It’s a classic superhero tale: Inconspicuous, underestimated, our hero is revealed to have powers beyond imagination! The hottest and coldest environments on Earth, decades without water, the powerful radiation of space – none of it is any match for…the tardigrade!
This chubby, microscopic, eight-legged animal may be an unlikely hero, but tardigrades, also known as water bears due to their shape under a microscope, possess superpowers when it comes to surviving really harsh conditions. Understanding how they tolerate extreme environments – including the one astronauts experience in space, with microgravity and elevated radiation levels – can better guide research into protecting humans from the stresses of long-duration space travel. An experiment starting aboard the International Space Station, called Cell Science-04, will help reveal how tardigrades do it.
“We want to see what ‘tricks’ they use to survive when they arrive in space, and, over time, what tricks their offspring are using,” said Thomas Boothby, assistant professor at the University of Wyoming in Laramie and principal investigator of the experiment. “Are they the same or do they change across generations? We just don’t know what to expect.”
One option in the tardigrade bag of tricks could be producing tons more antioxidants to combat harmful changes in the body caused by increased radiation exposure in space.
“We have seen them do this in response to radiation on Earth,” said Boothby, “and we think the ways tardigrades have evolved to withstand extreme environments on this planet may also be what protects them against the stresses of spaceflight.”
The research team will look at what happens with tardigrade genes in space. Knowing which ones are turned on or off in response to short-term and long-term spaceflight will help researchers identify specific ways tardigrades use to survive in this stressful environment. If one solution they have is to turn up the dial on antioxidant production, for example, genes involved in that process should be affected.
Checking which genes are also activated or deactivated by other stresses will help pinpoint the genes that respond exclusively to spaceflight. Cell Science-04 will then test which are truly required for tardigrade adaptation and survival in this high-stress environment.
Data from the space station experiment will also offer a comparison for Earth-based research. The latter is more common and less costly, and uses simulated spaceflight conditions to study tardigrade responses. The current experiment will tell researchers how similar those conditions are to actual spaceflight.
The tiny heroes of Cell Science-04 won’t be the first spacefaring tardigrades to join an astronaut crew. They have already been shown to survive even the vacuum of space when exposed outside the space station for an experiment. This time, they’ll be on board living and reproducing inside special science hardware developed for the station by NASA’s Ames Research Center in California’s Silicon Valley, which also manages the mission. Called the Bioculture System, the hardware lets scientists carry out long-term studies of cultures of cells, tissues, and microscopic animals in space by allowing real-time, remote monitoring, and finer control over the conditions in which they grow.
In the long run, revealing what makes tardigrades so tolerant could lead to ways of protecting biological material, such as food and medicine from extreme temperatures, drying out, and radiation exposure, which will be invaluable for long-duration, deep-space exploration missions. That’s superhero-size potential for the teeny tardigrade.
Boothby’s research is supported by NASA’s Biological and Physical Sciences Division.