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Sunita Williams' Frequently Asked Questions:
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How do you get and store the oxygen you need? How much oxygen do you need for a spacewalk?
We have oxygen shipped up to us in the Space Shuttle and also in a Russian spacecraft called a Progress. We have tanks which we store oxygen on the Station once it is transferred from these spacecraft.
We also make oxygen from water using a machine called Elektron. It uses a concept called electrolysis to break down water from H2O to hydrogen and oxygen.

What is Neemo 2? How does it work?
NEEMO actually stands for NASA Extreme Environment Mission Operations. It is one of the programs NASA uses to get us astronauts ready to live in a closed environment like a spacecraft. We live in a module underwater, about 50 feet for about 10 days at a time. When you "live" underwater at this depth, we call it "saturation diving," which means that your blood becomes saturated with as much nitrogen as it can take. This will take a long time (approximately 17 hours from 50 feet) to ascend to the surface to avoid getting the bends - or a big bubble of nitrogen stuck in your bloodstream. So, this habitat sort of imitates living in space in a spacecraft because you can't just get back to the surface of the Earth easily and you are isolated with only a couple of people. You are living in an extreme environment, just like space.

What do you eat in space? How do you cook your food in space? What does it taste like?
Our food is half Russian and half American. Some of it is dehydrated and some of it is ready to eat. All we really do it hydrate food and heat it up.
On the American side we have everything from macaroni and cheese to beef enchiladas, and crawfish etouffee. All of this type of food is in a package and just needs to be heated up in the oven. There is a lot of variety even in the desserts which include things like candy, pudding, fruit cocktail and cookies.
On the Russian side we have beef, lamb, chicken and rice or potatoes in a can usually. The cans just need to be heated and then we eat right out of them.
The food is generally bland so we have bottles of sauces to spice it up, like hot sauce, soy sauce, horseradish, garlic and pesto.

When you work outside the Space Station would you float away if you let go? Are you ever afraid when you are on a space walk?
Yes, and no. We have a safety tether that is a line of wire that holds us to the structure of the ISS. We also have cloth tethers and a rigid tether which we use when we need to let go and use both hands for some work we are performing. If the wire tether broke for some reason and we weren't holding on we could float away pretty easily. In that case we have a SAFER (Simplified Aid for EVA Rescue), which is like a little jet pack on our backs that we can use to fly ourselves back to the ISS. Although we are trained to use it, we try very hard not to get into a situation where we would have to.

What can you see in space from the Space Station? Asteroids? Garbage? Exploding stars?
Well, we aren't that much closer to those things than you are. We are only about 200-250 miles above the Earth. So, we just see things a little clearer than you do on Earth because we have no atmosphere up here to blur the view. We can see the darkness of space pretty clearly and the thin layer of our atmosphere that protects our planet from space.

Do you have to change the clocks in your computers to match up with those on Earth, because time goes slower for you when you are going so fast?
Great question! We work off of Greenwich Mean Time. But there is a difference in our time versus the ground time. That is because we get our time from GPS. Since these are satellites, their time does drift, so there is actually about 14 seconds difference between the time onboard and that on the ground. That difference has grown throughout the 7 years life of this Station, so it isn't too much. Unfortunately, I don't think I am getting any younger up here even though we are traveling at approximately 17,500 mph.

What would fire look like in microgravity?
I don't know personally, but I do know we have done some experiments on fire. I would think it would be different from the way a flame burns on the ground, but I am not sure. We'll have to get the experts to find out. Right now we don't have any experiments up here that involve fire.

What do you do to get exercise when there is so little gravity?
We have 3 types of exercise equipment up here. A treadmill, a bicycle, and a weight lifting machine. They all have a way to hold us down on the machine. The treadmill uses bungees and a harness. We are clipped in the bicycle using the pedals you see on racing bikes. The weights are actually rubber cords that we pull to stretch through a machine connected to a harness we wear. The equipment and exercises are necessary so that we can stimulate our muscles and bones particularly in our legs. We don't do any walking up here so our legs don't get much exercise. If we didn't do anything, our bones and muscles would deteriorate because we don't need them here. The body realizes this and starts to adapt by not using energy to build muscle and bone in these areas. This is fine for living in microgravity, but will be bad for when we come back to Earth or when you future explorers land on the moon and Mars. You will need to be able to walk around!

How are your circulatory, digestive, and excretory systems affected when you don't have much gravity?
Just like the muscles and bones, the body starts to adapt! Fluid shifts since gravity is not keeping it down. For example, most astronauts look like their heads have swelled up a bit once on orbit. That is the fluid shift keeping more fluid in your upper body since it doesn't have gravity pulling it down. Likewise, our hearts may not be working as hard because they don't have to pull the blood up from the lower extremities of our legs.
For the digestive system, it takes a while to feel hungry. The food is floating around in the stomach so you don't get that feeling of an empty stomach until your stomach muscles adapt to push the food down into the intestines. This takes a while - maybe a week or so. Likewise, it takes a while for your intestines to learn to really push the food through since nothing is pushing the food down and through. But those muscles adapt too and your body knows when it is time to get rid of the excess.
These are really great questions because it is hard to understand just how adapted we are to gravity and how everything our body does is based on living in a gravity environment. What is really amazing is how well the human body can figure out what it needs to do to adapt and it does. The human body is an incredible machine, so take care of yours.