Keywords:
Experimental, Radioprotection / Radiation dose, Dosimetry, Biological effects
Authors:
T. Squire; ACT/AU
DOI:
10.26044/ranzcr2019/R-0012
Purpose
Only 24 humans have ventured beyond Earth's protective magnetosphere, briefly during the Apollo missions to the Moon. Deep space radiation exposure has a high liklihood of significant biological consequence to astronauts when they explore deep space beyond the magnetosphere such as during a mission to Mars Fig. 1.
Human hibernation is not a new concept, with 1950s scientific literature and movies demonstrating its potential use for deep space travel. Synthetic hibernation known as “torpor” would improve the amount of supplies required and therefore lessen fuel required for missions to Mars and beyond1 Fig. 2.
Evidence suggests that animals when hibernating demonstrate relative radioprotection compared to their awake state. Hypothermia and sleep also appear to be radioprotective2,3. Circadian rhythm disrupted cells also appear to be more susceptible to radiation damage4. This is particularly important for astronauts who lack regular day/night lighting conditions and meal times. A synthetic torpor state for astronauts on deep space missions may provide a biological radioresistant state due to decreased metabolism and an enforced circadian rhythm when lighting schedules and feeding times are regulated.
We investigated which biological factors potentially contribute to radioprotection during human torpor on deep space missions.
The A.L.A.R.A. radiation protection concept defines time, distance and shielding as ways to decrease radiation exposure. Whilst distance cannot be altered in space and shielding either passively or actively may be beneficial, time of exposure during transit may be drastically decreased with future propulsion systems.
We estimated radiation dose received by astronauts during a transit to Mars with chemical, nuclear and electrical propulsion systems.