Since NASA launched MAVEN on a yearlong mission to Mars at the end of last year, the organization has been thinking about sending more people into space for longer periods of time. To prep for these kinds of missions, NASA asked the Institute of Medicine, the health division of the National Academy of Sciences, to come up with ethics standards it can use to decide if long-term missions can be carried out even if they go against current health standards.

NASA's most recent health standards divide missions into five tiers of risk and outline how it will help astronauts before, during, and after those missions. But the organization knows some missions that send astronauts into space for years at a time — like a proposed three-year-long trip to Mars — won't fit into any of those divisions. The Institute of Medicine designed basically a three-step process for accepting those missions: first, NASA has to decide if the mission meets current health standards. If it doesn't, NASA has to deem the mission ethically acceptable and an exception to the rules. In that case, NASA then has to carefully choose and train each participating astronaut and crew member for the upcoming years of work.

Do the risks outweigh the benefits?

Extensive prep for space travel isn't new for NASA or other competing space programs. NASA astronauts already have to complete over 300 hours of training in shuttle simulators before they go into space, and Russian space crews have spent 105 days inside sealed tubes to mimic living in a space shuttle before actually launching on a mission. These new standards focus more on NASA and its thought process before a mission even gets started. One of the biggest points made in the report regards the benefits a mission will have for society at large — NASA will have to prove that sending a team of astronauts into space for years at a time will yield significant scientific discoveries that will push society forward.

One of the ethics principles proposed also appears to allude to an astronaut's choice to participate in certain missions: it states that "NASA should ensure that astronauts are able to exercise voluntariness to the extent possible in personal decision-making regarding participation in proposed missions." In addition to monitoring astronauts' health throughout the mission, NASA also has to update them on potential health risks leading up to a mission and allow them to decide if they want to participate despite those risks. It seems unlikely that an astronaut would refuse a space mission after going through NASA's rigorous selection process and extensive training, but as astronauts could be more selective when missions have seriously potential health risks, these guidelines could make NASA more selective as they choose space missions that take up a large portion of an astronaut's life.