Does life in space affect your gut bacteria? Twenty mice traveling to the International Space Station will find out. Early Friday morning, SpaceX plans to launch its 15th replenishment mission from Cape Canaveral and send its Dragon spacecraft, loaded with nearly 6,000 pounds of cargo, into orbit. Most of this will be a scientific payload – tools and equipment to help the six crewmembers do some science on board.
One of these experiments will involve stinging, weighing and collecting faeces from the new mouse arrivals. Oh, and film them during sleep.
Rodents are part of a study that examines how life on a sterile ship changes the circadian rhythm in the dark vacuum of space – potentially destroying a healthy microbiome. It is a mouse mirror of the double experiment of astronaut Scott Kelly. Because before NASA can start sending people to Mars, they want to know exactly how the long journey is related to their bodies, including their entire resident bacteria.
Ten of the mice will spend 90 days in space (that's about nine years) in Homo sapiens time). "We're trying to understand the cascade of events that happens when microgravity interrupts sleep and wake cycles," says Martha Vitatterna, a co-principal investigator of the study and deputy director of the Center for Sleep and Circadian Biology at Northwestern University. Microbes make all kinds of essential molecules that humans and mice themselves can not produce; Vitaterna and her colleagues hope to find out if shifts to these chemical signals affect their host's ability to survive things like sleep loss that can upset their metabolism and immune systems.
Your team sends two different mouse strains into space, one that they expect to slumber exactly at zero G, and one that was a light sleep in simulation experiments. Thanks to their genes, poor-sleep mice do not produce melatonin.
The Earthbound twins of both tribes will be housed in one of NASA's research facilities, in identical habitats as those aboard the ISS – a sealed metal box with air-blocking portholes and a sleek air filtration system. You will be exposed to exactly the same environment as gas composition, temperature and lighting to simulate day and night – but with a delay of three days. A data stream for the ISS will show scientists on the ground how to replicate the minute-long conditions on the space station.
The project is analogous to NASA's Year in Space study, in which astronaut Scott Kelly spent 340 days intensively observing aboard the ISS while his identical twin brother Mark (a retired NASA astronaut) took the same steps on planet Earth lay back. Northwestern was one of 10 research teams from around the country who teamed to find out how space changed Scott's body.
Vitaterna's team discovered that weightlessness changed the balance between the two dominant bacterial groups in Scott Kelly's gastrointestinal tract, but things returned to normal once he returned to Earth. Spacecraft must be kept extremely clean to protect astronauts from dangerous pathogens, and scientists have wondered if the lack of vermin could make it difficult to replenish a diverse microbiome. But overall, the scientists were surprised at how little the entire variety of his gut microbes changed in his space year.
To understand this, there is also a much larger NASA study – the Astronaut Microbiome Project – which seeks to track bacterial communities in the bodies of ISS crew members before, during and after their missions. The space agency began in 2013 to collect blood, spit and smears (from foreheads, underarms and yes, stumbling) from astronauts and collected the last round last February. The results, which have not yet been published, will provide the best insight into the effects of space on body bugs, including effects on metabolism and immune function.
You can dab people to their heart's content, but you you can not dissect it. Where do the planned rodent studies come into play? After their journey, scientists will look into various organs such as the liver and spleen to better understand the links between inflammation, altered metabolism, and changes in the microbiome. All this information will be important to the development of Mars missions that keep the astronauts' internal engines running.
If everything goes according to plan, the mice will arrive on Monday, July 2, along with a grinning, floating companion robot and space station special tiny aquariums to breed microscopic chemical gardens in Zero-G. It's just another productive day of experiencing aboard the good ship ISS.