Mars Journey Likely To Test Human Risk Limits

Mars: NASA
HOUSTON—As NASA charts a course to Mars for human explorers with ever more capable hardware and software systems, policymakers, mission managers and those who launch face some tough ethical issues.Those issues include the physical and psychological risks astronauts are sure to face as they are exposed to higher levels of radiation, possible severe or even fatal illness or injury, and personal tragedies unfolding back on Earth.Though astronaut crews typically spend five to seven months aboard the International Space Station, in an emergency they are only 250 mi. and several hours from a return to Earth. The Apollo missions to the Moon lasted only six to 12 days. The human journey to Mars, which NASA intends to lead in the 2030s, will span two to three years and range millions of miles from Earth.

Great tragedy will compete with national pride as a dividend among even the most ardent supporters.
“You really have to ask, have we taken a good look at all the known risks? Do we understand what the potential unknowns are? Have we beaten the risks down to a level that we would actually feel comfortable asking someone to go?” Ellen Stofan, NASA’s former chief scientist, told those gathered at the Newseum in Washington for the May 16 forum “On the Launch Pad: Return to Deep Space,” sponsored by The Atlantic.
“The risk is never going to be zero,” Stofan noted. “They are explorers. They are pushing the frontier. But let’s do it responsibly.”

Some of the risks NASA is well aware of include bone and muscle loss in the absence of gravity and degraded vision—all obstacles the agency has confronted during the space shuttle and space station eras. Earth and planetary science missions have exposed the threat posed by solar and galactic radiation once astronauts move beyond the shield-like protections afforded by the Earth’s atmosphere and magnetic field.
NASA has established daily exercise regimes and nutritional requirements to help offset weakened bones and muscles. Prescriptive glasses issued to astronauts before they launch can offset vision impairments whose root cause continues to puzzle experts. NASA’s Curiosity rover, with its Radiation Assessment Detector, has helped to ease but not erase the threat posed by radiation, whose effects may not surface until a mission is long over. NASA currently adheres to lifetime radiation exposure limits for its astronauts, depending on gender and age. But they may have to be raised if astronauts are to venture into deep space for years at a time.
The harmful effects from a mixed field of solar and galactic radiation, difficult to recreate on Earth, have proven challenging to define even with modeling, according to Kris Lehnhardt, an assistant professor of emergency medicine at the George Washington University School of Medicine and Health Sciences.
The challenge of solving the radiation threat may help to justify NASA’s proposed Deep Space Gateway, a lunar orbiting public/private crewed space station. That is where cell and tissues samples and repair strategies could be exposed and assessed in the search for countermeasures of value in terrestrial medicine, as well as to Red Planet explorers, Stofan and Lehnhardt said.
Planners also cannot afford to overlook the psychological effects, says Mike Lopez-Alegria, a retired U.S. Navy test pilot and NASA astronaut who spent seven months aboard the International Space Station in 2006-07. During his many weeks on the ISS, he was able to stay in touch with family and friends through email and an internet phone with minimal time delays, greatly easing feelings of separation, Lopez-Alegria said.
But communications time delays will grow to as much as 20 min. each way at Mars, and the visual connection to Earth possible from the ISS and the Moon will fall away, he said.
“Looking out at the planet is incredibly soothing,” said Lopez-Alegria, describing how station crews liked to break up demanding work schedules by gathering in the small European cupola observation deck to look out at the Earth below. “It’s incredibly beautiful. People on the way to Mars will not be able to do that. At some point, even if they can look back, they will not be able to tell which dot is the Earth. I think that feeling is very, very different than anything we have experienced.”
Recalling the transition of NASA’s astronaut corps from one- to two-week-long space shuttle flights to weeks and months aboard Russia’s Mir space station and finally the ISS, Lopez-Alegria championed the training value of Earthly field exercises and time spent aboard the undersea Aquarius lab off Florida’s Atlantic coast as part of NASA’s Extreme Environmental Mission Operations program.
Each helped astronauts identify coping techniques when isolated and physically stressed by temperature extremes and restricted diets, he said.
Sheyna Gifford, one of six participants in a yearlong, 2015-16 Mars mission analogue sponsored by the University of Hawaii’s HI-SEAS project on the high-altitude slopes of the Mauna Loa volcano, echoed Lopez-Alegria’s sentiments.
During the lengthy exercise, the NASA medical researcher was notified of her grandmother’s death, an experience she weathered in part by paying respects while watching a delayed video of her close relative in the confines of the 1,200-sq.-ft. HI-SEAS shelter.
“That is not something you ever want to do, but it’s something you do and life goes on,” Gifford told the forum. “That morning I got up and did my job.”
The experience helped to inform Gifford and other forum participants of another unpleasant prospect facing a small deep-space exploration crew—coping with the impairment or loss of a colleague from illness or injury during the journey.
“What do you do if one of your crewmembers is sick or injured and you can’t save them? You are transiting to Mars. You are halfway there. Someone becomes sick, and you are trying to make them better,” explained Lehnhardt. “You are using up all your resources to do it. At what point do you stop taking care of that person and start saving your resources because your mission comes first?”
The possibility and the psychological consequences deserve to be explored, as part of what’s called operational medicine, Gifford said.
“The idea is you have to have these discussions before you go, think through the parameters and scenarios,” Lehnhardt said. “You have to be prepared that something terrible may happen. You have to be able and willing to deal with it.”

Source: May 17, 2017 Mark Carreau | Aerospace Daily & Defense Report

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