Mars scientists push NASA to send a rover to collect stones at two sites

The next NASA rover – the first to bademble Rock samples intended to return to Earth – should dream big and visit as many places as possible of the red planet, scientists concluded Oct. 18.

This would probably include a combination of the Jezero crater, which once housed river deltas and a lake; Northeast Syrtis, which contains some of the oldest rocks of Mars; and Midway, a compromise option in between. The project scientists proposed to visit Jezero, for the sediments of the river and lake that might retain traces of past life, and Midway, for ancient rocks.

Both are about 28 kilometers from each other – an ambitious yet achievable distance.

"The community prefers a mega-mission," says Bethany Ehlmann, scientist in planetary science at the California Institute of Technology in Pasadena. "If we want to return samples, there must be a cache sample for all ages."

The Columbia Hills area, which NASA's Spirit Hunter explored between 2004 and 2011, ranked much lower in the survey of scientists, despite having silica deposits similar to those formed by hot springs. (The ice-covered region near the south pole of Mars, where ESA's Mars Express recently detected what could be a buried lake was not on the list.)

The decision as to the The place to send the rover 2020 ultimately falls to NASA Chief Scientist Thomas Zurbuchen. who will choose in the coming months.

"I would love to receive any sample," says Meenakshi Wadwha, scientist in planetary science at Arizona State University in Tempe. "But we have the luxury of being able to choose between good sites."

Move the voices

Scheduled to be launched in July 2020, the $ 2.4 billion rover will be the first of all nations to collect rocks and martial balls. hide them for a future mission to bring back to Earth. The geology of the landing site has to be intriguing enough – and the potential scientific discoveries out there big enough – to make the mission worthwhile.

NASA did not anticipate how it would recover the rocks picked up by the 2020 rover. However, the agency convened Mars experts in Glendale, California from October 16-18 to badess four finalists for the rover landing site.

Jezero, Northeast Syrtis and Midway were remarkably close together, thanks to the votes of 158 scientists gathered during the workshop. The researchers ranked the sites according to several criteria, such as the potential of the samples collected on the data collected on each site to answer crucial scientific questions about Mars.

L & 39 The idea of ​​visiting Jezero, then Midway – or Conversely, last year, mission scientists debated how to make the most of the rover's journey. "It's ambitious," said John Mustard, planetary scientist at Brown University in Providence, Rhode Island.

Midway contains ancient rocks similar to those of Northeast Syrtis, near the network of rivers and lakes of Jezero.

Dangerous Trail

The sending of a rover to Jezero and Midway would require a bet that the vehicle will last that long. Its main mission is 1.25 Martian years (2.35 terrestrial years); during this time, it is planned to travel about fifteen kilometers. This would reroute almost the entire tour of the Jezero site, if it started there, and maybe even to the edge of the crater. But then this would face a hike through a dune-strewn area up to Midway. "The reward is absolutely worth the risk," says Mustard.

NASA's Curiosity rover, the largest and most powerful of the agency to date, has traveled more than 19 kilometers since landing on Mars in 2012. Engineers developing the 2020 rover expect to being able to travel faster than Curiosity, partly because of the new technology that improves his ability to navigate alone.

An important question is how many rock samples the rover will collect and from where. The 2020 rover is equipped with 42 thin sample tubes like a pencil, five of which will be reserved as spare parts in case of a problem, as long as it will try to drill and collect materials at the same time. using his robotic arm. This leaves 37 tubes to fill the most valuable extraterrestrial rocks ever collected.

"Sooner or later, somebody will have to decide if these samples deserve to be reported," project scientist Ken Farley told NASA's Jet Propulsion Laboratory (JPL) in Pasadena. . "I do not want to fail because we have not been ambitious enough to make the cache scientifically worthy."

A Treasure

At the workshop, the project scientists outlined options for filling these 37 tubes. They range from pieces of lacustrine deposits to Jezero, huge blocks of rock from the edge of the crater to the ancient rock of Midway. The nuclear-powered rover has several possible routes to cover the 28-kilometer stretch of dune fields between Jezero and Midway. According to Katie Stack Morgan, project scientist and project badistant, driving this distance would take about 401 Martian days.

We still do not know where the mobile could store its precious samples. One possibility is that he can collect two identical sets of samples from Jezero, drop one and drop a second set on the way to Midway, Farley told the meeting. This would leave the possibility of getting the samples back to Jezero if something went wrong with the rover en route to Midway.

NASA has not yet decided whether it would seek samples or how it could recover them, although tentative plans call for the launch of a mission in the late 2020s. "We are really serious about bringing back those samples, "Zurbuchen told the meeting. "That's why we are here."