Gun Testing Conducted by Experts to Check if Space Impact Can Kill Tardigrades

Tardigrades are one of the world's most unique and less understood organisms. One thing it's known for is its apparent indestructibility that has inspired various cameos in sci-fi films. What we can add to its impressive list of abilities is to be fired out of a gun at top speeds.

Scientists, for a good cause, shot tardigrades out of a gun to know whether tardigrade-like organisms could be able to survive conditions in space. This knowledge will allow researchers to place constraints on how and where we may find space organisms within our solar system and, most importantly, how to avoid contamination.

Tardigrades Explained

Tardigrades or "water bears" are scientifically known as Tardigrada, and are omnivorous microscopic egg-legged animals. According to National Geographic, tardigrades are believed to be able to survive the vacuum of space and an apocalypse while looking like adorable microscopic bears.

There are roughly 1,300 species of tardigrades in the world and are considered aquatic animals. This is because of the thin layer of water necessary around their bodies to prevent dehydration.

Tardigrades have been found in various environments from deep-sea trenches to sand dunes. On the other hand, lichens and freshwater mosses are their most preferred habitat which led to their nickname: the moss piglet.

Despite their squishy appearance, tardigrades are actually covered by a touch cuticle similar to insects exoskeletons sported by praying mantises and grasshoppers that they are related to. Like most insects, moss piglets have to shed their cuticles in order to grow and use their six claws on each of their 4 feet to cling to plant matter.

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Indestructible Tardigrades

It's no secret that tardigrades are virtually indestructible. In 2019, a lunar lander carrying tardigrades crashed on the surface of the moon. And though it would normally instantly kill any creature on Earth, experts believe that the tardigrade is still surviving up to today.

Such characteristics led scientists to question how violent an impact can the water bears survive? Hence, Alejandra Traspas and Mark Burchell astrochemists and astrophysicists from the University of Kent, UK designed an experiment to test out the tardigrade's well-known indestructibility.

A study published in the journal Astrobiology, entitled "Tardigrade Survival Limits in High-Speed Impacts-Implications for Panspermia and Collection of Samples from Plumes Emitted by Ice Worlds" used a two-stage-light-gas-gun that accelerated projectiles via gunpowder and light gasses like helium and hydrogen to achieve top speeds of 8 kilometers per second.

Researchers loaded individuals of the Hypsibius dujardini species of tardigrades into nylon sabots that were frozen to induce hibernation. The sabots were then loaded in the gun and fired at sat targets at 0.556 to 1 kilometer per second in a vacuum chamber.

All tardigrades recovered after roughly 8-9 hours. The impacted tardigrades also survived up to an impact velocity of 825 meters per second but took longer to recover. This suggests that the impact velocity survivability threshold of the tardigrades is between 825-901 meters per second.