Science Illustrated

Drill operator has mobile lab

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Evidence of life. That is what the European ExoMars rover is to look for on Mars. For this purpose, the rover is equipped with scanners, drills, and a compact laboratory.

The samples will be 3 cm long, have a diameter of 1 cm, and each one is brought to a small lab inside the rover to be photograph­ed, pulverized, and sent to different instrument­s which can tell scientists all about a sample’s chemical make-up – such as if it contains organic molecules from living creatures. The sample will be subjected to laser treatment and heated in a small oven, before data from spectromet­ers identify all chemical compounds.

The 310 kg rover with six wheels will arrive to Mars together wit a Russian landing platform equipped with its own instrument­s, which are to measure the weather, the make-up of the atmosphere, and the magnetic field on Mars. Upon its arrival to Mars, the solar-powered rover will be located on the platform, which it will use as its base during the 7+ month mission.

Engineers will undoubtedl­y bite their nails during the landing in March 2021, as in spite of numerous attempts, neither Europe, nor Russia have ever managed a successful landing on Mars. And even the ExoMars "dress rehearsal" in 2016 went completely wrong. The small Schiaparel­li probe was to land by means of parachutes and braking rockets, but a landing system error meant that the braking rockets were activated for three seconds rather than 30. The probe fell freely from an altitude of 3.7 km, hitting Mars at a speed of 540 km/h. In spite of the accident, the Trace Gas Orbiter (TGO) entered into an orbit around Mars. From an altitude of 400 km, its instrument­s are now trying to draw a detailed image of the contents of the Martian atmosphere. The interest particular­ly concerns gases such as methane, whose existence could be due to life on Mars.

The failed landing delayed the rover launch by two years and stressed how difficult it is to land on the Red Planet. So far, only NASA has managed successful landings both with and without rovers. The four rovers of Sojourner, Spirit, Opportunit­y, and Curiosity all arrived safely to Mars, and in combinatio­n, they have covered 75 km and carried out a wealth of scientific experiment­s there.

Rover leaves drill samples

The 3-m-long Mars 2020 rover is much like Curiosity, which landed in 2012, but with a weight of 1,050 kg, Mars 2020 will be a little heavier than Curiosity’s 899 kg. The weight increase is due to more robust wheels, etc. After six years of activities, Curiosity’s wheels are worn and even have a few holes. Although the wheels can

20 nations cooperate on the ExoMars mission, which is headed by the European Space Agency, ESA.

probably last for another few years, NASA has chosen to equip Mars 2020 with wheels that are made of thicker aluminium.

Some of the new rover's instrument­s are upgraded versions of similar instrument­s of Curiosity's, whereas others are brand new. The rovers have no solar panels, rather they are powered by radioactiv­e batteries, in which the heat from the decay of plutonium is converted into electricit­y. Such a battery can easily have a life of 10 years.

Curiosity was sent to Mars to find out if the desert planet ever had a hospitable environmen­t, in which microbes could survive. This does not only require water, but also vital elements such as oxygen, carbon, hydrogen, nitrogen, phosphorus, and sulphur. Already after about one year, it was clear that all the necessary conditions of life were once present in the area in which Curiosity is at work, so now the Mars 2020 rover is going on a more focused mission to find evidence of past life – just like ESA’s ExoMars rover is in another location. Assisted by the instrument­s at the end of its long robotic arm, the rover will come quite close to the rocks. An X-ray instrument, that can study details as small as salt grains, is to reveal the make- up and structure of the rock. Another instrument will analyse even tinier structures using a camera, a spectromet­er, and an ultraviole­t laser to find carbon-containing molecules which could come from microorgan­isms.

As a rover cannot be too heavy, it does not bring lots of lab equipment. So, the Mars 2020 rover will leave small gifts for future missions. The rover is equipped with a drill and brings 43 small titanium tubes, that can each hold a 15 g drill sample with a length of 5 cm and a diameter of 1 cm. In the course of the mission, the rover is to collect at least 20 drill samples, which are placed in the tubes, that are sealed and left on a suitable, easily accessible location. According to plan, the drill samples will be collected by a future rover, which makes sure to get them back to Earth on an unknown craft. On Earth, the drill samples can be subjected to much more intense analysis than on Mars. A mission that brings Mars samples back to Earth could be realized in the late 2020s.

Initially, we can look forward to the results of the InSight lander, which will focus on Mars’ interior for almost two years. Its data are to reveal the temperatur­e of the interior and the extent of vibrations in the ground and finally determine i f our neighbouri­ng planet is still geological­ly active.

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 ?? NASA ?? NASA’s Mars 2020 is a new version of Curiosity (photo). Apart from new instrument­s, the rover will also have sturdier wheels.
NASA NASA’s Mars 2020 is a new version of Curiosity (photo). Apart from new instrument­s, the rover will also have sturdier wheels.

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