AP Photo/NASA and Hubble Heritage Team

Space Radiation Hinders NASA’s Mars Ambitions

September 17, 2009 02:45 PM
by Anita Gutierrez-Folch
Faced with proposed budget cuts and a need for new technologies that would protect astronauts from radiation, NASA may have to put Mars exploration on hold.

Mars—“not an easy place to visit”

NASA’s plans to send astronauts on an exploratory mission to Mars orbit may be shelved due to the threat of radiation. A White House panel set to review NASA’s human space flight missions “suggest[ed] sending astronauts to one of Mars's moons, Phobos or Deimos,” David Shiga reports for New Scientist. But the galactic cosmic rays outside low-Earth orbit “can slice through DNA molecules when they pass through living cells,” leading to cancer, Shiga explains.

According to the summary report of the Review of U.S. Human Space Flight Plans Committee released last week, “Mars is not an easy place to visit with existing technology and without a substantial investment of resources.” Although the report referred to Mars as “the most scientifically interesting destination in the inner solar system”—echoing the sentiments of Michael Collins and Buzz Aldrin at the 40th anniversary commemoration of the first moon landing—it concluded that Mars “is not the best first destination.”

If astronauts could reach Mars’ moons, they would be able to “use remote-controlled robots to explore the Martian surface and retrieve samples—from the planet as well as the moon itself—for later close-up study on Earth,” Shiga explains. Nevertheless, space radiation, composed mostly of protons and atomic nuclei, poses a real threat for astronauts. According to a study quoted by New Scientist in 2006, these particles actually “cause twice as much serious damage to DNA than [previously] expected,” exposing astronauts to grave risks of cancer and other diseases. 

As Shiga explains, Earth’s atmosphere and magnetic field protect people on the ground—and astronauts on the International Space Station—from the harmful effects of radiation. Radiation exposure during trips to the moon is also low: The missions are short and the moon itself offers protection from particles. On the other hand, planets such as Mars, located beyond low-Earth orbit, are fully exposed to galactic cosmic rays and their destructive radiation. According to calculations made by Frank Cucinotta, chief scientist for radiation studies at NASA's Johnson Space Center in Houston, Texas, a trip to Mars orbit would not comply with NASA’s safety rules for astronauts, which “aim to keep each astronaut's lifetime risk of fatal cancer from space radiation below 3 per cent,” New Scientist reports.

Background: Budget cuts could hinder further developments

As New Scientist indicates, NASA is developing a series of possible solutions to shield astronauts from dangerous space radiation. Given that shields made of plastic or aluminum would most likely be impractical due to their weight, NASA is exploring alternative technologies such as “deflector” shields of plasma to protect astronauts and spacecrafts from radiation.

In August, however, President Obama announced a $3 billion budget cut affecting NASA’s human space flight program from 2011 to 2031, a measure that could seal the fate of human space exploration for the time being, Rachel Courtland reports for New Scientist. The budget committee estimated that NASA “will need a much larger infusion, of about $50 billion over and above current projections in the next decade, to meet its targets.” Though the budget cut is still open to review, its implications could be fatal for the development of future manned space exploration. As Scott Pace, director of the Space Policy Institute at George Washington University, told New Scientist, “[I]f this [$3 billion loss] becomes permanent, it's over, there is no manned exploration programme.”

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