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The rover is based on the footprint and structure of Curiosity, and is in fact equipped with a radioisotope thermoelectric generator, a generator of heat and electrical energy, based on the radioactive decay of plutonium, to power and heat the rover, as the temperature average on the surface of Mars is −63 °C.
Compared to Curiosity, however, the rover was equipped with an improved landing system. In particular, it was able to count on two evolutions, the Range Trigger and the Terrain-Relative Navigation. The Range Trigger is the system that controls the timing of the opening of the parachutes during descent.
By knowing one's position with respect to the expected landing site and by delaying or anticipating the opening of the parachutes, it was possible to reduce the landing ellipse, i.e. the estimated arrival area, by 50%, thus reducing the risks of finding oneself in inaccessible areas or of little interest.
Before then, the parachutes of the various probes that arrived on Mars were always opened as soon as the capsule reached a speed suitable for doing so; with this system, however, the parachute was opened at the most useful moment to get as close as possible to the landing site, obviously always remaining within the required speed parameters.
For example, if the control system had noticed that the site had been exceeded, this would have commanded an earlier opening than expected; in the opposite case the opening would have been postponed by increasing the distance traveled in the fall.
What are the technical characteristics of the Mars 2020 mission rover
Terrain-Relative Navigation is a new system for determining the characteristics of the ground in the very last stages of landing. The computer that governed this phase of the mission had pre-loaded a high resolution map of the landing site, created in previous years by the probes currently in Martian orbit and containing in turn all the areas that were dangerous or not recommended for landing.
During its descent, the rover collected images in rapid succession of the area it flew over and by comparing them with the known map it calculated its position and the estimated arrival area. If the calculated position had been considered dangerous the navigation system could have moved the landing to a preferable area within a radius of 300 m.
Previously, areas considered interesting due to the possible presence of traces of biological compounds or particular geological structures were discarded because they presented 99% of possible dangers. With this navigation system, however, it was possible to choose landing areas that were previously precluded, allowing the selection of areas with dangers that could then have been avoided by Terrain-Relative Navigation.
Also during the descent phase, the MEDLI2 suite of instruments was also active, i.e. the second generation of the MEDLI suite, which collected data such as atmospheric pressure and temperature and the heat shield, allowing the Martian atmosphere to be better characterized for future missions.
During the landing several cameras were active, allowing all phases of the landing to be filmed: one camera filmed the parachutes, one the ground below on the descent stage, one was pointed upwards towards the descent stage and one another towards the ground. There is also a microphone that collected the sounds during all phases.
