UND's Space Studies: Excerpt from “Mars: The Race to the Red Planet” – National Geographic Magazine, November 2016 by Joel Achenbach
"What NASA has been doing, besides designing its own rocket to go to Mars, is a lot of work on how to take care of the passengers. In March, for example, astronaut Scott Kelly and Russian cosmonaut Mikhail Kornienko returned to Earth after 340 days on the space station. On their “One-Year Mission” they served as guinea pigs for studies of what long stints in space (a round-trip to Mars might take nearly three years) do to the human body and mind. As they plunged back into the atmosphere, Kornienko recalls, their Soyuz capsule was rattling like a car on a cobblestone road, and fist-size sparks from the flaming heat shield were flying past the portholes. He and Kelly could barely breathe: After a year of weightlessness their lungs and chest muscles were weak. And once they landed on the steppes of Kazakhstan, they could barely walk. The ground crew carried them from the capsule, for fear they might stumble and break a bone. In May, Kelly was still saying that his feet hurt.
Hollywood movies convey the fun of weightlessness. Interviews with Kelly and Kornienko from the space station hint at the other side. Their faces are puffy, because fluid doesn’t drain out of them. Their arms are folded across their chests, lest they extend straight ahead in the dreaded “zombie pose.” Astronauts can get used to strapping themselves onto a suction toilet and even, Kornienko says, to a whole year of wiping off with a wet washcloth, for lack of a shower. On a much longer, much more hazardous Mars journey, in which Earth is not 250 miles but millions of miles away, with no option to turn back or bail out, what space can do to a human body could be a huge problem. “They’re going to be sick when they get there,” says Jennifer Fogarty, deputy chief scientist for the Human Research Program at NASA’s Johnson Space Center, in Houston.
Bones waste away in zero gravity: The rule of thumb is you lose one percent of your bone mass per month. Vigorous exercise helps, but the jumbo equipment used on the space station weighs too much for a Mars mission. Some astronauts on the station have also experienced serious vision impairment, apparently because fluid collects in the brain and presses on their eyeballs. The nightmare scenario is that astronauts land on Mars with blurred vision and brittle bones and immediately break a leg. Theoretically the risk could be reduced by spinning the spacecraft rapidly, replacing gravity with centrifugal force. But NASA engineers see that as adding too much complexity to an already challenging mission.
Radiation is another hazard. The astronauts on the space station are still mostly protected by Earth’s magnetic field. But on a journey to Mars they’d be vulnerable to radiation from solar flares and cosmic rays, which are high-energy particles coming from across the galaxy at nearly the speed of light. The latter especially can damage DNA and brain cells—which means astronauts could arrive on Mars a little dimmer, as well as blurry eyed and brittle boned. One possibility would be to line the habitat module with a thick layer of water, or even plants growing in soil, as a partial radiation shield. But so far nothing has been proved to solve the problem.
Just keeping astronauts supplied with drinkable water and breathable air is a challenge. One day at Johnson Space Center I met Kenny Todd, whose title is operations integration manager for the space station. He looked weary. It was midmorning, but he’d been at the office for many hours, working overnight to supervise one of the unheralded but critically important cargo flights. A conversation between the station and mission control squawked quietly from a speaker on his desk as we talked about urine, among other things.
Some of the water on the space station comes from filtering and recycling urine and sweat. But those filters can get clogged with calcium—from the astronauts’ dwindling bones—and the water sometimes gets contaminated by microbes. “Working with urine—it’s very finicky,” Todd said. The scrubbers that remove carbon dioxide from air break down too—like nearly every other device on the station. In low Earth orbit, that’s not critical; NASA can send up spare parts. A Mars-bound spacecraft would have only the spares it could carry with it. All the life-support equipment, Todd said, would need to be much more reliable than it is now, essentially unbreakable.
That doesn’t mean he doesn’t want to send people to Mars. Nor does he criticize the dreamers who are ready to blast off tomorrow morning. “You gotta start somewhere. You gotta start with dreaming,” Todd said. “And sometime in there, things become actual.” Which means a lot of things have to be figured out."
(See the entire article at: : http://www.nationalgeographic.com/magazine/2016/11/spacex-elon-musk-exploring-mars-planets-space-science/ )