An experiment that was conducted aboard — or rather outside of — the International Space Station, proves that biological organisms can survive the harsh environment of space for extended periods of time. The experiment was designed investigate how human expeditions to Mars could one day sustain themselves, and how the biology of extremophiles — organisms that thrive in conditions that would be deadly to other creatures here on Earth — would fare in the harshness of space. The success of the experiment not only provided surprisingly positive results, it also offers new evidence that life on Earth may have originated from elsewhere in the cosmos.

The experiment itself was part of the BIOMEX (Biology and Mars Experiment) mission, organized by scientists from the Fraunhofer Institute for Cell Therapy and Immunology IZI in Germany. It involved two strains of cryophilic ("cold-loving") algae: Sphaerocystis, a native to Norway, and Nostoc, a blue-green algae normally found in Antarctica.

In 2014, samples of the two single-celled plants were partially dehydrated, and then placed in the EXPOSE-R2 experiment package outside the ISS for 450 days. There, the algae was subjected to not only the harsh near-vacuum found in Earth orbit, but also temperature fluctuations ranging between -4ºF (-20ºC) and 116ºF (47ºC), and what would otherwise be deadly amounts of ultraviolet and cosmic radiation.

After their long trip through space, the samples were returned to Earth, where researchers attempted to grow colonies from the exposed samples. Remarkably, only one of the samples failed to reproduce, with the others producing viable algae colonies, proving that biological organisms, albeit simple ones, can survive long-term exposure to the environment of low earth orbit. DNA analysis of the samples will be conducted, to determine the extent of damage caused to their genes by radiation from the sun.

The results of the experiment also support the Panspermia theory, the idea that life on Earth didn’t originate here, but was transported here from somewhere else in the cosmos. Dormant organisms hitching a ride with an asteroid or comet that impacted the early Earth, and eventually evolved over the eons to become the biology we’re familiar with today. If an organism can survive for 450 days in orbit, it’s not inconceivable that a similar organism could hitch a ride, either on or in, an asteroid hurtling through space.