Shrimp Show Promise as Future Astronaut Food in Simulated Microgravity Study

Feeding astronauts on long-duration missions remains one of the toughest problems in space exploration, since food cannot simply be grown the same way it is on Earth. A team of researchers at Japan's Okayama University of Science has been investigating whether seafood, one of the oldest and most widely eaten foods on the planet, could realistically become part of that solution. Their new study, recently published in the journal Microgravity Science and Technology, examined how shrimp behave and feed when exposed to simulated microgravity, offering an early but promising signal that crustaceans could form part of a future food chain for astronauts living on the moon or beyond.

Why testing animals in microgravity is so difficult

Most microgravity experiments on Earth rely on drop chambers or parabolic flights, both of which only offer a few seconds of true weightlessness, far too short a window for meaningful behavioural testing. The International Space Station allows longer exposure, but access is expensive and space onboard is extremely limited. To get around this, the research team turned to a device called a clinostat, a chamber that rotates its contents to mimic some effects of microgravity by cancelling out the pull of gravity through constant repositioning. According to the study titled In Situ Observation of Shrimp Feeding Process Under Microgravity Environment, published by researcher C. Yokota and colleagues, standard clinostats typically rotate at only 10 to 25 rotations per minute, a speed too slow for agile animals, since they can simply reorient themselves before the simulated weightlessness takes effect.

Building a faster clinostat for complex animals

To solve this problem, the researchers designed a custom clinostat that spins at around 130 rotations per minute, more than twice every second. This rapid rotation does not give animals like shrimp enough time to reorient their bodies to Earth's gravity before their orientation shifts again, effectively creating a state of pseudo-weightlessness inside the chamber. According to theofficial announcement from Okayama University of Science, this was the first study of its kind to observe live shrimp feeding behaviour under simulated microgravity conditions using this kind of high-speed rotational setup.

Watching juvenile shrimp try to eat while spinning

For the main experiment, juvenile kuruma shrimp were placed inside a sample box fitted with a digital camera and light source, then subjected to fifteen minutes of simulated microgravity while researchers observed their feeding attempts. The rapid rotation caused water inside the container to slosh around with considerable force, generating an estimated internal flow of 0.15 metres per second. To cope with this turbulence, the shrimp were seen holding onto a plastic mesh net placed inside the container, and they largely ate only food pellets that drifted directly in front of their mouths rather than actively hunting as they would under normal gravity. Notably, the shrimp fed most effectively during brief moments when the water flow settled, offering a strong clue that the animals were capable of feeding in microgravity conditions when given the chance.

Genetic changes linked to movement and body structure

Beyond behaviour, the researchers also looked for biological changes at the genetic level. A separate group of shrimp was exposed to twenty-four hours of simulated microgravity, after which their RNA was compared against a control group kept under normal gravity using Gene Ontology analysis. This comparison revealed significant changes in genes linked to chitin metabolism and cuticle development, both of which are closely tied to a shrimp's exoskeleton and its ability to move. These genetic shifts suggest that microgravity affects shrimp on a biological level, not just in terms of visible movement or feeding behaviour.

Testing brine shrimp over several continuous days

Since larger shrimp are difficult to test in statistically significant numbers, the team ran a supporting experiment using Artemia, more commonly known as brine shrimp or sea monkeys, exposing them to four continuous days of rotation inside the clinostat. Throughout this longer exposure, the brine shrimp continued to successfully feed on algae, produce waste and grow noticeably in size, suggesting they were able to live largely normal lives even under sustained simulated microgravity, with no major visible ill effects recorded during the experiment.

What still needs to be studied before shrimp reach space menus

Not every part of the study went as planned. Researchers had originally hoped to gather comparable data on fish, but limitations in the camera setup meant the current results only cover shrimp and brine shrimp, leaving fish behaviour as an open question for future research. Separate ongoing efforts, including the Lunar Hatch Program, which aims to introduce fertilised fish eggs into lunar water systems, and SpaceGenFish, which is developing automated aquaculture systems for use aboard the International Space Station, are working to fill that gap. For now, the shrimp results offer an encouraging, if early, sign that seafood aquaculture could realistically play a role in feeding astronauts on future lunar bases, provided further research continues to build on these initial findings.