About Space Radiation
NASA Space Radiation Element
Once astronauts venture beyond Earth's protective atmosphere, they may be exposed to the high energy charged particles of galactic cosmic rays and solar particle events (SPE) and secondary protons and neutrons. Because of their ionization patterns in biomolecules, cells and tissues are distinct from terrestrial radiation, the resulting biological effects are poorly understood, and the amount of risk involved is subject to large uncertainties.
The major goal of NASA's Space Radiation Program Element (SRPE) is to develop the knowledge base required by NASA to accurately predict and efficiently manage the radiation risk of human spaceflight.
The knowledge base has been built over time and continues to be augmented by a peer-reviewed, largely ground-based research program utilizing the NASA Space Radiation Laboratory at the Brookhaven National Laboratory and the Loma Linda University Proton Treatment Center. Experiments performed at these facilities mimic conditions of the space radiation environment and contribute to the development of risk models, a greater knowledge of the genetic consequences of heavy ions to biological systems, and better methods of spacecraft shielding.
Ionizing radiation travels through living tissues, depositing energy that causes structural damage to DNA and alters many cellular processes. Current research sponsored by NASA seeks an understanding of DNA structural and functional changes caused by radiation, basic metabolic controls known to be modulated by radiation; genomic instability; changes to tissue structure; and “bystander” or non-targeted effects.
NASA has identified the following health concerns as its highest research priorities:
- Risk of Radiation Carcinogenesis from Space Radiation - increased risk of cancers.
- Risk of Acute or Late Central Nervous System Effects from Space Radiation - changes in motor function and behavior or neurological disorders.
- Risk of Degenerative Tissue or Other Health Effects from Space Radiation - other degenerative tissue defects such as cataracts, circulatory diseases, and digestive diseases.
- Acute Radiation Risks from Space Radiation - prodromal risks, significant skin injury, or death from a major solar event or combination solar/galactic cosmic ray event that jeopardizes crew and mission survival.
Research to be supported seeks to: reduce the uncertainties in risk predictions for cancer and acute radiation risks; provide the necessary data and knowledge to develop risk projection models for central nervous system (CNS) and other degenerative tissue risks; and significantly advance the understanding of the mechanisms of biological damage that underlie radiation health risks. This research is also expected to provide a substantial contribution to the scientific basis for eventual development of biological countermeasures to these risks as appropriate.
Because there are no human epidemiological data for these radiation types, risk estimation must be derived from mechanistic understanding based on radiation physics, and on molecular, cellular, tissue, and organismal radiation biology related to cancer, risk to the central nervous system, and other risks of concern to NASA.
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