A hypothesis on biological protection from space radiation through the use of new therapeutic gases as medical counter measures

Galactic Cosmic Rays (GCR), solar energetic particles (SEP), and trapped energetic particles in a planetary magnetic field are natural sources of radiation in space. GCRs consist of highly energetic nuclei, predominately protons and He, but also trace amounts of C, O, Ne, Si, Ca, and Fe ions. Particle energies can range from 100 MeV to 10 GeV per nucleon [1]. Although the high charge and energy (HZE) nuclei are in trace amounts, they are still of concern because they can cause more damage than protons since they are more highly ionizing. As well, even though particle fluxes are typically low, they are chronic and can significantly increase with solar events [1]. Furthermore, GCRs and SEPs impinging on shielding material, atmosphere, or surface of a planet or satellite can produce secondary radiation, including energetic neutrons, from nuclear fragmentation of the primary ion and target atoms. This can introduce an additional component to the radiation field which makes shielding from HZE quite challenging and poses one of the principal unknowns in understanding the HZE effects with human tissue [2]. Furthermore, while our bodies do possess a natural repair mechanism, radiation with a high linear energy transfer (LET) rate, like space radiation, is attributed to be more likely to cause double strand breaks in DNA that are relatively more difficult for our natural repair mechanisms to fix correctly [3]. While a week or month of this radiation at the dose rates naturally present likely will not have serious consequences, several year durations in space could. The traditional paradigm for radiation protection is to minimize exposure time, maximize distance from radiation sources, and use shielding to attenuate and absorb radiation before it can deposit its energy in humans. In regards to minimizing exposure time, new propulsive technologies could reduce trip times but have yet to be developed and would not address the ability to remain at a location for long durations.