The lead scientist on NASA’s Perseverance Mars rover is excited about the material stored in the rover’s sample tubes, which both fell to the surface of Mars and was contained within the rover itself as it spun around in Jezero Crater.
Examining the Mars samples collected by Perseverance, scientists say one tube appears to be filled with what the rover was looking for: evidence of past microbial life on the Red Planet.
The preliminary finding raises the need to send these Mars samples back to Earth so that these valuable collectibles from the Red Planet can be sent to laboratories for more detailed analysis.
Related: If there is life on Mars, don’t count on sample return missions to find it, scientists say
Lively question
Caltech’s Kenneth Farley, project scientist for NASA’s Perseverance Mars rover program, briefed the Extraterrestrial Materials Analysis Group (ExMAG) during a May 13-15 meeting in Houston, Texas.
Using the tag “Lefroy Bay,” Farley drew attention to this sample collected by the Perseverance rover that contained hydrated silica. Here on Earth, this mineral has the greatest potential to preserve signs of ancient life.
So a lively question arises that requires no answer: perhaps Lefroy Bay carries preserved traces of ancient life on Mars?
Paleoenvironmental conditions
“The Lefroy Bay sample and two other samples from the same unit – the ‘Margin Unit’ – are aboard Perseverance,” Farley told Space.com. “The margin unit samples contain abundant carbonate and silica, clearly indicating a dominant role of liquid water in their formation,” he said.
But whether that water was surface water in a lake or river or groundwater remains uncertain, Farley added. Both could represent an ancient (more than 3.4 billion years old), habitable Martian environment, he said.
These samples harbor phases that are very useful on Earth for creating “paleoecological” conditions, Farley noted, and they can also preserve biosignatures. “Therefore, these samples are of particular importance for returning to Earth for further study,” Farley said.
Goal: carved in stone
Perseverance is “on the verge of a really fundamental shift in the exploration of the environment in which we have been working,” Farley explained in his briefing to ExMAG. “One of the challenges we face,” he said, “this is not good terrain to drive a rover over.”
So far, the Martian machinery has traveled around 17 miles (27 kilometers) after being lowered into the area by sky crane on February 18, 2021. The robot’s goal is set in stone: “Search for signs of ancient life and collect rock samples and regolith for a possible return to Earth,” NASA explains.
But why was the 45-kilometer-wide Jezero Crater chosen as the rover’s exploration site?
Scientists believe the area was once flooded with water and was home to an ancient river delta. The expectation is that Jezero Crater will literally “spill out” about its recurring nature of Mars’ wet past. More than 3.5 billion years ago, river channels poured over the crater wall and formed a lake.
It is possible that microbial life existed in Jezero during one or more of these rainy periods. If this is true, traces of the remains of these small creatures could be found in the sediment on the lake bed or the shoreline.
Rover Challenges
As for the overall health of the Perseverance rover, Farley noted a few problems: First, the loss of wind sensors that are part of the Mars Environmental Dynamics Analyzer (MEDA), built by an international team led by Spain’s Centro de Astrobiología. “We lost most of the wind sensors. “They practically no longer work,” he reported.
The spectroscopy parts of the Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals, or SHERLOC for short, mounted on the robot arm are also challenged. This is because a lens cover no longer works properly. However, there is some preliminary work that suggests scientists may be able to restore SHERLOC’s spectroscopy capabilities. “We will learn more about this in the coming months,” Farley said.
Three Forks Depot
The rover was sent to Mars with 38 tubes that could be used for rock, regolith and even atmosphere sampling. “We are about two-thirds of the way through collecting samples,” Farley said.
The robot on duty sampled igneous rocks, mudstone, sandstone/pebble conglomerate, carbonate-silica-olivine, and Martian sand on the top and captured a hint of the Martian atmosphere.
At the start of its Mars walk, Perseverance dropped ten sealed sample tubes at a depot site called “Three Forks” in Jezero Crater. The intent is that a Mars Sample Return (MSR) mission in the future would collect sample tubes to rocket these parts of Mars to Earth.
However, this joint venture between NASA and the European Space Agency is currently undergoing a detailed review as the cost is estimated at $11 billion and the expected but unsatisfactory timeframe for carrying out such a complicated undertaking is foreseeable.
Stay on track
Farley told the ExMAG group that rover operators are working to qualify Perseverance to a cruising speed of 55 miles (90 kilometers) so it can venture into a more invigorating landscape.
“There is obviously enormous uncertainty about what the MSR will look like. We are waiting to hear what role we will play in the Perseverance mission,” Farley said. “But for now we are staying on track. We will essentially behave as we have done before, with a strong focus on sampling.”
The rover’s itinerary now includes completing tasks in an area called Bright Angel and then continuing to the crater rim, where the rover can examine fundamentally different geology, Farley added.
As we climb the rim, “we will complete the sampling quickly. The sooner we finish sampling, the sooner we can all be confident that we have done our job,” Farley said.
What happens next for Perseverance is not yet clear.
“Maybe we’ll return to the crater floor to rendezvous with MSR, maybe not. It depends on what actually happens with MSR,” Farley concluded.