Scientists from the US space agency (NASA) rejoice with rock samples on Mars taken by the Perseverance rover last week. They moved the robot to take a second sample.
Perseverance drilled a rock core the size of an index finger on 6 September, and repeated the procedure a few days later.
Scientists believe the rock that was targeted is of volcanic origin, meaning it can be dated accurately.
This stone also contains salt, which indicates changes in water, and raises the possibility of life.
Or, at least, the potential of a past life.
There is not always life where there is H₂O but it is hard to imagine how organisms could live without it.
The Perseverance robot was sent to the Jezero Crater area on Mars, as it appears to have had a habitable supporting environment billions of years ago.
Satellite images show a lake once existed in the 45km wide crater.
In the western part of the crater, there are river deposits and wide paths.
The period in which this area of water existed is now narrowed down by rock samples that have just been taken.
The targeted plate, dubbed “Rochette” is on the surface of Jezero and is thus expected to represent the oldest layer in the crater.
If the mineral in the sample taken was known to be of age, it would be estimated to be “no older than” the age of the lake.
The salt – possibly calcium sulphate or calcium phosphate – is very interesting, because it almost certainly contains tiny inclusions, or bubbles, of water.
“Salt is a great mineral for preserving signs of ancient life on Earth, and we hope the same is true for rock samples on Mars,” said Perseverance project representative Dr Katie Stack Morgan.
Of course, in order to carry out this investigation, the sample would need to be sent back to Earth first.
Nasa’s plan (in collaboration with the European space agency) is to order Perseverance to collect more than twenty core rocks over the next two years, and package them in sealed titanium tubes.
Perseverance will briefly perch on the surface of Jezero for its next mission, collecting rock samples to transport to Earth before 2030.
“Due to … the high potential value of science, we decided to get two samples at Rochette,” Dr Stack Morgan told reporters.
“Scientist team [Perseverance] plan to put one or two of the same sample. And to make sure each sample of this kind is as complete as possible, we have a strategy of getting two samples in each of the highest priority locations.
To reach the Rochette rock site, Perseverance walked about 2.2km (1.4 miles) from its landing point, in February.
Currently, it is heading west along a slightly raised ridge to a location referred to as “Southern Séítah” where further rock cores will be retrieved.
On the other hand, the robot is tracked by a mini helicopter called Ingenuity, which monitors the ground in front of it.
At some point, scientists want the wheeled robot to move north to where river sediments and pathways are most visible, and where the chances of finding traces of past life are greatest.
Meenakshi Wadha is a scientist working on returning samples from Mars. He said the cores taken from Rochette had their own names “Montdenier” (September 6) and “Montagnac” (September 8).
“I’m not overestimating the importance of the rock samples collected by Perseverance. This is a truly historic achievement – core rocks collected for the first time on the mainland of another planet. It’s incredible.
“These two rock cores now represent early sampling from Mars.
I dreamed of having samples coming from Mars to analyze in my lab since I was a graduate student. And now, it really feels real.”
Sample search from Mars: Guide illustration
Click here to see how NASA and ESA will bring the rocks of Planet Mars to Earth.