Landing a rover on Mars is never easy. But with some perseverance, NASA finds, anything is possible.
The successful touchdown of the Mars Perseverance rover yesterday at approximately 3:55 p.m. EDT marks the Administration’s fifth rover landing—and its most technical yet—on the red planet.
Perseverance’s new home is the Jezero crater, a 28-mile-wide bowl that, billions of years ago, hosted a lake, a river delta, and potentially life. It’s a landing site that was briefly considered for Perseverance’s predecessor Curiosity, but quickly ruled out by the NASA team. “The site was considered too unsafe. And really, the terrain was way too rough,” NASA engineer Al Chen, who worked on both the Perseverance and Curiosity missions, says in a NASA video. “But now we have the ability to land at these places that we never really could go to before.”
Deltas, like the one at Jezero, the Perseverance team believes, have a high likelihood of once hosting life. After all, the team posits that Jezero’s ancient river delta was once rich in mineral sediments and, as recently as 3 billion years ago, fed into an 820-foot-deep lake. But deltas aren’t just great at hosting life, explains Katie Stack Morgan, a deputy project scientist for the Mars 2020 mission: “They’re also great places for preserving past life,” she says in a NASA video.
“We think that Mars was habitable about 4 billion years ago,” Chen adds. “So the question is not just where was that life, but also, where could it be preserved for four more billion years for us to find it.”
But for the quest for biosignatures (organic matter trapped in Martian rocks that could indicate tiny microbes once flourished in the planet’s ancient watery habitats) to begin, Perseverance first had to land on Mars.
At approximately 3:38 p.m. EDT on Thursday, the spacecraft ferrying Perseverance and its companion Ingenuity—the first-ever space helicopter—began its entry into the Martian atmosphere. So began its 17-minute descent and landing.
Hovering 118 miles above Mars’ surface, the craft burned through the atmosphere at more than 17,060 feet per second. Once the craft “feels” enough atmosphere around it, it’ll begin controlling its path, said the Guidance, Navigation, and Controls Operations Lead for the Mars 2020 mission Swati Mohan on NASA Live Television. As the craft slowed down, a hush fell upon the team at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif., their eyes glued to the live feed displayed on their computer screens in front of them.
The seven minutes of terror—a phrase used by Mars aficionados to describe the most critical phase of a rover’s entry, descent, and landing—had begun.
The entry and landing is all about “getting the top of the vehicle through the atmosphere and down to the bottom safely. We hit the atmosphere, you know, going 12—13,000 miles per hour. We have to deploy a supersonic parachute,” Chen says. “I worked on Curiosity for 10 years, so this is a very familiar feeling,” Chen, who helped ferry that rover safely to Mars’ Gale Crater in 2012, adds. But “I think I was really too young the first time to realize what was at stake.”
As it made its way through the Martian atmosphere, Perseverance performed bank reversals, crucial steps to control its distance to its landing target. The rover, nicknamed “Percy,” then passed through its maximum point of deceleration.
“Yes, yes, yes,” whispered a team member back at JPL.
One mile above the red planet’s surface and traveling at 2,237 mph, Perseverance aligned with its landing target below. It slowed to 1,230.3 mph, performed a telemetry lock on its landing target, and initiated a maneuver that gave its radar a better glimpse of the Martian surface.
Applause erupted from the team at JPL.
Still at supersonic speed, Percy’s parachute deployed.
It continued its descent, now slowing down to subsonic speeds—those below the sound barrier—offering its radar an even better look at the rocky terrain below. The entry capsule fully separated from the rover and its “jetpack,” equipped with retrorockets (small auxiliary rockets fired in the direction of travel to slow a craft down). As it completed its terrain navigation, pinpointing a landing site, Percy reached a constant velocity and, starting at about 65 feet above the Martian surface, the craft attached to the rover performed a “sky crane” maneuver, in which it lowered the rover to the ground.
At 3:55 p.m. EDT, the team receives the signal they’ve been waiting for: Perseverance has touched down. Cheers and claps erupt from the control room at JPL. Some team members share COVID-19-friendly elbow bumps.
“Oh my god. Oh.” “Whew; we got it.” “It’s so surreal,” they say.
Perseverance’s first assignment was relatively straightforward: snap some pictures of its new home. But in the following weeks, its work looking for life will begin.
“What we’re trying to do is drive around the surface of this unknown planet to try to find out if, at some point, there was life on the surface of Mars,” aerospace engineer Diana Trujillo, who works with the robotic arms responsible for collecting Martian soil samples, says in a NASA video.
We have two very interesting instruments on Perseverance’s robotic arm, Trujillo explains. To collect and analyze samples, the rover will drill into the soil and its arm will place the instruments into the resulting holes. This will help us understand what the terrain is composed of and whether there is “some traceability of life,” she says.
But the most thorough analyses, Morgan adds, will happen back on Earth. Morgan, who grew up with a love for geology, other worlds, and hiking in national parks, is interested in what each individual sand grain has to tell us about Mars and its evolution. “We have capabilities in laboratories here on Earth that we can’t fit on a compact instrument on a rover,” she explains.
The Perseverance mission will also test technology designed to produce oxygen from the Martian atmosphere. Researchers hope that the gas could be used for fuel, or for humans to breathe, on future missions, like NASA Artemis.
The Mars helicopter Ingenuity, though simply a demonstration that such a craft can fly over another planet for the first time, also has its work cut out for it. “We have a series of major milestones between now and Ingenuity’s [first] flight,” Ingenuity’s project manager MiMi Aung said on Thursday during the descent on NASA Live Television. “Surviving the first frigid night on Mars will be a major milestone.” And when Ingenuity does take flight, it aims to take the first-ever color photos of Mars from an aerial standpoint. “They’ll just be icing on the cake,” Aung said.
Already, a feeling of pride and success—and, well, perseverance—is evident among the Mars 2020 researchers.
“I feel like such a lucky person to be working on this,” Trujillo says. “I was born and raised in Colombia. There was a lot of violence going on in my country, so for me, looking up at the sky and looking at the stars was my safe place.”
Tune in or stream “Looking for Life on Mars” on Wednesday, February 24 at 9/8c on PBS.