Tardigrades
Context: Scientists study tardigrades for their extreme survival abilities, with space experiments like Voyager Tardigrades aiming to unlock advances in biology, medicine, and space travel.
Important Pointers:
What are Tardigrades?: Tardigrades, also known as water bears or moss piglets, are microscopic invertebrates from the phylum Tardigrada, with about 1,300 known species worldwide.
Habitat and Distribution: Tardigrades are aquatic micro-animals requiring a thin film of water, found in diverse ecosystems—from deep seas to sand dunes, and thrive in mosses and lichens.
Discovery and Evolutionary History: Discovered in 1773 by Johann August Ephraim Goeze, they have existed for over 600 million years and survived all five mass extinction events.
Physical Structure: About 0.5 mm long, they have four pairs of legs with claws, and a piercing-sucking mouthpart for feeding on plant cells, algae, and micro-animals.
Survival Capabilities: Tardigrades endure extreme conditions—temperatures from –272.95°C to 150°C, 40,000 kPa pressure, space radiation, and even 30 years of freezing.
Mechanism of Resilience: They survive via cryptobiosis and anhydrobiosis, entering a tun state where their metabolism drops to <0.01% and water content reduces by >95%.
Protective Proteins: Tardigrades produce CAHS proteins which form a vitrified gel, protecting their cellular components from heat, radiation, and vacuum.
First Space Mission (2007): About 3,000 tardigrades travelled in ESA’s Foton-M3 mission, survived direct space exposure, and some even reproduced successfully.
Voyager Tardigrades Experiment (2025): The experiment aboard the ISS aims to study the revival, survival, and reproduction of tardigrades under space radiation and microgravity.
Scientific and Space Applications: The goal is to identify resilience genes for potential use in protecting astronauts, developing stress-tolerant crops, and organ preservation.