A batch of algae has survived 16 months of direct exposure to outer space.
Quartz reports that a type of green algae and photosynthesizing bacteria remained alive while dwelling on the exterior of the International Space Station. Only one of the algae samples failed to resume growth after being brought back to Earth.
The experiment took place under the auspices of the Biology and Mars Experiment (BIOMEX) to learn more about the successes and limitations found when terrestrial life is exposed to conditions in outer space.
The terrestrial samples, which included algae, fungi, lichens, bacteria, and mosses, were positioned in pockets on the outside of the space station. There the samples were exposed to ultraviolet radiation, a near vacuum, and temperatures ranging from -4 °F to 116 °F.
The algae that survived belonged to species found in Norway and Antarctica. The polar algae are able to protect itself from extreme cold by forming a protective layer of thick walls and cysts while entering a dormant state.
The two algae species join the growing list of known organisms that can survive in space. The list includes bacteria, lichens, and tardigrades (better known as “water bears.”)
Space survival studies may help inform future attempts to grow food in hostile conditions, such as on the surface of Mars. Algae could also prove useful to space explorers because it produces proteins and oxygen.
BIOMEX studies can also add information to the debate regarding how life began on Earth. The leading hypothesis is that life formed from a serendipitous mix of chemicals under just the right environmental conditions. Another idea is that life was delivered to Earth via asteroids and/or comets, and proving that some forms of life could survive space travel is another finding in favor of that hypothesis.