A Sheep’s Guide to the Galaxy


NASA is getting a little help from some woolly friends in their efforts to send humans to Mars!

One of the major problems with having astronauts in space for weeks or months or even years at a time is the effect that microgravity—a condition where the gravitational pull is greatly reduced, like when you see people and objects floating around in a spacecraft—has on the human body. In microgravity, muscles and bones can become weaker and lose density because they don’t have to work as hard in space. In fact, in microgravity humans can lose as much as 2% of their bone density per month, which really adds up when you’re talking about a round trip expedition to Mars. So before NASA sends people out into the Solar System, they want to have a better understanding of how the voyage will effect the astronauts physically, including loss of bone density and the way bones heal. Their goal is to find ways to prevent or treat problems such as these that the astronauts may face on long trips into space.

Previously, scientists had tested the effects of microgravity on rodents through a process called “unloading,” where an external support brace surrounding the rodents’ back legs takes pressure and stress off of the bone. Unloading allows scientists to study how microgravity would effect the bone and muscle tissue without having to send the rodents into space. However, rodents are very different anatomically and physiologically from humans, so the results of these studies did not give the researchers a good model of the effect these conditions would have on astronauts. A new 3-year study led by Christian Puttlitz at Colorado State University has found a critter with bones much closer to humans…. Sheep! Using a support brace on the sheep’s hind legs for intervals of 8 weeks proved to be a very close model of the effects of low gravity on human bones. They were able to show that these conditions not only severely reduced bone density, but also impaired the bone’s ability to heal itself in the event of a fracture or break. Although this is not good news, now that NASA has a better model for studying these conditions, they can move on to developing new treatments for bone problems in space. Hopefully by the time our brave astronauts set foot on Mars we will be able to heal a bone fracture as effectively as we do here on Earth. Either that or we finally get the artificial gravity generators that have allowed space travel in all of the best sci-fi stories, but I won’t hold my breath on that.

Want to learn more? Visit http://magazine.colostate.edu/issues/fall-2014/bones-in-space/ and https://www.researchgate.net/publication/236272417_AN_OVINE_MODEL_OF_SIMULATED_MICROGRAVITY

Jan. 7, 2018

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