The intensification of space missions opens up new challenges: the recent study on the risks of contamination between terrestrial life forms and alien worlds.
The entry into what they call the new space age brings with it old issues and new questions. The intensified presence of human activities beyond the Earth's atmosphere is already showing its most immediate effects, ranging from the danger of impact with the - increasingly numerous - fragments of space garbage to the need to establish a common protocol to communicate the possible discovery of alien life forms.
The risks of human activity
A new McGill University study published in the journal BioScience analyzes the consequences of human expansion into space from the particular perspective of the risk of biological contamination.
The prospect of intercepting alien life forms is becoming increasingly likely, at least according to what NASA publicly states, and the near future will see some of the most important space missions ever planned by Earthlings.
With several rovers strolling around Mars, soon to be joined by ESA's ExoMars, with the mission in the works that will bring back samples of the Red Planet's soil to Earth, and several missions planned to the moons of Jupiter and Saturn, the human presence beyond Earth's atmosphere is starting to take its toll.
But the risk of inadvertently "creating" new life forms will increase dramatically, the study says, by the time the first long-duration mission to Mars is attempted, where the need for "organisms capable of generating food, processing waste, producing biogas" will inevitably lead to unpredictable advances in bioengineering.
The "alien" bacteria from which to protect the Earth and other celestial bodies affected by human activities, according to the study by Anthony Ricciardi and colleagues, are those that could originate from possible uncontrolled contamination. The risk is quite real, warn the scholars: similar bacteria have already been detected both on the hull of the International Space Station, and inside the Kennedy Space Center of NASA.
The danger comes from our planet
The danger of contamination by alien life, however, comes from Earth: the terrestrial life forms that travel in space with the space exploration missions in fact, if exposed to special conditions, can change unexpectedly.
A recent experiment has shown that the cells of an extremophile bacterium, Deinococcus radiodurans, can survive on the outer surface of the ISS in orbit for up to three years: this means that it is potentially possible to transfer such life forms between Earth and Mars, even unintentionally.
The case of the Kennedy Space Center is even more indicative of the possible dangers of contamination: in 2014, inside a clean room in which the Phoenix ship was being assembled, a bacterium never before described was detected. The bacterium proved to be resistant "to extreme doses of ionizing radiation, dehydration and disinfectants," as if it had evolved in an environment entirely different from Earth's.
The evolution of terrestrial life forms in space is unpredictable, which is why scientists claim that the possible contamination of distant planets is "an event comparable to a natural disaster." A blatant example of how real the risk of alien contamination is came from the Israeli mission that in 2019 saw the lunar lander Beresheet crash on the surface of the Moon.
The Israeli lander contained thousands of tardigrades in a dormant state inside a solid compound: there is no real danger that the tardigrades could wake up to invade the Moon, but since then the scientific community's attention on the risks of biocontamination related to space exploration has inevitably become more pressing.