May 18, 2011

Tardigrades Return To Space Aboard Shuttle Endeavour

A microscopic organism called a tardigrade became the first animal to survive exposure to space when, in 2007, it was launched aboard the European Space Agency's (ESA) Foton-M3 mission, in an experiment to test their ability to survive in the oxygen-deprived space vacuum, reports BBC News.

The little critter prevailed over the sub-zero temperatures and unrelenting solar winds as well as the lack of oxygen.

Tardigrades are more commonly known by their non-scientific name, the water bear. Their stocky bodies and gait have all the hallmarks of a bear, but that's where the similarity ends. The tardigrades are less than 1mm long and are found in the world's oceans, fresh water and even on land.

Genetic studies have shown that tardigrades originally lived in fresh water environments before adapting to living on land, but mainly in moist habitats. Tardigrades earned the title "hardiest animal on Earth" after studies showed the organism was capable of shutting down all of its essential biological processes when conditions are otherwise uninhabitable.

Professor Roberto Guidetti from the University of Modena and Reggio Emilia believe the organism's ability to suspend life and withstand freezing and dehydration may explain why they can survive in space.

"Tardigrades can be found all over the world from the Arctic to the Antarctic, from high mountains to deserts, in urban areas and backyard gardens," he told BBC News. "In terrestrial environments, they always require at least a film of water surrounding their bodies to perform activities necessary for life."

But if conditions change, they are capable of entering in an extreme form of resting known as cryptobiosis. In this state, they are capable of withstanding extremely harsh environments.

On Monday's final launch of the NASA shuttle Endeavour, the tardigrade once again got a ride into space on a new mission: to help scientists understand more about how this extremely hardy organism can survive for short periods in outer space.

The tardigrade joins other organisms selected to be part of a project on extreme survival.

The mission, called Project Biokis, is sponsored by the Italian Space Agency and plans to investigate the impact of short-duration spaceflight on a number of microscopic organisms. Seven experiments will be included in the project, which will study how the effects of spaceflight affects organisms on a molecular level.

The astronauts will use molecular biology to evaluate any changes in the organisms' genetic information, and also study how cells physically adapt to extreme dehydration, caused by the vacuum of space, and damage caused by cosmic radiation.

The Tardkiss experiment, one of the planned projects of the mission, will expose colonies of tardigrade to different levels of ionizing radiation, determined using a dosimeter, at different points during the mission.

The results from the Tardkiss experiment will help researchers to determine how radiation dosage effects the way cells work.

Exposure to the conditions found in space induces rapid changes in living systems, said Guidetti.

The Tardkiss study could help researchers such as Professor Guidetti develop techniques to protect other organisms, including humans, from the extreme conditions found in space. It may also help with the future long-term goal of extending the explanation of the Solar System.


Image Caption: Water bear (tardigrade), Hypsibius dujardini, scanning electron micrograph by Bob Goldstein / Wikipedia (CC BY-SA 3.0)   


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