| | New Scientist is reporting interesting research by former astronaut Millie Hughes-Fulford that appears to pinpoint how weightlessness impairs the immune system.
Her team at UC San Francisco has identified a "specific signal pathway that is not working in the absence of gravity." The net result is that the immune system's T-cells are not properly activated. According to the EurekAlert release, "there are only two known situations in which T-cell function is so severely compromised: HIV infection and weightlessness."
In light of such an observation, I can't help wondering if AIDS research will somehow end up helping human spaceflight, or vice-versa. It's hard to justify, up front, a lot of space exploration and research (or any other kind of research), because you're delving into the unknown and don't know what you'll find. Nevertheless, the history of hundreds of years of exploration and scientific research shows we usually find something unexpected, which may be disappointing at first but ultimately much more valuable than what was sought.
In fact, most breakthrough research occurs by identifying unexpected connections between seemingly unrelated things. Perhaps this effect of weightlessness on T-cells will lead to a new insight on how to strengthen the immune system against HIV.
In any case, the best example of the value of unexpected connections is astronomy, which has a long history of tying together observations of distant stars and planets to physics and math discoveries usable here on Earth. In the same way, I hope NASA will find a way to continue microgravity research on a large and accessible scale, because I'm sure it will eventually yield a big pay-off (Hughes-Fulford's group is developing a follow-up experiment for flight next year).
In general, spaceflight is known to have a number of physiological effects. Early on, a lot of the research was directed toward the effects of high g-loadings on the body, using rocket sleds and centrifuges, since accelerations/decelerations in capsules were much higher than on the shuttle, which was limited to 3g (I'm not sure what NASA is specifying for its new Crew Exploration Vehicle capsule).
In the 70s, space medicine research became more focused on the effects of weightlessness. The U.S. did a lot of physiological research on Skylab, and the Soviet Union went further with its long series of stations (Salyuts and Mir). Some of the effects from a lack of gravity include loss of muscle mass, decalcification of bones, and the redistribution of fluids upward in the body. Many astronauts also experience spacesickness, at least at first.
Of course, radiation exposure is a key concern with spaceflight, in two ways. Sudden events like solar flares have the potential to produce lethal radiation; this was a real danger to Apollo astronauts travelling to the Moon. Long-term radiation exposure is also a danger to astronauts (and even to high-flying airline crews). There have been rumors of excessive cancer rates in the Soviet program, at least (which amassed many more days in space than the U.S.), but privacy concerns have limited publicly-available data on this.
The National Space Biological Research Institute has a helpful listing of many of the areas of space medicine research. They've also put online a subtantial illustrated reference, Human Physiology in Space. |
| | Posted 10/20/2005 6:51 PM - 83 Views - 2 eProps - 1 Comment
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