— The dangers associated with a manned mission to Mars are formidable.
— Space radiation, microgravity and psychological implications could push the Red Planet beyond our reach.
— But science is finding new ways to lessen the impact of the worst space will throw at our delicate physiology.
When NASA's 30-year Space Shuttle Program ends on Thursday as Atlantis touches down for the last time, space-watchers will be looking toward our next step into space.
We've already 'done' the moon, but Mars still beckons like some interplanetary Brigadoon; visible through the eyes of clever little rovers and orbiters, but just beyond the reach of human footsteps.
Despite several decades of research and development, a long-duration voyage to Mars is still on the drawing board. Putting aside the enormous financial costs of an interplanetary mission, there are still major engineering and physiological hurdles to overcome.
The combined effects of background cosmic rays from extragalactic sources and extreme radiation events from the sun make space travel too hazardous for an estimated six months there and six months return.
"The estimate now is you would exceed acceptable levels of fatal cancer," said Francis Cucinotta, chief scientist for NASA's space radiation program at the Johnson Space Center in Houston. "That's just cancer. We also worry about effects of radiation on the heart and the central nervous system."
Cucinotta says these estimates do take into account protective shielding around a crew vehicle, probably some form of polyethylene plastic. Lead shields actually create secondary radiation when struck by cosmic rays, while water, perhaps the best form of protection, would have to be several meters thick to get enough protection. ("Houston calling Water Balloon 1, do you copy?")
Lead and water, in any case, are very heavy for the quantities that would be required, making them an expensive shielding to launch.
Solution: Pick astronauts that have never smoked, never been around smokers, and have a built-in genetic resistance to radiation damage. "We didn't know about this (ability) five or ten years ago, we should have an answer in another ten or 15 years," Cucinotta said.
Genetic protection plus a special shielded shelter may do the trick.