A Mars Rover Has Now Driven Farther Than Any Vehicle on Another World, Mostly on Its Own

NASA's Perseverance rover has driven farther across the surface of another world than any vehicle before it, ScienceAlert reported. Most of that distance was covered by the rover steering itself rather than following step-by-step commands from Earth.

According to the outlet, the rover's odometer reached 45.22 kilometers (28.10 miles) on Oct. 11. That edged past the mark set by the Opportunity rover, which traveled 45.16 kilometers on Mars from 2004 to 2018.

How Perseverance covered the distance

ScienceAlert said Perseverance drove more than 90 percent of its record distance on its own, using a navigation system called AutoNav. Scientists on Earth set waypoints, and the rover scans the ground between them and picks a safe path across the rocky terrain.

The outlet noted that the technology has a long lineage. Sojourner, the first rover on Mars, landed in 1997 and covered around 100 meters. According to ScienceAlert, Sojourner took 20 measurement points of the path ahead, while Perseverance processes 200,000 with each look, as scientists at NASA's Jet Propulsion Laboratory have pointed out.

That speed lets the rover work out its route while moving, which the outlet described as “thinking while driving.” In a single Martian day, known as a sol, Perseverance can cover as much as 412 meters (1,351 feet). A sol is about 40 minutes longer than an Earth day.

ScienceAlert also pointed to the Ingenuity helicopter that traveled with the rover and became the first controlled aircraft to fly on another planet. Rather than the five test flights planned over 30 days, the outlet reported, it made 72 flights over three years, covering 17 kilometers and climbing nearly 24 meters in the thin Martian air.

Where the rover is now

Perseverance is currently on the western rim of Jezero Crater, in an area called Lac de Charmes. According to ScienceAlert, it is heading toward a spot named Idubi, which may once have been a hydrothermal system, the kind of environment thought to have helped life begin on Earth. Another target is Rainbow Falls, described as a chunk of Mars thrown out of the ground by the impact that formed Jezero Crater.

The rocks in the region are very old. Ken Farley, a Caltech geochemistry professor and former Perseverance project scientist, said they are “probably older than 4 billion years.” ScienceAlert noted that few rocks on Earth are that old, because erosion and plate tectonics have destroyed or recycled most of them. Some survive, however, and could hold traces of early life.

The outlet also recalled that Perseverance has examined a leopard-spot-patterned rock called Cheyava Falls, in an ancient basin that held water several billion years ago. ScienceAlert described the find as possibly the best evidence yet of past life beyond Earth, though the report did not present it as a confirmed discovery.

What it means for the search for life on Mars

The driving record is partly a milestone for engineering. The more a rover can navigate safely by itself, the more ground it can cover between instructions from Earth, and the more rocks scientists can reach and study.

The bigger question is what happens to the samples the rover has collected. ScienceAlert argued that the most useful place to look for signs of life is one from which samples can be brought home, and that Mars is a strong candidate because it was a wet world when life arose on Earth.

A return mission is the obvious next step, the outlet said, but NASA's Mars Sample Return program lost its funding earlier this year. That leaves the timing of any retrieval uncertain. ScienceAlert added that such a mission would also help inform future efforts to send people to Mars and bring them back safely.

For now, according to the report, Perseverance keeps working on the crater rim, adding to its record with every drive.

Around Prague, based on reporting by ScienceAlert