It will be one of the most daunting, complicated and potentially scientifically rewarding missions ever undertaken on the red planet. At a recent meeting of the European Space Agency (ESA), the ministers have committed fully to the plans to collect samples from the surface of Mars and bring them to Earth, in a joint effort with NASA. The official approval of the NASA budget for cover this mission It is scheduled for early next year.
The mission, still without a name, will be carried out with a series of launches, starting in July 2020, with the Mars 2020 rover, which was already underway. It is a robotic nuclear-powered rover that will make a precise landing in the Jezero crater in February 2021.
In the three years from 1969 to 1972, six Apollo missions managed to bring 380 kilograms of lunar samples. The recovery of any sample of the Martian surface, however, is significantly more difficult due to the vast distances involved.
For this reason, the project comprises three separate spaceships. The first part of the mission is the deployment of the Mars 2020 rover. Even this will be daunting, it is notoriously difficult to land something on Mars. In addition to carrying out a series of own scientific investigations, the rover will collect up to 38 individual samples of Martian soil that will be stored in sealed containers. Samples will need to be kept safe until at least 2026.
The second part of the mission will be to take the samples back to orbit. At this time, a Mars sample recovery mission will be launched, again by NASA, which will deploy a landing module and a fetch rover built in Europe as close as possible to the landing site of the Mars 2020 rover, Another difficult landing.
The “fetch rover” will meet the “Mars 2020 rover” on the surface, collect the samples and return them to the landing module. Once on board the landing module, the samples will be transferred to a capsule in the Ascent Vehicle to Mars, a rocket with a mass as low as possible, which can still reach the Martian orbit from the surface. Once in orbit, this capsule will be allowed to float out of control.
The third part of the mission will be a return vehicle to Earth launched by ESA. It will enter the Martian orbit, then it will meet and couple with the sample capsule, collecting the sample capsule in orbit and depositing it inside a heat and radiation protective shield. Then it will start its engines once more and return to Earth. Upon arriving on Earth, the sample capsule will be released into the atmosphere and, without parachute help, will make a forced landing in the Utah desert, sometime in 2031. If everything goes as planned, of course.
This immensely complicated campaign will involve a series of innovative firsts, including the first rocket launch from another planet, the first return of samples from Mars, the first encounter and orbit coupling around another planet, and the first encounter of two different spacecraft on the surface of another planet.
The Jezero crater
The purpose of the project is to recover samples from one of the most interesting geologically areas of the Martian surface: The Jezero crater.
Jezero is a 45 km diameter impact crater that is located in the northern hemisphere, on the western edges of Isidis Planitia, a large flat plain that is also an impact feature. Research shows that Jezero seems to have once been a lake, with water entering the crater through canals, before heading east to Isidis.
The landing site of Mars 2020 is the fan-shaped deposit located at the opening of the western entrance channel, a feature that is believed to be formed by a river delta that extends over the surface of the crater. This area has high concentrations of smectite, a type of clay that often forms at the bottom of the lakes and has long been thought to play a vital role in the origin of life on Earth.
Smectite clays are also very good for preserving fossils and other organic materials. It has been theorized that microbial life is possible on Mars, since observations have shown that it has a seasonal cycle of methane and oxygen.
Methane is a key indicator of microbial life, and therefore this cycle suggests that or there is life under the ground of Mars, or methane is being stored in clathrates (a type of material that traps molecules) and released when heated during the Martian summer. If the Jezero crater once had microbial life, there is a good chance that there are fossilized remains on the ground, waiting to be discovered.
Ground analysis
We already have some knowledge of the Martian surface environment acquired from robotic spacecraft, but such analysis is limited by the hardware we can send there. By taking a sample to Earth we can make much more precise measurements that, crucially, are repeatable. Terrestrial laboratories are “future proof”, as new technologies are developed, samples can be re-analyzed more accurately.
In fact, the lunar samples recovered during the Apollo missions continue to give results today, about 50 years after they were collected.
Miniaturized instruments mounted on robotic spacecraft, such as microscopes and spectrometers, are capable, but their sensitivity simply does not match that of equivalent instruments on Earth, mainly due to limitations of mass, size and power requirements in a spacecraft .
On Earth, it will be possible to take images of Martian samples at scales thin enough to see the atomic structure and detect constituents in much smaller concentrations than would be possible on the red planet. Martian samples brought to Earth can also be accurately dated, potentially allowing scientists to answer the question of how long ago the water sat in Jezero. Any microbial fossil in the soil would also be visible with these techniques.
In addition, a better understanding of the material properties of Martian soil will inform engineers about its potential to be used as a future construction material. Such knowledge could be vital in planning future human explorations to Mars.
The complexity of this project gives an idea of how difficult it will be to send people to Mars and bring them back. If we succeed in this sample return mission, we are definitely one step closer to being able to send a manned mission to the red planet, with the samples returned revealing the most interesting places for us to visit in person.
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