Imagine: You're a crew member aboard the first manned mission to Mars, months into transit to the Red Planet. You get a horrid headache, hindering your duties on the spaceship. What do you do? Well, you do the responsible thing and consult a fellow astronaut. Quick fix: she suggests you swallow a couple of painkillers.

Worse than that; what if you cut yourself while carrying out an experiment? Your wound becomes infected and you start to feel sick. The ship's doctor puts you on a course of antibiotics.

Despite the painkillers or antibiotics, your condition doesn't improve, resulting (at best) in prolonged bed rest, or (at worst) death. The nearest hospital, after all, is 50 million miles away.

What went wrong? The drugs didn't work.

This is a rather dramatized version of a recent finding by NASA-funded research: medicines appear to degrade rapidly when stored in space, putting a huge question mark over long-term astronaut health care.

For the experiment, project leader Brian Du, of the Wyle Engineering Group and colleagues from the University of Texas, Universities Space Research Association and NASA Johnson Space Center, sent four medical kits to the International Space Station (ISS), pictured below.

Each kit was identical, containing medicines commonly used by astronauts in space. Another four identical kits were stored at NASA Johnson Space Center to act as the control.

The ISS medical kits were flown in space for different time intervals ranging from 13 days to 28 months.

The study, published in the AAPS Journal, concluded that “the number of medications failing API [active pharmaceutical content] requirement increased as a function of time in space, independent of expiration date." In short, the longer the medication spent in space, the less effective it became. It degraded far quicker than the control medicines left on the ground.

So what causes the shelf-life of drugs to shorten while in space? The authors of the study point to repackaging of drugs during pre-flight that could cause issues with humidity and oxygen variations (increasing the effect of oxidation). But by far the biggest impact is most likely the higher-than-normal radiation levels in orbit when compared to the ground.

Although human space flight is suffering more than its fair share of jitters, eventually we will see astronauts venturing into deep space. Obviously, to ensure mission success, a huge amount of research will need to go into the effects of prolonged human exposure to microgravity and high-radiation environments. Likewise, as this study shows, we can't take modern medicine for granted; it is as vulnerable to the ravages of space as the men and women it is designed to protect and cure.

As per the study's abstract, more work is inevitably needed to see how various drugs degrade in space:

“Characterization of degradation profiles of unstable formulations and identification of chemical attributes of stability in space analog environments on Earth will facilitate development of space-hardy medications." —

On that note, I'll let the legendary Richard Ashcroft sing us out: