As NASA plans to send astronauts to an asteroid or even to Mars in the coming decades -- missions that could last well beyond 30 days -- they're grappling with an ethical dilemma. How do they handle decisions on long-distance space exploration when it could expose astronauts to high or unknown health hazards?
To help develop an ethical framework for venturing into this unknown territory, the space agency asked the Institute of Medicine to convene a panel of experts to offer some helpful guidelines. The results in a 187-page report were released Wednesday.
"Long duration and exploration spaceflights (including extended stays on the ISS or exploration missions to an asteroid or Mars) will likely expose crews to levels of known risks beyond those allowed by current health standards," according to the report led by Jeffrey Kahn of the Johns Hopkins Berman Institute of Bioethics, "as well as to a wide range of risks that are poorly characterized, uncertain, and perhaps unforeseeable."
The risks include radiation-induced cancers; loss of bone mass from long stints in zero gravity; nausea or fatigue from extreme radiation if astronauts get hit by a solar storm; and blurred vision. That's just a short list of the health hazards that researchers are aware of. It's also not counting the long-term psychological toll that dealing with stressful situations in a confined enclosure can take.
Among the report's recommendations: Avoid harm by minimizing risk to astronauts. Missions should be valued for the benefits they provide. Make sure the benefits outweigh the risks enough for the mission to be worthwhile. Operate in a transparent and accountable way, and keep astronauts informed of the risks they face. Basically: Act in a responsible and transparent manner.
As it stands, any sort of long-term exposure could very well take astronauts past the current safe limits for exposure, which puts NASA in something of a bind. A study that tracked the Curiosity rover's radiation exposure on its way to Mars found that the round-trip journey could potentially exceed the currently acceptable limits for astronauts. Scientists may have to figure out how to make the trip shorter, the spacecraft more protective – or, as one scientist put it, consider "reassessing what level of risk we think is acceptable."
So what does NASA do? Relax the current standards? Make a looser set of exposure standards for long-distance space hangs? No go, the IOM report said.
"The committee finds relaxing (or liberalizing) current health standards to allow for specific long duration and exploration missions to be ethically unacceptable," they wrote.
The only way to allow for such missions ethically is to grant an exception to the rule on a case-by-case level, they said.
"Exceptions to health standards should be considered on a mission-by-mission basis, used in very limited circumstances, and following the ethics framework recommended," the study authors wrote.
Among its other considerations, the agency should also offer lifetime healthcare for its astronauts, the experts concluded. They also have to take into account that there may be different risk profiles depending on the astronaut. And they have to constantly monitor the astronauts and collect as much health data as they can while also protecting the spacefarers' privacy.
In spaceflight, there always has been and will continue to be significant risk, the authors pointed out.
"From its inception, human spaceflight has pushed the boundaries of acceptable health and safety risks for astronauts," the study authors wrote.