Axiom 4 mission: What are tardigrades and why Indian astronaut Shubhanshu Shukla is carrying them with him to space?

Indian astronaut Shubhanshu Shukla is all set for his two-week journey to the International Space Station (ISS) under the Axiom 4 mission. He will undertake some of the experiments for ISRO along with three other astronauts in his 14-day time in space. One of the most intriguing experiments, known as the Voyager Targdigrades mission, aims to explore how these microscopic creatures survive, reproduce and repair themselves in the harsh environment of space. Besides observing resilient lifeforms, the experiment’s objective is to prepare for the future of human space exploration. If tardigrades thrive in hostile environments, it can revolutionise space medicine, biomaterials and cryopreservation. 

What are Tardigrades?

Tardigrades, also known as water bears, are strong aquatic creatures that existed for about 600 million years, surviving Earth’s mass extinction events. Tiny around 0.5mm long, these eight-legged organisms have a claw-like structure and a mouth specialised for extracting nutrients from plant cells, algae and tiny invertebrates. These organisms thrive in extreme environments and weather conditions. They are most commonly found in the thin films of moisture on mosses and lichens, and are also known as ‘moss piglets’.

In recent decades, Tardigrades, first discovered in 1773 by German zoologist Johann August Ephraim Goeze, has gained traction among scientists. Their resilience to extreme conditions surviving temperatures from -272.95°C to 150°C,  their survival mechanism, makes tardigrades special. They owe their survival skills to a biological process known as cryptobiosis.

Why Tardigrades are taken to space? 

In the Voyager Tardigrades experiment, these eight-legged organisms will be sent to the ISS in their dormant tun state. Scientists will rehydrate and revive them to study how space radiation and microgravity affect their biology, once they are in orbit. The main objective lies in identifying genes and molecular mechanisms which are responsible for tardigrades’ DNA repairing and maintaining function in space. The insights can be helpful for protecting astronauts from radiation during long-duration missions. It also prevents muscle and bone loss in zero gravity. In addition, it can preserve biological materials during extended space travel.

Meanwhile, this is not the first time, Tardigrades are taken to space, nearly 3,000 tardigrades were sent to space aboard the European Space Agency's Foton-M3 mission in 2007. In the experiment, many survived and some even reproduced after returning to Earth.