Is there life on Mars? Well, to seek that answer, scientists are planning even more daring space missions – and Perseverance, for example, is already packed to investigate the planet and bring some souvenirs from there. In the near future, around 2030, it is expected that the agency will finally be able to bring Martian pieces. However, a question remains in the air: could these samples pose a danger to Earth?
At first, the risks are very low. Still, they have not been completely ruled out. To calm things down, a guide called “Planetary Protection” sets out rules to protect both other celestial bodies from earthly contamination and our planet from contamination from other unknown life forms. In this case, samples from Mars would be brought on a trip considered restricted, according to Cassie Conley, a former program officer.
These measures were stipulated precisely to prevent disastrous consequences for our environment. After all, the coronavirus is there to show us that we are not even prepared for new organisms that have emerged even here. “We don’t understand Earth’s biology very well and we certainly don’t know much more about Mars. So, it is premature to consider that there are no Martian biomes ”.
“The pandemic we are going through tragically demonstrates how overconfidence in a short period of time can cause real catastrophes,” says Conley.
The dangers of adaptation and the numerical advantages
Andy Spry, a senior scientist at the SETI Institute and a consultant to NASA, points out that public interest in these security issues tends to increase after covid-19, as in the case of measures taken after past cases that made it possible to respond to the current pandemic. Therefore, it is assumed that the actions will become even more effective, allowing a coexistence of life forms and adaptations that do not cause complete disasters.
For example, even if such samples contain “hosts”, in the event of contamination, the main objective is that they do not overlap with earthly life. However, this is only possible with trial and error – and the more control, the better.
“We can think of pathogenicity [an organism’s ability to cause disease] as locks and keys that don’t develop without repeated contact. Therefore, it is extremely unlikely that an evolving and adapting biological entity on Mars can take advantage of Earth’s life forms ”, says the scientist, referring to the fact that, from a small sample, the Martian’s attempt to survive will result in an almost certain error. After all, if the pathogen dies without finding a host in which to grow and reproduce, its story ends there.
On the other hand, this does not mean that the agency will make things easier.
The price of security
The main nations that undertake space missions share a common perspective of containing these materials, but Andy reinforces that, according to the international policy of the Space Research Committee, no unsampled hardware that has contacted Martian soil will be returned to Earth. Yes, Curiosity made a one-way trip to send photos to humans. Still, a lot needs to be defined. “The details of Perseverance’s mission are being aligned. We are about 15 years before the return really happens, which is enough time to make everything right ”.
“We have technology to take care of that, but we should have a clearer idea of what we can find,” ponders Dirk Schulze-Makuch, an astrobiologist at Washington State University. After all, in addition to life itself, the probe will search for evidence of past organisms.
“So, I assume that the guidelines would justify a high-level recovery of biosafety, which means a very high investment. As samples can only be brought after the complete installation of this structure, the schedule can be delayed. We need ‘fresh’ samples, which are not stored indefinitely waiting for the return ”.
They will not be the first nor the last
Also according to Dirk, the Earth already has a lot of Martian stuff coming from meteorites. These bodies may even have already brought microbes from there, if they exist. “Studies have shown that the interior of the ALH84001 sample [a Mars rock found] has never been heated above 40 degrees Celsius. If there were any microorganisms, it would probably survive the journey ”.
“Anyway, the point is that there is already a natural mechanism at work that makes it possible for Mars to arrive on Earth. If this has not had a negative role in the development of terrestrial life in the past, it is unlikely to have it in the future ”, he assumes. “Still, we have to admit: the risk is not zero”, he concludes.