The Perseverance rover also placed the 10th sample in a titanium cylinder where it stored them on Mars, and they will remain there to be picked up by a later mission, the BBC reported.

The samples are from heterogeneous rocks and soil.

The depot is a backup - to be returned to Earth if Perseverance fails to complete the next stage of its mission.

The site is carefully documented.  

Examining samples from Earth is the best way to determine whether life once existed on the Red Planet. 

NASA unveiled its plan to return Martian samples to Earth in 2033.

"Perseverance" was sent to Mars to explore the 45 km crater Jezero (Jezero).

This place is believed to have had a lake billions of years ago.

In addition, there are remnants of a delta at its western end.

Traces of microbial organisms may have lingered there.

Perseverance drilled a variety of volcanic and sedimentary rocks that should tell the story of the crater and lake.

Samples of these rocks are now located in the Three Forks area landfill.

They are not the main ones that NASA wishes to return to Earth.

It's more of a "plan B".

Perseverance stores copies of the Three Forks samples in a special place in its "belly".

NASA's Mars rover has taken its first sample from the Red Planet's surface

Plans are for the rover to be able to directly transmit these samples - and others yet to be taken - to the mission that will come to retrieve them for delivery to Earth.

But NASA doesn't want to take any chances and that's why the backup depot. 

The rover is about to climb atop the delta, accompanied by its reconnaissance drone.

The Injinuuti mini-helicopter has already begun its ascent.

Perseverance will be exploring terrain where there appears to have been a flood, judging by the large scattered boulders.

The robot will then move to the rim of the crater, where, according to satellite images, there are carbonate-type sedimentary rocks.

They will again be a good place to look for traces of ancient biology.

Perseverance's failed attempt to collect a sample from Mars

At Perseverance, there are still more than 20 test tubes waiting to be filled, BTA adds.

NASA

rover