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SCIENCE: Mars a Dangerous Destination for Humans

Cristina Hernández* - Tierramérica

SAN FRANCISCO, USA, Feb 24 2004 (IPS) - The crew chosen for the first human voyage to Mars must learn to deal with obligatory confinement and to survive amidst serious health threats during an extended period, as long as three years, 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 consists almost completely of carbon dioxide.

The announcement in January by U.S. President George W. Bush of a possible manned mission to the neighbouring planet was enough to set some enthusiasts to fantasize about packing their bags.

The first thing is to establish 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 would push back 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 missions to the Moon and to 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 can 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, scientists 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, could reduce the health risks after prolonged exposure.

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 Mars Society’s Zubrin, an astronaut travelling 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 Centre.

One such lesson is that astronauts need to exercise to prevent muscular atrophy and to improve their cardiovascular functions.

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 budgets and the development of new technologies," he said, though if these requirements were 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 will not be chosen until 10 or 20 years from now," Petty said.

(* Cristina Hernández is a Tierramérica contributor. Originally published Feb. 21 by Latin American newspapers that are part of the Tierramérica network. Tierramérica is a specialised news service produced by IPS with the backing of the United Nations Development Programme and the United Nations Environment Programme.)