But it is the human element that is both the most important, and the most vulnerable, part of the mission. Before sending astronauts to Mars, scientists will have to solve the numerous medical and biological problems associated with deep space flight.
The mission to Mars will feature entirely new forms of medical and biological support, because the time-tested methods developed for orbital flights do not apply to inter-planetary travel. On top of this are the challenges of impaired telecommunications, variations in gravity and a limited time for acclimatization prior to landing on the planet, as well as high radiation and a lack of magnetic fields.
From January 8, 1994 to March 22, 1995, Russian Cosmonaut Dr. Valery Polyakov spent a total of 437 days, 17 hours, 58 minutes aboard the Mir space station. His epic flight showed that there are no serious medical-biological effects of long-duration space flights.
Anatoly Grigoryev, Member of the Russian Academy of Sciences and Director of the Institute of Medical and Biological Studies, said no serious changes in the human body had been revealed, so there were no obstacles to longer space flights and a possible mission to Mars.
However, everything must be done to shield astronauts from solar and cosmic radiation during the two-year flight, as accumulated radiation could exceed safe levels. Developers are currently focusing on structural protection, and are planning to shield the astronauts by placing fuel, water and food tanks around the crew module. This would guarantee protection equivalent to 80-100 grams per square centimeter.
But astronauts could also be irradiated on the planet's surface. The Russian-made High-Energy Neutron Detector (HEND), installed on NASA's Mars Odyssey spacecraft, showed that the intensity of neutron radiation reflected from the Red Planet's surface during solar flares can increase several hundred times, and even threaten astronauts' lives.
Consequently, landings could only take place while solar radiation was relatively low.
Although astronauts now use water to heat tasty sublimated (dried) food, food diversity remains a major problem. At first, scientists wanted to breed birds to lay eggs for astronauts to eat. However, chickens proved unable to adapt to zero gravity. Fish and mollusks, which adapt more easily, grow too slowly to provide a regular food supply.
So much for animal protein. Scientists have been more successful with vegetables. Experts working for the Institute of Medical and Biological Studies have developed a prototype "space truck garden" - a kind of minature green house resembling a cylinder containing fertilizer-covered rollers. The inner surface of the cylinder is covered with hundreds of red and blue diodes, which act as solar rays. The rollers, on which the plants grow, slowly rotate, bringing their tops closer to the light source to simulate day and night. Some rollers can be harvested, while others are still covered with shrubs, thus providing a regualr supply of food.
The experimental truck garden would allow astronauts to harvest 200 grams of vegetables every four days and would also provide additional oxygen.
Water is another problem. Each astronaut needs approximately 2.5 liters per day. Consequently, the spacecraft will have to carry several tons of water to the Red Planet, as well as water-regeneration systems to replenish supplies. Ideally, a closed-cycle physical-chemical system would ensure the turnover of substances. Unfortunately, such systems are unlikely to appear in the near future.
Psychological problems should not be overlooked either. It will take 20 to 30 minutes for radio signals to travel the vast distance between Mars and the Earth, and vice versa. Mission control will therefore be unable to intervene in case of emergency. At best, it could act as a kind of consultant, offering advice. The slowness of communications, however, means that most decisions would have to be made by the crew themselves.
Daunting though these challenges are, Russian scientists will try to solve many of them during the Mars-500 experiment - a simulated Mars mission lasting 520 days.
Five volunteers have already been chosen from among 150 applicants to participate in the simulated space flight. "Blast off" has been scheduled for the last quarter of 2007. Although there were 16 women amongst the original applicants, it is thought that the physical and psychological differences between the sexes give men a far better chance of reaching Mars first.
The six-member crew will spend almost two years inside an experimental research complex comprising five modules. They will experience the daily routine of professional astronauts, including medicals, workouts and maintenance of station equipment, and will have to cope with simulated emergencies, arising both from human error and equipment failure.
One of the modules will simulate the surface of Mars.
Scientists will closely follow the behavior and relations between crewmembers in order to improve their understanding of the psychological challenges of long space flights.
However, only four astronauts will eventually fly to Mars.
The United States has also started recruiting volunteers for a simulated four-month space flight, after learning about the Russian plans.
Yury Zaitsev is an academic adviser with the Russian Academy of Engineering Sciences.
The opinions expressed in this article are the author's and do not necessarily represent those of RIA Novosti.
