It’s been a year since a nuclear-powered, one-armed, six-wheeled robot sped through the Martian atmosphere at a blistering 12,000 miles per hour, and a supersonic parachute slowed it down until a rocket-powered “jetpack” can fire its engines, then gently lower it to the surface.
NASA’s Perseverance rover was too far away for engineers on Earth to control in real time, which meant the spacecraft had to perform this daredevil maneuver itself. All the robot’s masters on Earth could do was wait for confirmation that it had landed safely.
“It’s a jaw-dropping experience,” said Perseverance Deputy Project Manager Rick Welch. “There is no doubt about it.”
As spectacular as the February 18, 2021 touchdown was, the milestones the car-sized rover has achieved in the year since then could one day prove far more significant.
Perseverance is on the hunt for evidence of microbes that may have once lived on the Red Planet – a first for a NASA robot. It begins a new chapter in Mars exploration: one that not only searches for ancient signs of microbial Martians, but lays the groundwork for sending rock and dirt samples from Mars to Earth.
One of the main goals of the mission is to collect rock and soil samples and store them on the surface of Mars so that a future mission can pick them up and bring them back to Earth for study. The $2.7 billion rover is equipped with a suite of scientific instruments, including a blasting laser, cameras and spectrometers.
But a robot geologist – even as advanced as Perseverance – can’t do much. Scientists really hope to bring pieces of the planet back to their labs.
“That’s really the main reason for wanting to collect and return samples,” says Welch. “We could really understand Mars better by getting these samples here on Earth.”
A story of the search for life on Mars
Perseverance is NASA’s first rover sent to search for signs of ancient life. Nearly half a century ago, NASA sent a pair of landers to Mars, marking the first US mission to successfully land on the planet. The Viking mission, launched in 1975, aimed to search for current life on Mars – and turned out to be empty.
“The Viking Landers results were ambiguous and taught us that we needed to better understand the surface of Mars and potential habitats on Mars,” said Mary Voytek, NASA senior scientist for astrobiology.
Follow-up missions from orbiters, landers and rovers have sought to see if Mars was even habitable to begin with. They focused on finding ancient water signs first – a key to life as we know it here on Earth. Rovers like Spirit and Opportunity, launched in 2003, and Curiosity, launched in 2011, provided the foundation for Perseverance to begin searching for ancient microbes in rocks and dirt on Mars.
Perseverance searches for an area on Mars known as the Jezero Crater. Scientists believe it could be an ancient lake fed by a flow of Martian rivers. Over the next few months, the rover heads straight for a river delta at the crater rim.
“Life as we know it requires habitable environments,” says Amy Williams, a University of Florida astrobiologist and mission scientist. The hypothesis is that life on Mars would need water as a universal solvent, much like life here on Earth. “Finding environments where we know the water has flowed is one of the big boxes that we can check off that this is a really great place for us to do this investigation.”
Much like river deltas here on Earth, scientists expect to find layers and layers of rich geological history trapped in the sediments – a prime place to drill for samples that may have trapped evidence of past Martian life.
Confirming ancient life on another planet would be an extraordinary discovery, experts say, that will require extraordinary evidence.
“Sample return is the only way for me, and I’m sure many other astrobiologists, would be truly convinced that we had found evidence of life on Mars,” Williams said.
The rover is equipped with drills and sampling tubes and has already started collecting pieces of Martian rock. In its first year, it collected and stored 6 samples, with the ability to collect up to 40.
NASA and the European Space Agency are working together to develop a mission to collect these samples, launch them from the surface of Mars, and return them safely to Earth.
“It’s an incredibly complex mission,” says Lori Glaze, director of NASA’s planetary science division, of the technical and financial challenges ahead.
The agency has awarded Lockheed Martin a contract to develop the Mars Ascent Vehicle, which will be the first rocket to launch a payload from another planet. But other elements of the mission’s architecture are still under construction.
“We’re still pretty early in development, but we’re working to get those samples back here as soon as possible,” says Glaze.
If all goes well, scientists could get their hands on Martian rocks in 2031.
The little chopper that could
While scientists wait for Perseverance to collect Mars samples, the mission is breaking new ground in other ways. A small helicopter stowed on the belly of the rover made 19 successful flights on the surface of Mars. What started as a proof of concept – that engineers could even design a plane capable of flying through Mars’ thin atmosphere – is now helping the rover spot new places to explore.
“It’s really a game-changer,” Glaze says. “The helicopter is able to fly over areas that are too rugged for the rover to traverse. We are able to see these high-resolution images in areas that the rover cannot reach and consider future exploration.”
Ingenuity helps Perseverance navigate to this key target: a geologically rich river delta where scientists hope to uncover layers of Martian history written in rocks by ancient water. Over the next few months, Perseverance will make its way there – with Ingenuity jumping ahead to blaze the trail.
But all good things must end. Although it hasn’t shown any signs of slowing down yet, the parts of the small plane will eventually give way. “I think [the team] will miss him when he’s gone,” Glaze says.
The way to go
The rover also helps plan future human missions to Mars, such as taking fabric samples that could one day be used for suits for astronauts bound for Mars and exposing them to the planet’s hostile atmosphere. Another experiment called MOXIE works to convert this atmosphere into oxygen that could potentially be used as fuel or for life support, pure enough to breathe.
As it makes its way to the sediment-rich river delta of Jezero Crater, Perseverance sends back stunning images of its new home on Mars.
“We’ve started to get some early images, just from where we are right now, of the valley,” says Briony Horgan, planetary scientist at Purdue University and mission scientists. “It’s really like Monument Valley on Mars. It’s fantastic.”
Perseverance puts a lot of ground under its six wheels thanks to tough new tires and a self-contained computer. The rover drives pretty much at lightning speeds – at least for a robot.
“We can walk about 200 yards a day,” or about 650 feet, Horgan says. “That’s pretty good speed, especially considering it’s a robot moving 150 million miles.”
But the state-of-the-art rover, which has already covered more than two miles, will still have a long way to go to catch up with its predecessors. Curiosity traveled nearly 17 miles across the Martian surface, while Opportunity traveled more than 28 miles before reaching its final home: Perseverance Valley.
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