[ad_1]
In order to completely eliminate this type of risk, in 2003 NASA used the last fuel stored in the spacecraft to plunge it into Jupiter's atmosphere. At a speed of 30 miles per second, Galileo evaporated in seconds.
NASA repeated this scenario of protecting the moon 14 years later. The Cassini mission orbited and studied Saturn and its moons from 2004 to 2017. In September 2017, when the fuel was almost exhausted, the Cassini operators deliberately plunged the satellite into the atmosphere of Saturn, where it disintegrated .
Mars is the target of seven active missions, including two rovers, Opportunity and Curiosity. On November 26, NASA's InSight mission is expected to land on Mars, where it will measure the interior structure of the planet. With planned launches for 2020, the European Space Agency's ExoMars rover and NASA's Mars 2020 rover are designed to look for evidence of life on Mars.
Robotic robots pose little risk of contamination in Mars, as all spacecraft designed to land are subject to strict sterilization procedures prior to launch. These rovers will likely have an extremely small number of stowaways.
Any terrestrial biota that manages to hitch up outside these vehicles would have a hard time surviving the journey of half the Earth between Mars and Earth. The vacuum of space combined with exposure to rigorous X-rays, ultraviolet light and cosmic rays would almost certainly sterilize the exteriors of any spacecraft sent to Mars.
Any bacteria that would have infiltrated one of the rovers could get to Mars alive. But, if there were any, the fine Martian atmosphere offered virtually no protection against high-energy sterilizing radiation from space. These bacteria will probably be killed immediately. Because of this hostile environment, life on Mars, if it exists now, must almost certainly hide beneath the surface of the planet. No rovers have explored caves or dug deep holes in search of possible Martian microbes.
Since Mars exploration has so far been limited to unmanned vehicles, the planet will likely remain free of terrestrial contamination.
But when Earth sends astronauts to Mars, they will travel with vital support, energy supply systems, habitats, 3D printers, food and tools. None of these materials can be sterilized in the same way as a spaceship. Human settlers will produce waste, try to produce food and use machines to extract water from the soil and the atmosphere. By simply living on Mars, human settlers will contaminate the planet.
It is essential that every effort be made to obtain evidence of past or present life on Mars well in advance of future Mars missions including human beings. What we discover could influence the decisions to send settlers there.
Even if we ignore or do not care about the risks that a human presence would pose to Martian life, the question of bringing back Martian life to Earth has serious social, legal and international implications that deserve to be examined before it's too late.
What risks could Martian life pose for the terrestrial environment or human health? Does a country or group have the right to endanger all life on Earth?
Nasa, the UAE's Space 21, Mars One and Blue Origin projects are already planning to transport settlers to build cities on Mars.
• Weintraub is a professor of astronomy at Vanderbilt University in Nashville, Tennessee. This article was first published on www.theconversation.com.
[ad_2]
Source link
