Status of the Feasibility Study of Astronaut Standardized Career Dose Limits in Leo and the Outlook for Bleo

The International Academy of Astronautics has established, under the aegis of its “Human Spaceflight Coordinating Group” (HSFCG), a series of Cosmic Studies aimed at identifying a set of requirements for future human missions to Mars, within the context of future, global, cooperative scenarios. Among these, Cosmic Study SG 3.19/1.10 which is introduced in the present paper, considers the various career dose limits adopted by different space agencies for astronauts in Low Earth Orbit (LEO), having regard to the health risks imposed by the impingement of, naturally occurring, energetic particle radiation in this regime. These various limits raise the question as to whether the adoption of different limits can be justified or if they should, rather, be globally standardized, It is noted that standardization is not presently followed in the case of crew members of the International Space Station who individually adopt the career dose limits assigned by that agency with which they are affiliated. When a consensus is arrived at internationally regarding career dose limits for LEO, the question of how to assign such limits for missions Beyond Low Earth Orbit (BLEO) will be addressed. The deep space missions now envisioned to be implemented beyond the shielding provided by the geomagnetic field pose a different set of health risks to human crews than those prevailing in LEO and these risks will be carefully assessed and recommendations regarding them made. The biological responses of humans to high-energy particle radiation under microgravity conditions will, in addition, be investigated. An initial 25-page report describing the key scientific, technical and non-technical issues spinning off from the results relevant to human crews in LEO and BLEO, together with recommendations regarding the resolution, within a framework of multidisciplinary, international cooperation, of the related health hazards identified, will be prepared by all the Cosmic Study Team Members for joint submission to the Academy by October 2013. These initial recommendations will, thereafter, be prepared by the HSFCG for presentation at the Heads of Space Agencies Summit in Washington (January, 2014). An outline of those issues currently expected to be covered by the Team Report, together with associated recommendations that have emerged already from the study, are provided in the present paper. These items can, however, be expected to show ongoing modifications as the study progresses.