Space Travel Is Really Bad For You

It turns out space travel wrecks the human body. So much for our fanciful dreams of gallivanting through the galaxy, right? This realization was a lot like when our anatomy professor pointed out that things like dragons and gryphons are impossible because of the wing-to-body ratio required to fly as weight increases. He was all, "There's a reason there are no flying birds bigger than a dog" (and the awesome giant fliers have gone extinct).

But back to space travel.

I went to a veterinary conference for exotic animal vets (to learn about bird stuff), and the keynote speaker there was a vet for NASA. Yeah, that blew my little mind. Sci-fi and vet stuff generally hang out in different corners of my life, but for a whole hour, this guy talked about training for space missions, showed pictures of himself in space, and discussed the physiological effects of space travel on animals and people. And because he was talking to hundreds of geeky veterinarians, a lot of the questions that got asked were things like, "If we discovered aliens, would veterinarians or physicians be involved in medical issues? We're trained in multi-species thinking, after all."

So other than getting the inside scoop on some NASA stuff, and meeting a guy who'd been to space more than once, I also learned stuff. That is, after all, the point of conferences. And sadly, space isn't somewhere you want to be any time soon.

1. Bone and muscle loss.
Everyone knows the ISS astronauts have to work out constantly to keep up their muscle mass. However, not having gravity really impacts the body. Without that constant pull on the bones and muscles, the cells get mixed signals and start to wither away. The actual structure of the bones gets irreversibly altered (a decrease in the amount of cancellous bone, not unlike in osteoporosis), because the mechanical load on them is changed.

2. Fluid shifts and increased intracranial pressure.
Similarly, since body fluid isn't pulled down by gravity, it floats up to the upper body and head, altering normal fluid pressure. This can affect the retina and vision, sometimes permanently, and cause swelling of the head. Also, astronauts lose fluid volume too, so their hearts have less to pump and therefore begin to lose strength.

3. Balance.
The vestibular system (your inner ear) depends on visual input for balance. As you can imagine, in a weightless environment, that gets screwy. Apparently, new astronauts usually get very motion sick their first day or two on the ISS.

4. Sleep disruption.
Being weightless is essentially being in constant free-fall, and it's very hard for astronauts to fall asleep until they get used to it. You get startled awake--kind of like when your head drops and you snap awake--and there's a lack of REM sleep.

5. Radiation.
Without the Earth's magnetosphere to protect us, solar radiation is a big concern. This might be one of the biggest health considerations for a Mars colony. Radiation affects rapidly dividing cells first, so that means the bone marrow, which can lead to cancer, immune cell dysfunction, and blood disorders.

This is to say nothing of the psychological effects of prolonged confinement and isolation. The speaker also talked about the rigorous training astronauts undergo, and the frequent injuries sustained related to the space program but not necessarily space itself. The space suits are extremely heavy, and it's so common for astronauts to injure their shoulders from working the suit arms, pretty much everyone who goes to space can expect a shoulder injury. I believe the speaker said he'd had three shoulder surgeries, and he's about average.

So for now, I think I'll let other people brave the void while I appreciate them from down here.