An algae that survived more than 500 days in the International Space Station could be the answer to humanity's quest for a food that can be grown on planet Mars.
In a nearly two-year experiment conducted on the ISS, Thomas Leya, from the Fraunhofer Institute for Cell Therapy and Immunology in Potsdam, Germany, and colleagues studied how the extreme conditions of space can affect algae.
Algae Survived Extreme Condition Outside The Space Station
They found that a particular species of algae, which was placed on the exterior of the orbiting laboratory, survived the extreme temperature fluctuations, vacuum, as well as cosmic and UV radiation in space for a period of 16 months.
The algae that survived belonged to the Sphaerocystis species, which is found in the Norwegian archipelago Svalbard. Another organism that survived the harsh condition outside the ISS is a cyanobacteria that belonged to the Nostoc species found in Antarctica.
These species were selected for the study because they are known to be capable of withstanding extreme cold. The algae species protects itself by entering a dormant state wherein it forms thick walls and orange cysts that are rich in carotenoids, the chemical responsible for the carrot's orange color and is known to provide protection against radiation.
"The experiment shows that some terrestrial organisms are robust enough to cope with months of exposure to open space conditions without a space suit," said Rene Demets, from the European Space Agency who was not involved in the study.
The algae and bacteria are now added to the growing list of terrestrial organisms that can survive space. The list already includes other species of bacteria, lichen, and water bear.
The study was part of the Biology and Mars Experiment (BIOMEX), which aims to understand the extent at which terrestrial life can survive in space. The experiment involved hundreds of specimens of lichens, fungi, bacteria, mosses, and algae that were exposed to extreme conditions which include temperatures ranging from -4 °F (-20 °C) and 116 °F (47 °C), near vacuum conditions and continuous blast of ultraviolet radiation.
The organisms were transported into space on July 23, 2014 and endured 16 months on the outside of the ISS having only neutral-density filters to mitigate the effects of radiation. On June 2016, the BIOMEX lab was sent back to Earth, where researchers now conduct analysis of the DNA of what survived during the organisms' stay in outer space.
Key To Growing Food Sources On Planet Mars
Nearly all of the samples that returned from the orbiting laboratory developed into new populations. The green alga, in particular, developed orange-coloured resting stages.
Researchers want to know whether the DNA of the ISS algae was damaged and to what extent.
The findings could have significant applications such as in a mission to planet Mars someday. Producing food on the Red Planet is important for survival should humans colonize this extraterrestrial worlds in the future. Algae are known to produce proteins and oxygen, which makes them a good source of food.