One of the biggest hazards that lie beyond the protective layer of Earth atmosphere and magnetic field is space radiation. These deadly cosmic rays come from two sources. First are solar energetic particles that are ejected from the sun via its solar flares and coronal mass ejections. Second are galactic cosmic rays that were created outside our solar system and amount of its presence is directly related to the periods of Suns high and low activity. Unprotected long term exposure to such conditions can cause wide array of health problems, such as damaged DNA, risk of cancer, cataracts, neurological disorders and other mortality risks.
In a quest to find solution for long term human habitation in space, Earths scientist have long ago started testing effects of Space radiation to living organisms. Since late 1940’s until today exactly twenty nine non-human primates have been sent into space - 17 by US spacecrafts and 12 by Russians. Majority of those flights happened in lower Earth orbits and were not primarily designed to test for radiation effects.
One of the main NASA programs designed to test long term space habitation started in 1966 with the launch of the Biosatellite rockets. First two capsules carried varied specimens of fruit flies, frog eggs, bacteria and other life forms. Third mission in 1969 carried a 6-kg male pig-tailed monkey Bonny and was designed to test her brain functions, cardiovascular status and performance on a 30 day long mission. Her capsule was brought down to Earth only 8 days later due her detonation health state.
Protection from the space radiation can be achieved in several ways, but there are no 100% safe solutions. Space craft shielding can be effective against some types of radiation, but metal and hydrogen rich plastics solutions can often become emitters of secondary radiation. Liquid hydrogen and water compartments can be good shielding against radiation but those materials are consumable and therefore can not be permanent. The last technical solution is use of electromagnetic field witch would simulate Earth’s magnetic shield. Lastly some researches are instigating potential medical solution to radiation, with goal to strengthen human metabolism and help him repair radiation damage.
In late 2010 NASA announced research with a mission to explore radiation effects in possible human mission to Mars. They proposed test in witch 18 to 28 small squirrel monkeys would over long period of time receive small doses of radiation. News of this research created massive public outcry and various animal-rights organizations mounted several aggressive campaigns against the experiment. In December 2010 NASA responded that they will postpone monkey radiation tests and are still in belief that such animal testing would greatly expand our knowledge of outer space conditions and minimize future human loss of life.