NASA’s Human Research Program (HRP) has released a new report that suggests storing pharmaceuticals at cryogenic temperatures on deep space missions, including proposed expeditions to Mars. At issue is both prolonged exposure to radiation and mission lengths that extend well beyond a product’s shelf life.

Pharmaceuticals stored aboard the International Space Station (ISS), for example, have a shorter shelf-life than those stored terrestrially, according to a retrospective study that compared control samples to four payloads returned from ISS after durations ranging from 13 to 880 days. The study looked at 33 products, of which 22 were solid, seven semisolid and four liquid. In each test, samples from the payload showed increased physical changes and reductions in chemical potency.

“In the context of a Mars mission,” the report says, “it should be noted that the pharmaceuticals … were stored on ISS, an environment within the Earth’s magnetic field. On a deep space mission, outside of the Earth’s magnetic field, degradation is likely to be more rapid varying with the stage of the solar cycle.”

HRP analysts suggest multiple long exposure studies in a deep space environment removed from Earth’s magnetic field in order to better understand this degradation.

Radiation also plays a role and is believed to be as much as five times more severe in deep space than in low Earth orbit. The report suggests cooling samples to between 100 and 50K and thereafter exposing them to energetic protons created with a beamline. Post analysis would thereafter determine levels of degradation and the feasibility of using cryogenic storage.

“One could envision a cache of pharmaceuticals purposely delivered and stored cryogenically on the Martian surface prior to astronaut departure from Earth, and upon arrival, the pharmaceuticals could be reconstituted or warmed to room temperature for use, as needed,” says the report.