Eye Problems From Space Affect At Least 21 NASA Astronauts

A reader sends this report from Universe Today: How does microgravity affect your health? One of the chief concerns of NASA astronauts these days is changes to eyesight. Some people come back from long-duration stays in space with what appears to be permanent changes, such as requiring glasses when previously they did not. And the numbers are interesting. A few months after NASA [said] 20% of astronauts may face this problem, a new study points out that 21 U.S. astronauts that have flown on the International Space Station for long flights (which tend to be five to six months) face visual problems. These include "hyperopic shift, scotoma and choroidal folds to cotton wool spots, optic nerve sheath distension, globe flattening and edema of the optic nerve," states the University of Houston, which is collaborating with NASA on a long-term study of astronauts while they're in orbit.

yeah, i'm not interesting in going to space

[shadowrat]

bone density plummets, muscles atrophy, eyes degenerate. Are we telling this to kids that go to space camp? Being an astronaut is as bad if not worse for your health as playing in the NFL. Of course, i find the former more interesting to follow from the comfort of my armchair.

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Re:Zero-G is bad long term, but what about 1/6-G?

[bthecohen]

You hit the nail on the head: this is perhaps the most fundamental unanswered question in life support for space exploration. We simply have no idea.

Originally, the ISS was slated to have a module called the Centrifuge Accommodations Module. [wikipedia.org] It was intended to help answer this question. It contained a large centrifuge that could hold 2-foot-tall animal cages and simulate anywhere from zero to 2g. It would have been one of the most essential experiments on the station, because there is really no way to collect data on varying levels of microgravity on living organisms other than putting a centrifuge in zero g. Unfortunately, the (mostly assembled) module was cancelled in 2005.

The engineering implications for interplanetary missions are profound, in that it might be vastly more expensive to build a 1g artificial gravity centrifuge than, as you said, a 1/6g one. But we currently have absolutely no way of knowing how many Gs we need. It's a very tough problem.