Perseverance is currently trying to cover more ground in a single month than any rover before it. At the end of this five-kilometre journey full of pitfalls, the vehicle will reach an ancient river delta that may harbor traces of past life.
In the summer of 2020, NASA took advantage of a launch window to send its Perseverance rover to the red planet. Landed in February 2021, its main objective will be to search for traces of past life on the planet and to put rock samples under seal. In this spirit, the American agency is focusing its investigations on the Jezero crater, a formation 45 km in diameter supposed to have housed a delta of rivers between 3.5 and 3.9 billion years ago.
This choice is not accidental. Indeed, we know from our terrestrial experience that deltas are very effective in preserving biosignatures thanks to the deposits of hydrated silica present in certain parts of the crater. If life on the red planet has already evolved, its vestiges may have been swept by the river to be deposited in this ancient delta of the Jezero crater which once housed a huge lake.
A recent analysis by researchers at Stanford University (USA) had also determined that these biosignatures would have had time to permeate the sediments. This delta thus appears to be one of the best places on Mars to look for signs of past microscopic life. But you still have to get there.
A journey full of pitfalls
Since its arrival on the red planet, Perseverance has indeed evolved several kilometers away. On March 14, mission leaders decided it was time to get back on the road to achieve this very promising training.
For this long trip of about five kilometers which should take about a month, the vehicle relies largely on its autonomous AutoNav system which has already set impressive distance records. This system, the most efficient ever designed and developed for a Martian rover, allows Perseverance to manage routes much faster than if humans programmed each of its movements.
AutoNav is particularly useful for journeys on flat terrain, with simple potential dangers. However, this new route will not be so simple. Along the way, there will indeed be several craters, sandbanks and other sharp rock fields that the rover will have to circumvent. The mission team will still be present to plan the basic route using images taken from space and “marking” the most dangerous obstacles.
On site, the scientific team will take images of the rocks to select the most interesting ones. The rover will then drill them to take cores. These samples will then be set aside for a return to Earth planned for the early 2030s as part of the Mars Sample Return mission.
