Canadian astronaut Chris Hadfield is now on his third voyage to space. This time, he travelled by Soyuz rocket, but in the past, he travelled on the space shuttle. He's even been on the Russian space station Mir, before its orbit was lowered to let it disintegrate in the Earth's atmosphere over the Pacific Ocean. In his most recent mission, he's staying on board the International Space Station as its new commander, so he's got an eagle's-eye view over the experiments that are being performed in outer space.
Experiments in outer space
The core purpose of the International Space Station is to be a platform for experiments that can't be done on Earth. At the time when Chris Hadfield was interviewed after his major promotion, the ISS was home to 110 experiments.
A lot of those experiments are about how the absence of Earth's gravity affects things, but some of them look at hard vacuum, extreme cold or cosmic radiation, instead. All of those conditions can be simulated on Earth for short periods of time, but on the ISS, you can find those conditions all the time. You can even get ultra-specific and set up an experiment which needs extended and complete absence of sunlight as well as absence of gravity. You can't do that on Earth, but you'll always be able to find or make a place in the ISS where those kinds of conditions are ongoing.
Other kinds of experiments have to be done outside the Earth's atmosphere to get any kind of real results. A lot of those experiments have to do with cosmology and the nature of the universe. One of those experiments was all about trying to understand dark matter a little better. The first part of that one was just completed on Chris Hadfield's watch. It's posts like that, and all the photographs, that make it so interesting to follow Chris Hadfield on Twitter!
Obviously, to keep the ISS afloat as an experimental platform, there're also a lot of maintenance and upgrades that have to be done. There's also regular traffic turnover as supplies come in and new crews take over from old crews.
Why are experiments in outer space important?
Some of the biggest experiments currently going on in the ISS are about how the absence of gravity affects human health. That's going to be very important if space exploration's ever going to get beyond Earth and the moon.
It's already known that when there's no gravity, the body isn't going to work the way it always does. Obviously your sense of balance is going to be totally wrecked. Gravity can't help your food get from your mouth to your stomach and onward to your intestines. Your heart doesn't pump against gravity to get blood to your head. You don't even have to use any muscles to hold your head up!
You can't figure out what's going on while you're still on Earth. When no-gravity situations are simulated on Earth, you get a few minutes without gravity, tops, and that's only if you're going on the Vomit Comet. But a few minutes doesn't exactly cut it when you're wondering what happens to the human body when it's in freefall for months on end.
That's what experiments like the Cardiovascular Health Consequences of Long-Duration Space Flight experiment are for. "Vascular" is actually a whole bunch of ongoing experiments, all grouped together under one name. Chris Hadfield and the other astronauts get to be guinea pigs.
Most people already know that freefall strips bone and muscle mass. Exercise is one way to cut back on those losses, but there's still a lot of research needed in this field before someone's going to be able to crawl out of a rocket capsule on Mars under his own power after a year or so of freefall.
It gets even worse. The heart doesn't have to work as hard, so it shrinks. If you're even the least bit at risk for a heart attack or stroke, ongoing freefall's going to make that risk a lot higher. Scientists have found that freefall actually accelerates aging! So much for all those science fiction dreams about using space stations to extend lifespan and health among seniors.
On the other hand, if scientists can figure out what's going on that makes these kinds of things happen, there's a good chance they can find a way to get around it. That's the other part of what makes experiments in outer space so important. First, you've got to understand what's happening. Then you're trying to understand what makes it happen. Finally, if it's something negative, you can try to find a way for it not to happen.
A lot of these findings can be used back down on Earth, even for people who aren't ever going to leave Earth. If you can find a way to reduce the risk of heart attack or stroke, that's got applications right here at home. That's how all those health experiments in outer space can help out everyone in the long run.