In just a year and a half on Mars, NASA’s Perseverance rover has completely shaken up its mission. The agency held a briefing Thursday to discuss the highlights of the science mission so far, and it was a celebration of rock samples and the discovery of organic matter.
Organic molecules at Wildcat Ridge
A rock named Wildcat Ridge, located in an ancient river delta area in Jezero Crater, was one of the stars of the show. Percy successfully collected two samples from the mudstone rock. Wildcat Ridge is particularly intriguing because the organic molecules (called aromatics) found in it are considered a potential biosignature, which NASA describes as a substance or structure that could be evidence of past life but could also have been produced without presence of life.
The rover team emphasized that finding organic matter does not mean evidence of ancient life has been found. Organic molecules have been detected on Mars before, by the Curiosity rover in Gale Crater and also by Perseverance, which found carbon-containing molecules earlier in the mission.
Perseverance collected two core samples from Wildcat Ridge and also scraped a round patch to inspect the rock with Sherlock’s instrument.
NASA, JPL-Caltech, ASU, MSSS
The rover’s Sherlock instrument surveyed the rock. (Sherloc stands for Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals.) “In its analysis of Wildcat Ridge, the Sherloc instrument recorded the most abundant organic detections on the mission to date,” NASA said.
Scientists see familiar signs in analysis of Wildcat Ridge. “In the distant past, the sands, silts and salts that now make up the Wildcat Ridge sample were deposited under conditions where life could potentially have thrived,” said Perseverance project scientist Ken Farley. “The fact that organic matter was found in such a sedimentary rock — known for preserving fossils of ancient life here on Earth — is significant.”
Perseverance is not equipped to find definitive evidence of ancient microbial life on the red planet. “The reality is that the burden of proof for establishing life on another planet is very, very high,” Farley said during the press conference. For that, we need to examine Martian rocks up close and personal in Earth laboratories.
Sample drop
Percy currently has 12 rock samples, including the Wildcat Ridge pieces and samples from another sedimentary delta rock called Skinner Ridge. He also collected igneous rock samples earlier in the mission that show the impact of volcanic activity in the crater long ago. NASA is so happy with the diversity of samples being collected that it is considering dropping some of the full tubes on the surface soon in preparation for the future Mars Sample Return (MSR) campaign. MSR is an ambitious plan to send a lander to Mars, retrieve Percy’s samples, launch them from the surface, and bring them back to Earth for careful study. The mission is under development. If all goes as planned, these rocks could be here by 2033. The complexity and importance of the MSR means that NASA and its partners are working out ways to ensure that the samples are collected. It is hoped that Perseverance will still be in good working order by the time the MSR lander arrives and will be able to meet it and deliver personal samples. Leaving some samples on the ground so early in the mission at a cache site in the crater will give the MSR another chance to get the precious rocks on board. Percy collects paired specimens. For example, he could hold one Wildcat Ridge pipe and drop the other on the ground. “That we are weeks away from developing Perseverance’s fascinating samples and just years away from bringing them to Earth so scientists can study them in exquisite detail is truly amazing,” said NASA JPL Director Laurie Leshin. “We’re going to learn so much.”
What’s next for Percy?
As exciting as the delta was, the rover team is looking forward to future adventures beyond it. Persistence could wander to the rim of the crater, with the team looking at several possible paths for the ascent. Ingenuity’s escort helicopter is in good health and is expected to be airborne again. NASA chose Jezero Crater for exploration because of the fascinating history of water and how the rocks there could preserve evidence of ancient life if it existed during more habitable times on Mars. Sherlock scientist Sunanda Sharma likened the mission to a treasure hunt for organic life on another planet, saying the scented samples are a clue. The mystery of Mars is just beginning to unravel.
