Context:

Astronaut Shubhanshu Shukla will conduct an experiment on the International Space Station (ISS) to study tardigrades in space.

Objectives of the experiment include:

• Mapping the DNA repair pathways of tardigrades in space
• Understanding their reproductive capacity in zero gravity
• Identifying genetic markers for resilience
• Informing strategies to protect astronauts on long missions
• Helping develop technologies to preserve human tissues and organs

The experiment could also influence terrestrial applications, such as engineering crops that withstand extreme climates or developing better biopreservation methods.

What Are Tardigrades?

• Tardigrades are tiny aquatic animals, typically just 0.5 mm in length, with four pairs of stubby legs tipped with claws. Despite their minuscule size, these creatures are biological powerhouses.
• Fossil evidence suggests tardigrades have existed for around 600 million years, predating the dinosaurs by about 400 million years. Remarkably, they have survived all five major mass extinctions, and scientists believe they may persist long after humans are gone.
• Tardigrades live in a wide range of environments — from ocean trenches and high mountains to the thin film of moisture on mosses and lichens, which gives them the nickname moss piglets.
• Their ability to thrive in such diverse and often hostile environments is what makes them a focus of cutting-edge scientific research.

Why Are Tardigrades Studied in Space?

• Since their discovery in 1773 by German zoologist Johann August Ephraim Goeze, tardigrades remained largely a curiosity until recent decades, when researchers began to uncover their astonishing resilience.
• Tardigrades first ventured beyond Earth in 2007, when about 3,000 specimens traveled aboard the European Space Agency’s Foton-M3 mission. They were exposed to space in a dehydrated tun state. Upon returning to Earth and being rehydrated, researchers found that many survived — and some even reproduced.
• Although UV radiation in space caused some damage, the experiment confirmed that the vacuum of space itself is not fatal to these organisms. This landmark discovery made tardigrades the first animals known to survive direct exposure to outer space.

What makes Tardigrades So Resilient?

• The secret lies in their ability to enter cryptobiosis, a survival state where their metabolism slows to nearly zero, and they lose up to 95% of their body water — a condition known as anhydrobiosis. In this state, they form a shrunken, dehydrated structure called a tun.
• In the tun form, tardigrades produce unique proteins like cytoplasmic-abundant heat soluble (CAHS) proteins. These proteins form a protective gel-like matrix inside cells, which prevents damage from desiccation, radiation, and extreme temperature fluctuations.

Conclusion:

Studying tardigrades helps scientists answer larger existential questions. How might life survive interplanetary travel? Can humans engineer similar resilience for long-term space colonization? Could life exist elsewhere in the universe under similarly extreme conditions?