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Mars a Dangerous Destination for Humans |
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By Cristina Hernández*
During a voyage to the "red planet", astronauts would be vulnerable to psychological problems due to confinement, genetic harm from radiation, and loss of bone mass as a result of zero gravity, say experts.
SAN FRANCISCO, United States - The crew chosen for the first human voyage to Mars must learn to deal with obligatory confinement and to survive amidst serious environmental threats for a prolonged period, say U.S. experts in space travel.
Every clear night, Mars appears, twinkling a reddish-yellow, tempting those who dream of setting foot on its surface. But behind its warm appearance is the reality of an average temperature of 53 degrees below zero Celsius and an atmosphere that is almost completely carbon dioxide.
The announcement in January by U.S. President George W. Bush of a possible manned mission to the neighboring planet was enough to set some enthusiasts to packing their bags.
"We've got to create a timetable" for the trip, Robert Zubrin, head of the International Mars Society, told Tierramérica.
"The Bush proposal is to go to the Moon before the end of the next decade and to Mars by mid-century. Our goal is to send a human to Mars by 2020," said the astronautical engineer and consultant to the U.S. National Aeronautics and Space Agency (NASA).
However, the distance that separates Earth from Mars, as well as the dangers that await a human crew, could pose challenges that delay the launch date.
"The main challenge is the length of time away from Earth, around three years. An 18-month stay (on Mars) would be required before they could lift off and come back," John Hoffman, physicist at the University of Texas at Dallas and member of NASA’s project Phoenix, which studies the geological history of water, told Tierramérica.
Because of the red planet's elliptical orbit, the distance between Earth and Mars varies dramatically.
In August 2003, Mars was a relatively close 56.3 million km from Earth, the shortest distance between the two in 60,000 years.
"Being gone for so long and with no return but one path could cause serious psychological problems," adds Hoffman, who has designed and built instruments used in mission to the Moon and Venus and to observe Halley's Comet.
The mental health risks involved with working in enclosed and isolated spaces include depression, anxiety, trauma and other neurological and psychiatric dysfunctions.
Also of concern is the high exposure to space radiation over the six or seven months of the trip and during the stay on Mars, Hoffman said.
Outside of the Earth's protective atmosphere, space radiation is so strong that it could remove the electrons of the atoms it hits. This could produce genetic damage to human cells.
Cancer, cataracts of the eyes and damage to the central nervous system are some of the possible effects.
According to NASA, on the International Space Station (ISS), which orbits the Earth at 386 km, they are studying the impacts of space travel on astronauts' health.
Radiation damage to chromosomes is being studied in blood samples from each member of the space station crew. Exposure to radiation can be reduced if the astronauts remain in the most protected areas of the ISS.
An appropriate diet, one high in antioxidants, like vitamins C and E, after prolonged exposure, could reduce the health risks.
The effects of different types of radiation are estimated in equivalent biological doses to measure not only quantity, but also the harm caused. This is measured using milliSieverts (mSv), with one mSv of space radiation approximately equivalent to receiving three chest x-rays. On Earth, we receive an average of two mSv every year just from background radiation.
According to NASA, the ISS crew receives 80 to 160 mSv during a six-month stay at the station.
Says the International Mars Society's Zubrin, an astronaut traveling to Mars would run the same risk of cancer as if he or she stayed on Earth and smoked two packs of cigarettes a day for three years.
The National Space Biomedical Research Institute (NSBRI), which works with NASA to reduce health risks during space travel, says that flights beyond the Earth's orbit lasting more than 12 months have shown that astronauts can lose up to 20 percent of their bone mass.
This increases the risk of bone fractures and of the formation of kidney stones, due to the release of calcium from the bones. The culprit behind this phenomenon is the lack of gravity.
Furthermore, says the NSBRI, prolonged space missions tend to mean reduced calorie intake, which could lead to loss of tissue, including muscles, and red blood cells.
The experiences of the ISS have taught us the essential facts about humans remaining in outer space for long periods of time, says John Ira Petty, spokesman for the Lyndon B. Johnson Space Center. One such lesson is that astronauts need to exercise to prevent muscular atrophy and to improve their cardiovascular functioning.
As for other human requirements, "Systems like the ones used on the ISS, to recycle water and generate oxygen, will be applicable to Mars," Petty told Tierramérica.
But "a manned mission to Mars depends on budgetary restrictions and the development of new technologies," he said. Once these requirements are met, a mission to the red planet could be launched every 25 months.
"We are a long way from a manned Mars mission. Probably new crew members would not be chosen until 10 or 20 years from now," Petty said.
* Cristina Hernández is a Tierramérica contributor.
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