Previous investigations on bacteriophages, bacterial spores, yeast, plant seed, insect embryos, rats, and mice have shown serious effects such as chromosomal damage, cell death, or malfunctions caused by HZE particles passing through the biological material. Irrespective of their rarity, HZE particles represent a considerable risk for humans in space.
The specific effects of HZE particles in humans are not well documented. In ground-based experiments it has been proven that HZE particles induce chromosomal aberrations in human lymphocytes. Thus, this investigation studied chromosomal aberrations in human blood lymphocytes to assess the mutagenic potential of space radiation in man.
Previous investigations were conducted by the same investigator team, using blood from eighteen astronauts and cosmonauts flown on board the Space Shuttle and Mir Space Station. Throughout the study, a postflight increase of chromosomal aberrations in lymphocytes was evident for the long-duration crewmembers. Lymphocytes collected from astronauts and cosmonauts who stayed more than 100 days in Earth orbit showed elevated frequencies of dicentric chromosomes, a typical chromosomal aberration induced by ionizing radiation. In difference to these previous investigations, new multi-color banding fluorescence in situ hybridization (mBAND) and multi-color fluorescence in situ hybrididization (mFISH) techniques were used to analyze the samples.
The compilation of results should provide information about chromosomal aberrations in peripheral lymphocytes of crewmembers exposed to space radiation. The results will enable a better assessment of the genetic risk of humans in space and in consequence, will help to optimize radiation shielding. The data also allows for calculations of aberration frequencies expected during deep-space missions.
Blood draws were scheduled preflight, at L-10 (10 days before launch), and postflight as close to landing as possible (R+0 or R+3, depending on the landing site). Twenty-four crewmembers gave their consent to participate in this study: 11 crewmembers on short-duration Space Shuttle missions, and 13 subjects on long-duration missions of several months on board the International Space Station (ISS).
This investigation has been performed on ISS Expeditions 6-11. In each Expedition where the experiment has been conducted, preflight and postflight blood samples were drawn from each crewmember. To ensure high-quality results, the blood samples arrived at the Principal Investigator's laboratory in Essen, Germany within 72 hours after collection. Researchers are currently measuring changes in the genetic material and analyzing their significance and will release preliminary conclusions soon. From this study scientists may be able to better assess risk factors for genetic damage in space. Understanding and reducing the risk of radiation is important for safe long-duration travel in space, including stays on the moon and journeys to Mars.
|Mission||Launch/Start Date||Landing/End Date||Duration|
|Expedition 10||10/13/2004||04/24/2005||193 days|
|Expedition 11||04/14/2005||10/10/2005||179 days|
|Expedition 6||11/23/2002||05/03/2003||161 days|
|Expedition 7||04/25/2003||10/27/2003||185 days|
|Expedition 8||10/18/2003||04/29/2004||195 days|
|Expedition 9||04/18/2004||10/23/2004||188 days|