NASA's Mars rover Perseverance is about to begin its historic hunt for signs of ancient life on the Red Planet.

The rover has been working seven days a week to test and practice with its various sophisticated instruments which will start taking soil samples soon from the Jezero Crater, which scientists believe was once a lakebed about 40 kilometers wide and possibly caked with dried mud that may hold evidence of potential primitive life.

"We are looking very, very far back in the history of the solar system and what that means is that life would not have had much of a chance to advance very far," NASA Perseverance Mars Rover Project Scientist Ken Farley said during a news conference to announce some of the early scientific results of the rover.

"We only expect, if there is life, that it would be microbial," he said.

Scientists believe the meteor impact that formed the Jezero Crater likely created an environment friendly to life.

There is evidence of ancient river flow into Jezero, forming a delta that has long since been dry, NASA says on its Perseverance 2020 mission website.

It says the rover's instrument revealed the crater contains clays which only form in the presence of water.

Farley described the current environmental conditions on Jezero, saying rover has sent back fascinating images of wind gusts and dust devils, which just like on Earth, are vortices that lift dust into the air.

"We're getting photobombed by dust devils," Farley said.

Among the questions the scientists are hoping to one day answer is whether the soil in Jezero is sedimentary or volcanic, and whether the ancient lake that once filled Jezero went through multiple episodes of filling up and drying down again.

"This is very important because it means that we will have multiple time periods in which we could potentially learn about environmental conditions on Mars," Farley said.

"We also have multiple time periods when we might be able to look for evidence of ancient life that might have existed on the planet."

Among the exciting observations are finely layered rock whose simplest interpretation, Farley said, is that they represent deposits on the bottom of the lake - in other words, mud.

"This is exactly the kind of rock that we are most interested in investigating for looking for potential bio signatures," he said.

The rover will take actual samples from the Martian surface for long-term storage during the first couple of weeks of August, Project Manager Jennifer Trosper said at the news conference.

A sophisticated "sample caching system" will put the soil samples into tubes using the rover's robotic arm, then transfer them into a "carousel" built into the front portion of the rover where another handling arm will do some basic imaging and measuring, before the sample tubes are sealed and stored in the rover's underbelly "for planned future return to Earth", Trosper said.

She said NASA has been preparing for that first sample, checking out the caching system and working with so-called "witness tubes".

They are similar to the sample tubes but were preloaded on Earth with materials that can capture molecular and particulate contaminants.

They are opened on the Martian surface to "witness" the ambient environment near sample collection sites and will help scientists know whether Earth contaminants were present during the Martian sample collection.

Trosper said other experiments carried out by the rover include Moxie, whose purpose is to demonstrate for future missions the ability to extract oxygen from the carbon dioxide atmosphere.

The rover has done three Moxie runs to date and those were successful, Trosper said. The experiment will help provide future missions oxygen for human astronauts to breathe, she said.

Courtesy: NASA TV