If We're Going to Become Interstellar Explorers, We Have to Find Out Why Our Immune Systems Don't Work in Space

It seems more likely than ever that humans may someday travel to alien worlds. A Dutch company held an international competition last year to send four people on a one-way trip to Mars in the hopes of establishing a permanent human colony on the red planet.  And last week, NASA successfully completed the first test of its Orion space capsule, which the agency says may one day carry up to six astronauts into deep space.

Even greater interstellar ambitions exist in fiction. Christopher Nolan’s latest blockbuster Interstellar explores the possibility that humans will someday abandon earth in search of a new home. 

Yet besides the logistical challenges of such a journey, there is also reason to believe that a prolonged expedition in space could have devastating impacts on the human immune system. Astronauts who have spent long periods of time in space have returned with weakened white blood cells, which means that if humans ever attempt to colonize another world, they better not bring the flu with them.

To better understand this phenomenon, researchers from the European Space Agency (ESA) will undertake two studies on the International Space Station in the next several months aimed at understanding the effects of microgravity on the white blood cells of rats and mussels.

Previous studies have shown that microgravity, as it exists in space, causes changes in immune system cells. However, the data from the studies is limited because the conditions created by the experiments were either artificial or lasted for a short time. By conducting the experiments in space, researchers will be able to expose the subjects to microgravity for a prolonged period and be able to test whether the higher radiation levels in space also contribute to a weakened immune system.

The rats and mussels will be exposed to a safe bacteria substitute that is created from yeast, which will determine whether the white blood cells are working normally to eliminate the invaders. White blood cells are the first line of defense against disease and understanding their behavior in space is crucial to making extended space travel possible.

The mussels and rats are considered model organisms for study because their characteristics are easy to control and examine in a laboratory. Also, mussels have very primitive immune systems, which researchers say will make them a good comparison to rats and humans.

The experiments in space will be compared to similar work conducted on the ground in order to determine whether microgravity and the cosmic radiation in space, which cannot be replicated on earth, work together to weaken the immune system.

By conducting these experiments, the ESA hopes to “help scientists develop ways to manage or prevent microgravity-induced changes in immune system function or, simply put, make these tiny warriors space-ready.”