A while back, I was accepted to a NASA Social at the Johnson Space Center in Houston. It was, no exaggeration, one of the best days ever. NASA Socials are public events hosted by NASA for users of social media, where regular people are given tours, lectures, and access to areas where they wouldn’t generally be allowed. For NASA, it’s free social media publicity (check out #NASASocial on Twitter to see how people live-tweet these events), and for us it’s a peek inside. It was my first time visiting NASA, where I hope to someday work, so it was a huge deal, and an even huger success.
Not only did I have a fantastic time and meet lots of interesting people, I learned an awful lot about life on the International Space Station (ISS). The event was based around astronaut health and fitness, so this post will be about that (although there was a whole lot more to the actual event). As I wrote before, the main problem with astronaut health in space is the lack of gravity causing a loss of muscle mass and bone density. As one of the physiologists at Johnson explained, your bones are a product of your environment: “If you carry a backpack with weights in it around for a long time, your skeleton will grow and adapt,” and in space, it’s just the opposite. Since your bones are supporting less weight, they adapt, with unfortunate consequences when you get home.
One of the ways scientists combat this is through astronauts’ diets. One of the causes of the loss of bone density in space is the limited diet: astronauts can only eat foods that can be kept for a long time, which limits the sorts of stuff that they can eat. What we eat affects our bodies’ pH balance, which ought to be just about balanced between acidic and basic. The body regulates the pH balance by storing acids and bases to release when things get off-kilter. Bone happens to be one of the main ways in which the body stores base, so if the body is too acidic, bones will break down to neutralize it. In order to combat this breakdown of bone mass, astronauts have to eat a well-planned diet with a careful balance of potassium and different kinds of proteins to neutralize the body’s pH. Fortunately, well-planned doesn’t have to equal nasty – we got to try some astronaut desserts, and it is not astronaut ice-cream-gross-nostalgia-cookies anymore.
While diet is important, the research there is still very much changing, so we spent more time on the other way astronauts combat the effects of microgravity: working out for 2.5 hours every day. We have 3 workout machines in space: a stationary bicycle, a treadmill, and a weight-lifting machine:
The treadmill is called the COLBERT (yes, after Stephen) – since there is no gravity on the space station, astronauts have to use bungees and harness to strap themselves down to the treadmill, and they adjust the number of clips on the bungee to simulate body weight – the less clips there are, the harder their muscles have to work to keep them upright on the treadmill. So, the treadmill isn’t just for running like it is down here, but it’s also for simulating upright body weight so that those muscles still work when the astronauts get back home and need to stand on their own again.
The weight lifting machine is called the ARED, and the way it works is even more interesting. Again, since there’s no gravity, lifting free weights on the ISS wouldn’t be much exercise at all. So, instead, the ARED consists of two evacuated cylinders with plungers in them – the arm which astronauts lift is connected to those plungers. It’s like pulling a full garbage bag out of the can – since there is no air in the can under the bag, it’s difficult to pull the bag out unless some air gets by. With the evacuated cylinders, the same difficulty comes from trying to pull the plunger out of the evacuated cylinder – there’s no air in there, so it’s difficult to pull the plunger and thus lift the arm. The difficulty (and thus the “weight” being lifted) can be adjusted by changing the angle of the arm.
I don’t have a picture of the stationary bike, because it’s literally just a pair of pedals with a little dial for resistance: no handlebars, no seat, nothing at all like an actual bicycle. And, since any vibration is liable to shake the space station into an unwanted change in configuration, nothing is attached to the walls. There is some steadying, but for the most part, all three of these devices are free to float around, tip, yaw, spin, and generally be hard to get used to. With 2.5 hours a day, though, there’s plenty of time for astronauts to get there!