Tardigrades are among the most fascinating creatures encountered by zoology students. If you magnify them 10 – 30 times, they look like something concocted in the imagination of Gene Roddenberry. Resembling a cross between a bear and an insect, it seems befitting that this strange little animal would turn out to be one of the few organisms on Earth that can actually survive the harsh environment of space.
Although you’ve probably never heard of them, tardigrades are actually all around us. If you’ve ever seen moss growing on a tree or lichen on the side of a concrete building, you were probably looking at tardigrades without even realizing it. In fact, these little creatures can also be found living in the dirt on the bottom of you shoes, especially if you happen to have walked through the forest recently.
Scientists classify tardigrades as micrometazoans which means they are really small animals where every individual of the same species has exactly the same number of cells. If this isn’t odd enough, these incredible little creatures can survive for long periods of time in a completely dehydrated state. Then, if you place their little dessicated bodies in water, they will reconstitute and swell up into a barrel shaped body with four pairs of short fat appendages protruding out. In this state, they are barely discernible as a little speck to the human eye. However, if you view them under the scope in this state, you can watch their movement as they lumber along like a miniature space alien bear. Most people who are lucky enough to have seen a tardigrade under the scope never forget it.
In 2007, tardigrades became famous for being one of the first creatures sent into space in a way that they would actually be exposed to space conditions, not protected like the astronaunts and other animals that have gone into space. Funded by the European Space Agency (ESA), an experiment was conducted where one group of tardigrades were exposed to space vacuum and another group was exposed to both space vacuum and solar radiation. Both groups of tardigrades were in their dessicated state when they were sent in to space. Both groups were thoroughly analyzed for survival and for defects after they returned.
In 2008, the results of this remarkable experiment were published in a peer reviewed scientific journal called “Current Biology.” It was reported that almost all of the tardigrades exposed to space vacuum survived and that some of the tardigrades exposed to both space vacuum and solar radiation survived which is extraordinary to say the least.
These results were heralded by the scientific community and the world at large as quite remarkable. However, it is no accident that tardigrades were selected for this space experiment. Scientists have long surmised that tardigrades may be capable of surviving the harsh conditions of space because their remarkable ability to survive in a completely dehydrated state. It is now thought that tardigrades serve as an excellent model to figure out how living tissue can survive in space. Additionally, they seem to have won the heart and soul of the news media reporting on this story.