Humans, chimpanzees and dogs tin can live in a space environs for but a few minutes before the air in their lungs expands, gas bubbles out of their blood and the saliva in their mouths begin to boil. But more fundamental organisms such as leaner and lichen tin tolerate the absenteeism of force per unit area and searing cold. And now researchers have found that animals known as tardigrades, or water bears, tin, too.

These microscopic animals—ranging in size from 0.06-inch (1.5-millimeter) adults to 0.002-inch (0.05-millimeter) larvae—are found in lichens or mosses, in soil, on mountaintops and in the sediment on the ocean flooring at depths of xiii,000 feet (4,000 meters). Given that their mossy homes can be prone to desiccation, some species of tardigrades tin can survive equally long equally a decade without wet.

They too accept an uncanny ability to resist impairment that the dominicus's ultraviolet rays cause to humans and well-nigh other more complex animals.

So in an endeavour to exam their space grit, ecologist Ingemar Jönsson of Kristianstad University and his colleagues put two different moss-dwelling species of tardigrades—Richtersius coronifer and Milnesium tardigradum—and their eggs on the European Infinite Agency's Foton M3 mission last September. While orbiting Globe at an altitude of more than 160 miles (258 kilometers), the tardigrades were exposed to the vacuum of space for ten days. Although some of them were shielded from the sun'due south light, others were bathed in UV-A (long-wave) and UV-B (medium-wave) ultraviolet solar radiation.

"We found that both species of tardigrades survived exposure to space vacuum alone very well, with no pregnant difference in survival pattern compared to ground controls," says astrobiologist Petra Rettberg of the Institute of Aerospace Medicine in Köln–Porz, Germany, a fellow member of the research squad. "Samples exposed to the combined effect of vacuum and solar radiation had significantly reduced survival."

In fact, merely x pct of the tardigrades exposed to both vacuum and radiation recovered when returned to a h2o surround—and none of the irradiated eggs hatched—but that "still represents the offset animals that have survived simultaneous exposure," Jönsson notes. Rettberg speculates that their outer layer, known equally the cuticle, may shield them from radiation.

Much like the microbe Deinococcus radiodurans, the tardigrades must besides take some cellular machinery that repairs radiations or desiccative harm. "There is no data on what is happening in the bodies of the tardigrades when exposed to radiation," Jönsson says. "So we don't know how damaged they go and nosotros don't know to what extent they are able to repair the damage."

This proves that at least some animals can survive the rigors of infinite flight unprotected, a list that might likewise include the microscopic animals known as rotifers, nematodes (roundworms), drought-resistant insect larvae, and crustaceans like brine shrimp, according to the researchers—all of which share the tardigrades' ability to survive extreme dryness.

Only lichens, which other species of tardigrades live on, prove no harm from exposure to infinite. Perhaps such tiny animals and their plant homes are capable of spacefaring. "If sheltered from solar radiation, information technology is possible that they could survive for quite many years under infinite vacuum," Jönsson says of the h2o bears. "Only the problems connected with ejection into infinite and reentry remains," such equally the searing heat of friction as rock enters or leaves a planetary atmosphere.

Ultimately, such a trip between worlds might take millions of years. At least some of the tardigrades would be practiced for the beginning 10 days. The real problem would be finding another suitable home. "You lot take to end upward in a less hostile identify than infinite," Jönsson says, "in order to reproduce and plant a population."