The researchers are from several institutions and will run their own investigations to test how spaceflight and the aging process affect certain organ systems in mammals, especially those effects that might be comparable to human diseases such as osteoporosis, muscle wasting and immune dysfunction, said principal investigator Michael Roberts, deputy chief scientist at the U.S. National Laboratory (which is also sponsoring the investigation).
"These research questions will be addressed by observing the activity levels of the younger and older mice and different measures of activity and function in their genes and major organ systems," he said in an e-mail to Seeker.
While mice and rats are not human subjects, Roberts says they are good models for probing the effects of spaceflight on mammalian systems – such as cardiovascular or reproductive systems – that humans share. Rodents are also prone to many human-type diseases, including diabetes, osteoporosis and even cancer. Another advantage of rodents is they have shorter lifespans and breed more quickly than humans, allowing researchers to quickly see the effects of aging in a single generation exposed to microgravity for a few weeks.
"Our mission at the ISS National Lab is to enable research in space that benefits Earth. The NASA Human Research Program has the mission to identify and mitigate risks to astronauts. This experiment directly addresses both missions by seeking to improve our understanding of the effects of spaceflight on human physiology using an animal model, to reveal how these effects may be exacerbated or attenuated by age and how faithfully these molecular and physiological changes mimic disease," Roberts said.
"The data collected will be used to inform those of us on Earth about new, early-stage biomarkers of disease. For those working in space, these biomarkers will be used to inform physicians and engineers about effectiveness of current and planned countermeasures to combat physiological changes associated with extended spaceflight," he added.
Waiting for results will still take a while, because analyses on the data take at least a year or more to perform after the mice and associated biospecimens (such as blood samples) return to Earth. It's not as though mice can easily catch a ride home; they have to wait for a SpaceX Dragon spacecraft to come to the station, which only happens a few times a year at best.
Future rodent missions may focus on the effects of spaceflight on males and females, and how their sex alters disease onset and progression, Roberts said.
You can read more about the experiment at this NASA web page.