NASA rover Perseverance successfully lands on Mars
By Joel Achenbach, Sarah Kaplan and Ben Guarino
Feb. 18, 2021 at 9:00 p.m. GMT
washingtonpost.com
NASA’s rover Perseverance landed safely Thursday on Mars to begin an ambitious mission to search for signs of past Martian life and obtain samples of soil and rock that could someday be hauled back to Earth for study in laboratories.
Perseverance used a newly developed autonomous guidance system to avoid the hazardous terrain in an ancient lake bed known as Jezero Crater. The touch down followed the “seven minutes of terror” — in homage to the emotional state of engineers rooting for success — when the spacecraft carrying the rover shed pieces of hardware, endured heating as it entered the Martian atmosphere at 12,000 mph, deployed a parachute while still going nearly twice the speed of sound and then used rocket thrusters and a system known as a sky crane to lower the rover to the surface.
Perseverance will snap two photos minutes after landing, from cameras on the front and back of the robot. Those cameras have lenses shielded by dust covers. NASA expects a pair of somewhat fuzzy, low-resolution images to be transmitted first, within the day. Higher-resolution images from the rover might not be available until Friday morning.
The landing on rough terrain is the most hazardous phase of the multibillion-dollar mission. The entry, descent and landing must be accomplished entirely autonomously. Mars is too far from Earth to permit technicians to joystick the landing; a signal between the spacecraft and Pasadena takes 11 minutes at the speed of light.
NASA’s Mars rover, Perseverance, aims for dicey landing to search for ancient life
“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 spacecraft began a six-month journey through interplanetary space at the end of July. The spacecraft is loaded with navigation software to guide it onto terrain featuring 200-foot cliffs, gullies, boulders and sand-filled craters that could potentially immobilize it.
“She won’t necessarily find the most welcoming site we’ve even been to. It’s got craters, it’s got rock fields, it’s got sand dunes,” Wallace said.
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.
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 areais 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.”
“If we could find something like that on Mars, that would be the holy grail for astrobiology,” said Purdue University planetary scientist Briony Horgan, a member of Perseverance rover’s science team. Horgan has led satellite surveys of the landing site that showed it is rich with the kinds of molecules known to help preserve the signatures of living organisms.
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.”
Christian Davenport contributed to this report.
Headshot of Joel Achenbach
Joel Achenbach
Joel Achenbach covers science and politics for the National desk. He has been a staff writer for The Post since 1990. Follow
Headshot of Sarah Kaplan
Sarah Kaplan
Sarah Kaplan is a climate reporter covering humanity's response to a warming world. She previously reported on Earth science and the universe. Follow
Headshot of Ben Guarino
Ben Guarino
Ben Guarino is a reporter for The Washington Post’s Science section. He joined The Post in 2016. Foll
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