picked up most anything that looked interesting! If I remember correctly, at least one of the astronauts was a geologist, and all of them received some training in geology so they would know what to look for. The rocks were collected almost 25 years ago and have been thoroughly studied. I believe that they are mostly just in storage now. However, I have heard of a program where NASA will work with certain schools who receive some samples of lunar rocks to experiment with. Right now our astronauts are only traveling in the Shuttle. Although many of us would like to have men and women visit the moon and Mars, there are no current plans. This is in part because we no longer have manned spaceships that can travel that far.


What is it like in space?
Empty, dark, hot on one side (where the sun shines), and cold on the other (in shadow)!


Is there any kind of magnetic force in space? Would magnets stick together or would they come apart?
Magnetism is one of the basic forces of nature. It exists regardless of whether there is gravity or air. Magnets would definitely work. What would be neat would be to see them floating weightless in space. You could push and pull the magnets around using other magnets.


The following questions were answered by Ron Parise, a mission specialist who has flown on space shuttle missions:


How long does it take to actually get into space after the launch?
It takes 8.5 minutes to reach space after launch.


What shape must you be in, physically and mentally?
To be an astronaut you must be in good physical shape (but not an athlete!) and ready to work with the rest of the crew without getting mad at anyone in close quarters over the length of the flight.


What kind of training must an astronaut go through?
An astronaut must undergo extensive practice on the experiments that will be operated during the mission; training on living in space like eating, sleeping, going to the bathroom, housekeeping; and emergency procedure practice in case you have to get out in a hurry under many circumstances both on the pad and in flight.


What does it feel like to be floating?
Wild!!! It is like going down a hill on a roller coaster! Maybe a combination between that and being in a swimming pool without the viscosity of the water