The fact that we can walk the surface of Mars while you read this is an extraordinary fact.
The robot Perseverance , which has the size of a car, landed safely on the Martian surface on last February. It may only advance at a maximum speed of 152 meters per hour, but it consists of a series of instruments with which it has carried out experiments with revolutionary results.
On board the three-meter-long robot is a machine that has converted Martian air (thin and full of carbon dioxide) into oxygen, as well as a helicopter that made the first motor-controlled flight on another planet.
The helicopter, called Ingenuity, has successfully carried out three flights, covering ever greater distances.
But is it possible that something else has reached Mars with all these devices? Could a bacterium or spore trail from Earth have been accidentally transported into space and survived the journey to make the red planet its new home?
“Almost impossible” to avoid
NASA and its engineers at the Jet Propulsion Laboratory (JPL) have precise and comprehensive protocols to ensure that their spacecraft spacecraft are free of any organisms that may inadvertently sneak into a space mission.
However, two recent studies show how some organisms could have survived the cleaning process and also to the trip to Mars , as well as the speed with which microbial species can evolve in space.
First, let’s tackle how the Perseverance was built , as well as most of the spacecraft manufactured at JPL’s Spacecraft Assembly Facility (SAF).
The buildings are painstakingly built, layer by layer like an onion, and each part is cleaned and sterilized before assembly . This methodology ensures that almost no bacteria, viruses, fungi or spores contaminate the equipment that will be sent on a mission. They are built in rooms with air filters and strict procedures for biological control , designed in such a way as to ensure that only a few hundred particles can be present and ideally no more than a few dozen spores per square meter. But it is almost impossible to have zero biomass. Microbes have been on Earth for billions of years and are everywhere. They are found in our bodies and around us. Some can sneak into even the most sterile places. In the past, biological contamination tests were based on the ability to grow life (in crops) from samples taken from an object, such as spacecraft. Now we use newer methods. We take a certain sample, extract all the DNA and then do a “shotgun” sequencing or shotgun sequencing . The term is used because it is like putting the sample cells in a shotgun, “shoot” them into thousands of millions of tiny DNA fragments and then sequence each piece. Each “read” sequence can be reassigned to known genomes of species that are already present in sequence databases. Since we can now sequence all the DNA that is present in sterile environments, and not just the ones that could be cultured, we get a more complete view of what kinds of microbes can be found there and if they could survive the vacuum of space. In the sterile environments of JPL we found evidence of microbes that have the potential to be problematic during space missions. These organisms have a greater number of DNA repair genes, which give them greater resistance to radiation, are cap Aces to form biofilms on surfaces and equipment, they can survive desiccation (loss of moisture) and thrive in cold environments. It turns out that in these sterile environments a evolutionary selection process of the most resistant insects that would later have a greater probability of surviving a trip to Mars. These findings have implications for the so-called “interplanetary pollution” originating from the Earth. It is important to guarantee the safety and preservation of any life that may exist in other parts of the universe, since organisms come from other ecosystems could wreak havoc. Humans have a hi Negative history of this on our own planet. Smallpox, for example, was spread among indigenous peoples of North America in the 19th century through donated blankets. Even now we have not been able to contain the rapid spread of the virus that causes covid – , SARS-CoV-2. Direct contamination is also undesirable from a scientific perspective. Scientists, if they discover any kind of life on another planet, should ensure that it is genuinely native and not a false record of something with an extraterrestrial appearance but coming from Earth. And it is that their genomes could change so much that could come to seem from another world , as we have seen recently with the microbes that evolved on the International Space Station. Although NASA works hard to prevent the introduction of such species on Martian soil, any sign of life on Mars would have to be carefully examined to make sure it did not originate here on Earth. Failure to do so could generate an e Misunderstanding of the characteristics of Martian life. Microbes transported into space may also be of more immediate concern to astronauts, posing a risk to their health and may even cause life support equipment to malfunction if it becomes filled with colonies of microorganisms. But planetary protection is bidirectional. We must also avoid bringing back “pollutants” from another planet that may endanger ours and ourselves. This has been the basis of many science fiction films, where an evil invader “alien” threatens to destroy you All life on Earth. But it could become part reality with the mission that NASA and the European Space Agency plan to deliver to Mars in 2028 and that, if the provisions are fulfilled, in 2032 will bring back the first samples of the red planet. However, considering that the first two Soviet probes landed on the Martian surface at 1200, followed by the US Viking 1 lander in 1976, it is likely that already has some fragments of microbial, and perhaps human, DNA in the Red planet. Even if Perseverance, or the missions that preceded it, had led accidentally organisms or DNA from Earth to Mars, we have ways of differentiating it from any life that is truly of Martian origin. Hidden within the DNA sequence will be information about its provenance. An ongoing project called Metasub is sequencing DNA found in more than 100 cities of the world. Researchers From our lab, the Metasub teams and a group in Switzerland have just published these and other global metagenomic data to create a “planetary genetic index” of all the sequenced DNA ever observed. By comparing any DNA found on Mars with sequences seen in the sterile environments of JPL, the underground world, clinical samples, sewage or the surface of the Perseverance robot before it left Earth, it should be possible to see if they are really unknown. Even if our exploration of the solar system has inadvertently carried microbes to other planets, they are likely not the same as when they left Earth. Space travel trials and unusual environments where they are make them evolve . If an organism on Earth has adapted to space, or Mars, the genetic tools at our disposal could help us discover how and why microbes changed. In fact, the new species recently discovered on the International Space Station by scientists from JPL and our laboratory were similar to those found in sterile rooms (capable of withstanding high levels of radiation). As more and more extreme biology is recorded in a program called the Extreme Microbiome Project, there is also the possibility of using evolutionary tools for future work here on Earth. We can use their adaptations to search for new sunscreens, for example, or new DNA repair enzymes that can protect us against harmful mutations that lead to cancer, or help the development of new drugs. Eventually, humans will set foot on Mars, taking with us the cocktail of microbes that live on our skin and within our body. It is likely that these microbes also adapt, mutate and evolve. And it is also possible that ap Let’s render them, as unique genomes that are adapted to the Martian environment could be sequenced, transmitted to Earth for further schematization, and then used for therapy and research on both planets. Given all the Martian missions that are planned, we are on the edge of a new era of interplanetary biology , in which we will learn about the adaptations of an organism on one planet and we will apply them to another. The lessons of evolution and genetic adaptations are inscribed in the DNA of each organism, and the Martian environment will not be different. Mars will leave its mark on organisms that we will see when we sequence them, opening a completely new catalog of evolutionary literature. This will not only feed our curiosity, but it is a duty of our species to protect and preserve all other species. Only humans understand extinction and therefore only humans can prevent it. And that is applicable today, but it will be in billions of years from now, when the Earth’s oceans start to boil and the planet becomes too hot for life to exist on it. Our inevitable violation of planetary protection will occur when we start heading towards other stars, but in that case, we will have no other choice. Eventually, careful and responsible interplanetary pollution is the only way to preserve life. Christopher Mason is Professor of Genomics, Physiology, and Biophysics at Weill Cornell Medicine, Cornell University in New York. He investigates the long-term molecular and genetic effects of human spaceflight, as well as the design of new cell types for cancer therapy. You may read the original version of this article in English on BBC Future. Now you can receive notifications from BBC News Mundo. Download our app and activate them so you don’t miss our best content. 
How to know?
The “interplanetary contamination”
Why would it be harmful?
Detect its origin
One aspect positive
