Cheers, clapping and fist-pumps erupted in the control room, which was half-empty because of the coronavirus pandemic. Someone shouted: “TRN, TRN,” referring to the new “terrain relative navigation” system that enabled Perseverance’s picture-perfect touchdown.
The vehicle carrying Perseverance entered the Martian atmosphere at 12,000 mph, used a heat shield to avoid burning up, then deployed a parachute while still going nearly twice the speed of sound. Finally, the craft used rocket thrusters to slow down further and then a system known as a sky crane to lower the rover the final distance to the surface.
“Perseverance really has to fight her way down to the surface on her own,” deputy project manager Matt Wallace said at a Wednesday news briefing.
The terrain “is full of stuff the scientists want to see and I don’t want to land on,” said Allen Chen, the head of the entry, descent and landing team.
The messages confirming that the lander is safe arrived via the Mars Reconnaissance Orbiter, a NASA satellite in position above the landing site.
With the rover safely deposited at its landing site, the sky crane flew away and crash-landed elsewhere on the Martian surface. Perseverance will run through a series of self-checkups to make sure its tools survived the jarring descent. Then, the robot can get to work.
Its first task was to take pictures of its own wheels on the Martian surface. NASA should receive these low-resolution images within hours of landing. By Friday, the agency expects to get better quality images of the spacecraft and its surroundings.
This begins the rover’s “commissioning” phase, when engineers examine every inch of the spacecraft’s machinery to make sure it is ready for the mission. The rover will practice driving, test its robotic arm, and update its software.
Roughly 30 Martian days (or “sols”) later, Perseverance will drive to a flat area that can serve as the flight pad for Ingenuity, a tiny solar powered helicopter. NASA will take another 30 sols to fly Ingenuity around the area, testing out the never-before-used autonomous flight technology.
Typically, Mars landings are cause for great pomp and circumstance at the Jet Propulsion Laboratory. The Pasadena campus swarms with scientists, journalists and schoolchildren. Huge projectors show a live steam from mission control. A tradition dating to the 1960s demands that a jar of peanuts be on hand at the space flight operations facility — supposedly the snack brings good luck.
Thursday’s events were more subdued, with only a minimal crew of ground controllers on site in Pasadena for the landing.
It’s yet another way the coronavirus pandemic has imposed constraints on an already complex project. Most of the engineers on the mission have been working from home since last spring. Now, they will switch to “Mars time” — organizing their lives according to the Red Planet’s 24-hour, 37-minute day. Though NASA veterans are used to their schedules slowly drifting out of sync with the rest of the world, they’ve never had to do it while working at their kitchen tables while their kids attend remote school.
But they’re doing what it takes — and keeping up traditions. On Wednesday, Los Alamos National Laboratory scientist Roberta Beal — an engineer for one of Perseverance’s two cameras — tweeted a picture of a jar of Planters peanuts perched atop her laptop in her living room.
“#I’mReady,” she said.
And fans of the mission are finding new, socially distant ways to celebrate. In Switzerland, where Zurbuchen grew up and where the rover’s motors were produced, artist Gerry Hofstetter projected images of the rover, Mars and the NASA logo onto an Alpine mountaintop.
Though led by NASA, the mission is an international endeavor. The Perseverance rover’s instruments are operated by scientists in three countries, and the Mars Sample Return program is a partnership with the European Space Agency.
The most desirable landing area is a narrow band of flat terrain that lies along the cliffs that delineate the elevated remnants of a river delta — all within Jezero Crater. The river delta is considered one of the best places on Mars to search for signs of ancient life.
Today, the crater is a bleak expanse of rock canyons and windswept sand. With no magnetic field to protect it, the planet’s surface is bombarded by solar radiation. The air is thin and mostly carbon dioxide. Nighttime temperatures plunge to minus-100 degrees Fahrenheit. It is hardly a hospitable environment.
But roughly 4 billion years ago, Mars looked a lot like ancient Earth. It boasted volcanic activity, a thick atmosphere and temperatures balmy enough to maintain liquid water on its surface.
In those days, Jezero Crater contained a vast lake. The surrounding canyons were carved by mighty rivers. The feature Perseverance is scheduled to inspect was a delta, where sediments from the surrounding watershed accumulated in layers of mud. On Earth, such sediments have preserved evidence of ancient life in the form of fossilized mats of microscopic pond scum called “stromatolites.”
Perseverance is armed with a battery of instruments designed to detect biosignatures. Two cameras will photograph the landscape and zoom in on tiny structures. A sensor will use X-rays to measure the chemical makeup of rocks while a machine mounted on the robot’s arm deploys lasers to detect organic molecules and other potential biosignatures. Ground-penetrating radar will map the subsurface, and a Martian weather station will take in data about temperature, wind and clouds of dust.
Many of these are more advanced versions of the instruments on the Curiosity rover, which has been exploring a spot far to the east of Jezero since 2012.
But Perseverance is the first NASA rover with the capacity to collect samples of soil and rock and cache them on the Martian surface. If and when the space agency is able to launch follow-up missions, those spacecraft will retrieve Perseverance’s samples and bring them back to Earth, where they can be analyzed with even more sophisticated tools in the world’s top labs.
“Finding a sample suite that is worth bringing back is really important,” said Ken Farley, project scientist for the mission. “What’s at stake is the ability to really make the first step in answering the question of whether life exists elsewhere.”
“Astrobiologists have been dreaming about this mission for decades,” said Mary Voytek, who directs NASA’s astrobiology program. Microbiologists like her have found life on Earth virtually wherever they’ve looked. Perseverance will play the role of robotic microbiologist on Mars.
It is unlikely images alone will be considered definitive proof of ancient life. Nor is it possible to miniaturize all the equipment necessary for the most detailed examinations of Martian samples. That’s why Perseverance is part of a broader project to gather samples of Mars that can eventually be returned to Earth.
There are dozens of sterilized tubes, designed to house chalk-size samples, tucked within the belly of the Perseverance robot. The rover will drill into Mars, secure rock and mineral samples in the tubes, seal the tubes and cache them for a future mission to retrieve.
A follow-up robotic lander assigned to retrieve the samples must descend to within 100 yards of where Perseverance deposits the sample cache, Braun, the sample return program manager, said Wednesday. The retriever will, in turn, hand off samples to a cargo spacecraft in orbit over Mars. This will be the largest craft ever sent to the Red Planet, in part because it will have to carry enough propellant for a return trip.
Some of the scientists who will study those samples in the 2030s, in a facility that has not yet been built, may currently be students — or even children, said Elisabeth Hausrath, a University of Nevada Las Vegas astrobiologist who is assigned to represent the interests of those future scientists.
Detecting undisputed evidence of life in Martian rocks would be a spectacular scientific discovery — perhaps the most important humanity has ever made. It would suggest that still more life could exist somewhere else.
The discovery might also remind humanity that life is not indestructible. If a changed environment is what doomed organisms on Mars, it could happen here, too.
“These types of discoveries have the ability to affect people to their core,” said Kathryn Stack Morgan, deputy project scientist for the mission. “It becomes something you have to confront about yourself and your species and your place in the universe.”
