Implications of Radiation Risk for Astronauts

Sneha Shirsat shares her ethics & society case study, which she completed as part of our Young Scientist Program.

Humankind is on a fast track to venture out into horizons of the universe. The concept of space missions creates a picture of extraterrestrial travel, trips to Mars and even beyond our solar system. It is important that these technological advances have some ethics embedded in them. Along with factors like duration of space travel, accompanying resources and fuel consumption, it is crucial to consider the radiation exposure encountered in the mission. Two major types of radiation in space are galactic cosmic radiation (GCR) and solar energetic particles [1]. The GCR can be considered as nuclei of elements travelling at nearly the speed of light which are highly permeable. Hence, for space missions this radiation is a main concern for two reasons: it is ionizing and difficult to shield from. It would not just penetrate deep into the human body but would cause water to ionize inside the body and severely damage health in a long term perspective [2]. Along with this known threats to astronaut health include bone loss, retinal and hallucination flashes, nausea, and other effects. [3].

Given these facts and figures, it is known that astronauts indeed risk their lives for space missions with a positive intent of contribution to science, technology and, in turn, humanity. As we make progress in increasing the protection of space suits, it is important to consider the present situation. For a medicine to be made available to everyone, it undergoes a series of rigorous tests, on animals, on cells, etc. Now let’s put this in the context of astronauts. The present generation of astronauts would face more dangers than the next one. Collecting data from present missions and analyzing effects on them would eventually help technologists offer a better shielding for the next batch of astronauts. This makes the present generation astronauts the ‘guinea pigs’ of space flight missions. Understanding that these missions are ultimately morally important, such experiments on astronauts are acceptable. It is important to consider how much sacrifice is acceptable or is even actually required to achieve our goal of exploration.

For one way trips to another place, say for instance Mars, a 180-day trip equals to a dose of roughly one Sievert, ~700 millisievert, and a stay on the planet would account for even more factors. The amount radiation trapped in the planet’s atmosphere, solar particle events would account for 0.67 millisievert per day [4]. An exposure of 1 Sievert accounts for a 5% increase in fatal cancer risk. This spurs two lines of thought, despite being aware of this risk of sending humans and making the humans survive with an already deteriorated health. Consequences would mean having an unhealthy human species surviving in an unknowingly dangerous environment. In a very long-term perspective, the offspring of unhealthy humans would mean a vulnerable human species colonizing the planet. As humans, if we really need to find a second home, how moral is it to proliferate this new home with relatively damaged species?

Concern regarding radiation doses for astronauts is specific but not limited to humans alone. In addition to this, long-term missions might eventually lead to terraforming of the planet. Things that would be on board would comprise of food, animals (whether live or embryos), plants (saplings or seeds). It is important to understand that any living being in a space mission is an astronaut. If we dream of a second home, the components that make build it are equally important. We think of making an alien world ‘human livable,’ but we often tend to forget the blocks which make them so. Humans would not survive on Earth itself if our animal/plant kingdom gets disturbed, so how do we plan to live (rather than simply survive) on a planet without them? And how much are we concerned about it at the moment? It is very critical to have a balanced outlook of ‘life’ on other planets and not humans alone. Equal attention to microbes, plants, and animals on-board should be given to build radiation safe ecological support systems for them.

This also raises an issue regarding the agreements in missions like Mars One, where people from non-scientific or non-technological backgrounds have enthusiastically volunteered for the progress of science. Are they fully aware of the radiation risks? It is important to have a personalized set of threats for each individual sent for such mission. Every human is unique and can face unique set of health issues. While it is totally rational to generalize the threats for all volunteers, would it not be more ethical to provide a personalized threat report so that the individual can completely understand the threats and is fully aware of it? With their bravery and determined enthusiasm to serve their lives as an experiment, is it not their right to be fully aware of the cost at which they are doing this? Why not anonymously make the data available to doctors and scientists from the world who can reflect on different aspects and suggest medicinal options for a relatively better health of the astronaut? Is it not our responsibility to at least reduce a great amount of danger given the fact that we are truly aware of?