Tardigrades: Survive The Vacuum Of Space

When it comes to surviving in harsh environments, perhaps no known living organism is as durable as the tiny tardigrade. Although the largest adults of this fascinating species grows to only 1.5 millimetres in length, they have an almost magical ability to withstand harsh environments that would easily kill nearly any other animal.

Tardigrades have survived temperatures close to absolute zero (-459 degrees Farenheit) as well as temperatures well above the boiling point of water (304 degrees Farenheit). They have survived UV radiation exposure 1000 times stronger than that found on the earth’s surface and atmospheric pressure nearly 6 times greater than that found on the deepest point of the ocean floor. Tardigrades have also been known to survive almost 10 years without any water.

Perhaps most incredibly, tardigrades have managed to survive the harsh vacuum of outer space for multiple days (Reference DOI). This was demonstrated in 2007 when researchers aboard the FOTON-M3 spacecraft released tardigrades into the vacuum of space in low orbit. Incredibly, most of the tardigrades exposed to the vacuum of space managed to survive the extreme cold, deadly levels of radiation, and lack of oxygen, pressure, and moisture.

What Is A Tardigrade?

The tardigrade – also known as the waterbear because of its slow, bear-like gait – is a family of tiny, segmented animals with 8 legs. Adult tardigrades usually average approximately 1 mm in length. There have been over 1150 new species of tardigrades identified since their initial discovery in 1773.
When they’re not being blasted into outer space, these little creatures inhabit every realm of the earth. From the Himalayan mountain range, down to 13,000 feet below the sea, from the polar ice caps to the insides of boiling hot springs. But despite their extreme durability, tardigrades are most commonly found in moist, nurturing environments. They’re most often found in lakes, meadows, and lichen.

How Does The Tardigrade Do It?

While scientists still have much to learn about the tardigrade’s ability to endure incredibly harsh envrionments, it appears that these tiny 8 legged creatures have the ability to temporarily suspend all biological function when faced with dehydration. The tardigrade’s body has the ability to halt its metabolism and maintain the structure of their cells in a death-like state, known as cryptobiosis. In this state, a dehydrated tardigrade can survive with a water content 1% of their normal levels, with their metabolism functioning at .01% of its usual state.

It is this near death state that allows tardigrades to survive days at -328 degrees farenheit, or minutes at a mere 1 degree above absolute zero. It is this state that also allows tardigrades to survive the low pressure vacuum of outer space, as well as extremely high pressure environments – some tardigrades have been known to survive pressure equal to 6,000 atmospheres. This is almost 6 times the water pressure of the Mariana trench – the deepest point of the earth’s oceans.

Perhaps most puzzling however, is how the tardigrade manages to endure the deadly UV radiation of outer space – 1000 times the levels of UV radiation found on earth – without suffering damage to their DNA. UV radiation not only causes severe damage to biological tissue (as evidenced by sunburns) and genetic damage to cells (as evidenced by skin cancer), but at the incredibly high levels of radiation found in outer space, UV radiation is also known to be sterilizing.

Researchers have theorized that the high levels of radiation exposure likely damaged the surviving tardigrade’s DNA, but that these creatures may have a mechanism to repair any such damage. Understanding how tardigrades can manage this feat may unlock important secrets that have profound effects on medical research into cancer, radiation treatments, and genetics.

Zombies are looking pretty good right about now aren't they?