The astronauts must be protected by huge water tanks
After decades of watching astronauts orbit the Earth, space visionaries have reason for optimism. NASA and other agencies are working with the White House on a new pattern of discoveries.
Among the targets will be Mars or the Moon - or whether at all one of the plans will take off remains to be seen. For space enthusiasts, just engaging with the mission definition will give reason for hope.
After the crash of the space shuttle "Columbia", the USA is considering its steps in the field of space exploration - should it return to missions to the moon or should it set a new goal: Mars. New measurements carried out by the Odyssey spacecraft, which has been orbiting Mars for the past two years, reveal that although the Martian atmosphere does not provide protection from cosmic radiation (unlike the Earth's atmosphere), it will be possible to send astronauts to the planet to explore the surface and return safely.
Researchers from the Biomedical Space Research Institute presented the new data at the American Geophysical Union conference, currently taking place in San Francisco. The main problem that the researchers examined is the level of radiation to which the astronauts will be exposed. According to Dr. Kari Zeitlin, the astronauts will be exposed on their journey to Mars and back - and on the surface of the planet - to a dose of radiation many times greater than the radiation to which astronauts working on the International Space Station orbiting the Earth are exposed. This is, in part, because while the space station spends six months, the journey to Mars and back will take almost three years.
It turns out that the radiation problem is one of the reasons that may prevent a trip to Mars. An article published in the "New York Times" claims that the average American is exposed to a radiation level of 350 millirams per year (a unit of measurement for the level of radiation absorbed by the body), as a result of exposure to airplanes, X-rays, television and even rocks that emit radiation (see diagram). The astronauts who flew nine days to the moon in the "Apollo 14" mission absorbed radiation of 1,140 millirams, equivalent to the exposure of three human years on Earth. The astronauts who spent 87 days on the International Space Station were exposed to 17,800 millirams of radiation, equivalent to the exposure of 50 human years on Earth. According to estimates, on the journey to Mars the astronauts will be exposed to radiation of 130,000 millirams (about 400 years of exposure to radiation on Earth).
"Such a large dose of radiation raises questions about its biological effects, and these have never been tested," Dr. Zeitlin told the BBC, adding that not only the level of radiation is problematic but also the type of radiation. "This is cosmic radiation, coming from all directions and from all ends of the galaxy." According to him, the intense cosmic radiation may cause new types of cancer, eye problems and damage to the nervous system. To try to illustrate the intensity of the radiation, the scientists said that the advanced electronic instruments installed on the surface of "Odyssea" to measure the radiation levels around Mars, was itself damaged by radiation in October, following the intense solar flares.
But Dr. Zeitlin claims that despite the findings, these are risks that can be dealt with and humans will be able to fly to Mars relatively safely. According to him, the astronauts will be able to protect themselves from the radiation if they use the caves and spaces on the surface of Mars. In addition, he suggests that the astronauts use special materials that they will bring from Earth, which will help them reduce the radiation around them. But even such a solution may turn out to be problematic.
On Earth, materials such as concrete or lead are used to protect against radiation, but the cost of flying them to Mars is enormous. That's why the scientists are checking if it is possible to protect the astronauts by surrounding them with a giant water bubble, which they will have to take with them on the long journey anyway.
Despite Dr. Zeitlin's statements, the first manned flight to Mars is probably still far away. NASA's chief scientist, John Grunsfeld, said that studies examining the possible damage caused by radiation to human cells will last at least five years.
