Protecting the value of scientific exploration "Planetary protection" to prevent microbial contamination - first MMX round trip to Mars

The probe ``MMX'' will be launched in the early hours of the 20th, aiming for a round-trip flight to the Martian moon ``Phobos''. Although it will be the first time in the world to return from Mars, it has carried out a variety of tasks that no previous Japanese probe has done to prevent environmental contamination from Earth's microorganisms and to protect the planet from bringing unknown microorganisms back to Earth upon its return.

Sample return, inheritance and development Mr. Tsuda of Hayabusa2 - Launch of space probe MMX

International rules have been established for the measures that must be taken to protect the planet. The icy moons of Mars, Jupiter, and Saturn are important exploration targets for exploring the origins of life, and if they become contaminated with microorganisms brought in from Earth, they lose their scientific value. In addition, missions that bring back samples will require safety evaluations from the perspective of preventing biohazards caused by unknown extraterrestrial microorganisms, and appropriate countermeasures will be required.

The Hayabusa2 spacecraft, which brought back samples from the asteroid Ryugu, did not take any special measures to protect the planet. Because the surface of Ryugu is exposed to radiation for a long period of time, it is unlikely that life could exist there, and it was determined that even if microorganisms were brought in from Earth, they would not survive.

Meanwhile, on the MMX orbiting Mars, a microbial survey was conducted on the aircraft and the assembly environment, taking into account the impact if it were to fall. A new inspection facility has also been established at the Kagoshima Tanegashima Space Center, where the launch site is located.

According to the Japan Aerospace Exploration Agency (JAXA), airborne particles in the surrounding area are collected at various milestones such as during assembly at the factory, transportation to Tanegashima, and loading onto a rocket. They even wiped down the soles of the landing gear, and it was confirmed that the number of microorganisms was less than one-tenth of the standard value.

Regarding the samples to be brought back from Phobos, it was pointed out that because the distance from Mars is close, approximately 6,000 kilometers, there is a risk that microorganisms may be contaminated if there were microorganisms on Mars. This is because sand from the Martian surface that was kicked up by a meteorite impact may have arrived, but JAXA estimated in simulations that the rolled up sand collides with the Phobos surface at several kilometers per second, so even if it contained microorganisms, it would be almost completely wiped out. A simulation experiment of an actual collision was also conducted, and its validity was recognized internationally.

JAXA Associate Professor Shunta Kimura, who was in charge of the inspection, emphasized, ``This is an activity to protect the value of future scientific exploration.We are doing this as a responsibility for the next generation.'' Ushi Ozawa, chief research and development officer, also said, ``We would like to carry out planetary protection activities that will lead to exploration and landing on Mars.''