May 15, 2010
Weightlessness Messes Up Immune Genes?
Weightlessness (or higher background radiation) in space messed up genes that control stress and immune response. Yet another example of how we need to be able to genetically reengineer ourselves in order to move off-planet. We evolved on this planet and are adapted to a pretty narrow range of conditions.
Tucson, Ariz. -- Astronauts are known to have a higher risk of getting sick compared to their Earth-bound peers. The stresses that go with weightlessness, confined crew quarters, being away from family and friends and a busy work schedule - all the while not getting enough sleep - are known to wreak havoc on the immune system.
A research group led by immunobiologist Ty Lebsack at the University of Arizona has discovered that spaceflight changes the activity of genes controlling immune and stress response, perhaps leading to more sickness.
Shooting humans up into space on current generation (or even next generation) chemical rockets is just a show. It accomplishes extremely little. That we even do it demonstrates the excessively high discount rate of most humans. Said discount rate a product of an evolutionary past which required much more shorter term planning than today). If we really wanted to go move off world we would need to spend decades developing a wide range of really advanced technologies needed to make the move. We need nanotech, genetic engineering of food and fiber crops, genetic engineering of plants organisms that would clean our environment. robots, AI, and fusion energy for starters.
Just 13 days riding on the (obsolete and bad design) Space Shuttle was enough to wack out gene expression in mouse thymus tissue.
Lebsack and his colleagues focused their study on the thymus gland, the organ that serves as a "factory" and "training academy" for T-cells that are key players of the immune system. They compared gene-expression patterns in thymuses from four healthy mice that had spent 13 days aboard NASA's STS-118 Endeavor Space Shuttle to those from an equal number of control mice on the ground.
Their finding: 970 individual genes in the thymus of space-flown mice were up or down-regulated by a 1.5 fold change or greater. When these changes were averaged, 12 genes in the thymus tissue of all four space-flown mice were significantly up or down-regulated. "The altered genes we observed were found to primarily affect signaling molecules that play roles in programmed cell death and regulate how the body responds to stress," Lebsack said.
We also need genetic engineering for maintaining bone mass, muscle mass, and joint mass among other things. The higher level of radition we'd experience on a trip to Mars argues for waiting for cures for cancer before trying to colonize Mars.
Just one of the many reason I am ALL about putting OUR house in order first!
Until then, robotic missions are just fine with me - although it seems like a no brainer to get - at the very least - a space station up that could have artificial gravity through rotation.
(of course studies would have to be done to see if that helps with more than just bone density maintenance)
Even if given the chance - I don't think I'd be interested in anything but a short trip to visit the Moon - in my current, limited, form.
This is also why I believe it makes more sense to think of advanced alien travelers - as sophisticated cyborgs - rather than true "natural" exobiological entities.
How this physical change has affected their psychological outlook - is itself an interesting subject - but I would assume - just like with Humans - it would tend to make them more dispassionate and more calculated about their actions.
"Yet another example of how we need to be able to genetically reengineer ourselves in order to move off-planet."
No, it's another example showing that some level of spin gravity is needed for long term residence for in-space habitats. Either rotation of the habitat structure or an internal centrifuge should suffice. For example, a recent study with subjects undergoing long term bed rest, which produces many of the effects of weightlessness, showed that just one hour per day on a centrifuge at 2.5g prevented any bone loss. See
Many more such studies are needed, especially in space, but most likely such straight-forward measures will prevent other problems like the one you mention here and easily allow for indefinite space residency.
With respect to radiation, increased shielding will suffice just as our atmosphere provides sufficient protection to the passengers flying on spaceship earth (the earth's magnetic field, which occasionally disappears during a reversal, is of secondary importance). On the Moon and planetary surfaces, shielding material is abundantly available. Space vehicles can use the straight-forward approach of surrounding their living areas with their water and fuel tanks, food stuffs, and other hydrogen rich materials, which can provide excellent protection. Long term in-space habitats (and cyclers to Mars) can build up their shielding over time to as much as needed.
"Shooting humans up into space on current generation (or even next generation) chemical rockets is just a show. It accomplishes extremely little."
No, in fact it accomplishes a lot in terms of taking the first steps in learning how to expand humanity into the solar system. Propellants contribute only a minute fraction to the current high cost of going to space. Low launch rates and throwing away the vehicles is what costs. Fully reusable, high launch rate vehicles are within reach. (The new suborbital spaceships will provide great lessons in building and operating fly-return-refuel-refly vehicles.) Chemical vehicles are quite sufficient to allow for the incremental, step-by-step process needed for learning how to travel, build, and live permanently in space.