Editor's note: NASA's Perseverance rover successfully touched down on Mars on Feb. 18. Read the full story here.
The landing of NASA's next Mars rover is now just days away.
The car-size Perseverance rover, the centerpiece of NASA's $2.7 billion Mars 2020 mission, will hunt for signs of ancient life, collect and cache samples for future return to Earth and help demonstrate a variety of new exploration technologies, among other tasks.
But before it can get started on any of that groundbreaking work, Perseverance must ace its touchdown inside Mars' Jezero Crater on Feb. 18. There's no guarantee that the rover will survive this harrowing ordeal; over the years, just 40% of all Mars surface missions have landed successfully.
That depressing figure is skewed by a lot of failures in the first few decades of the Space Age, however. NASA's recent Red Planet track record is quite encouraging (knock on wood), and Mars 2020 will employ a proven landing strategy — the "sky crane" technique used successfully by its predecessor, the Curiosity rover, which touched down in August 2012 and remains active today.
Here's a brief rundown of the Mars 2020 mission and its upcoming entry, descent and landing (EDL) operations to get you ready for the big day.
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What is the Mars rover Perseverance mission?
Curiosity has been assessing the habitability of ancient Mars and investigating the planet's long-ago transition from relatively warm and wet to extremely cold and dry. The Mars 2020 mission, which launched on July 30, 2020, will take the next step, actively hunting for signs of ancient Red Planet life. No surface mission has ever done this, though NASA's twin Viking landers did look for extant Mars life after they touched down in 1976.
Perseverance will also help bring the Mars life hunt down to Earth. The rover will collect and store several dozen samples, which a joint NASA-European Space Agency campaign will haul to our planet as early as 2031. Once the pristine Mars material is on the ground, scientists in labs around the world can scrutinize it using far more powerful and precise equipment than a single rover can carry to the Red Planet.
Mars 2020 also has a big technology-demonstration component. For example, a tiny helicopter named Ingenuity is flying to the Red Planet on Perseverance's belly. In the early days of the Mars 2020 mission, which is scheduled to last at least one Mars year (about 687 Earth days), Ingenuity will make a few test flights, trying to become the first rotorcraft ever to fly on a world beyond Earth. Success could open Mars to extensive aerial exploration in the future, NASA officials have said.
The 2,260-lb. (1,025 kilograms) Perseverance is also carrying an instrument called MOXIE, which is short for "Mars Oxygen In-Situ Resource Utilization Experiment." (And ISRU stands for "in situ resource utilization.") MOXIE will generate oxygen from the thin, carbon dioxide-dominated Martian atmosphere, showcasing tech that, if scaled up, could help humanity get a foothold on the Red Planet, NASA officials have said.
You can learn much more about Perseverance and its science goals on our Mars 2020 reference page.
Where is Perseverance landing?
NASA announced in November 2018 that Perseverance will explore Jezero Crater, a 28-mile-wide (45 kilometers) hole in the ground about 18 degrees north of the Martian equator.
More than 3.5 billion years ago, Jezero hosted a lake about the size of Lake Tahoe, as well as an associated river delta. And NASA's Mars Reconnaissance Orbiter has spotted clay minerals, which form in the presence of liquid water, on the crater's floor.
"On Earth, scientists have found such clays in the Mississippi River delta, where microbial life has been found embedded in the rock itself," agency officials wrote in a description of Jezero. "This makes Jezero Crater a great place to fulfill the Mars 2020 mission's science goal of studying a potentially habitable environment that may still preserve signs of past life."
And in case you were wondering (or hoping): a meetup between Perseverance and Curiosity isn't going to happen. Jezero is about 2,300 miles (3,700 km) from Gale Crater, which Curiosity has been exploring since 2012.
How and when will Perseverance land?
Speaking of Curiosity: The older mission provided a template for Mars 2020 in a number of ways. Perseverance's body is very similar to that of Curiosity, for example, and the two missions share the same dramatic "seven minutes of terror" EDL strategy.
As Mars 2020 nears the Red Planet on the afternoon of Feb. 18, the spacecraft will shed its "cruise stage," the part that housed the solar panels, fuel tanks and radios needed for its long interplanetary journey. Ten minutes after that milestone, Mars 2020 will hit the Red Planet's atmosphere at a speed of almost 12,500 mph (20,000 kph), and the terror countdown clock will start ticking.
Though Mars' atmosphere is just 1% as thick as Earth's, it's substantial enough to slow Mars 2020 down dramatically via drag. But that service comes with a cost: frictional heating, which will generate temperatures as high as 2,370 degrees Fahrenheit (1,300 degrees Celsius) on the surface of the spacecraft's heat shield. Perseverance itself won't experience such extremes, of course; it will be about room temperature inside Mars 2020's protective aeroshell, which consists of the heat shield and a piece called the back shell.
Mars 2020 will deploy its 70.5-foot-wide (21.5 m) supersonic parachute about four minutes after atmospheric entry, when the spacecraft has slowed to a much more manageable 940 mph (1,512 kph). To get the timing of deployment just right, Mars 2020 will use a new technology called Range Trigger, which Curiosity did not have.
Twenty seconds after the supersonic chute makes its appearance, Mars 2020 will jettison its heat shield, exposing Perseverance to the fast-rushing Red Planet air. The rover will then start documenting its descent in great detail, snapping photos of the Martian surface and using radar to figure out its altitude.
Those photos will be employed by another new technology Mars 2020 will showcase — Terrain-Relative Navigation, which involves the comparison of descent imagery with an onboard map.
"Mission team members have mapped in advance the safest areas of the landing zone," NASA officials wrote in a detailed summary of the Mars 2020 EDL sequence. "If Perseverance can tell that it’s headed for more hazardous terrain, it picks the safest spot it can reach and gets ready for the next dramatic step."
The parachute will slow Mars 2020 down to about 200 mph (320 kph) — still far too fast for a safe landing. So, about six minutes into the seven minutes of terror, at an altitude of 6,900 feet (2,100 m), the back shell and attached parachute will fall away, and the mission's "sky crane" descent stage will kick into gear.
The sky crane's eight thrusters will fire downward, eventually slowing Mars 2020 to just 1.7 mph (2.7 km/h). Then, at an altitude of 65 feet (20 m), the crane will lower Perseverance toward the ground on long cables. After the rover touches down safely, it will cut the cables, and the descent stage will fly off to crash-land intentionally a safe distance away.
That touchdown will occur at 3:55 p.m. EST (2055 GMT) on Feb. 18, if all goes according to plan.
Yes, this sounds a little crazy, especially considering that Mars 2020 will have to do everything on its own, without any help from mission control. (On Feb. 18, it will take more than 11 minutes for a signal to travel from Earth to Mars — longer than the entire EDL sequence.) But it worked for Curiosity back in 2012.
And we'll be able to follow all the EDL action in (nearly) real time: NASA will provide coverage of the big event, starting at 2:15 p.m. EST (1715 GMT) on Feb. 18. You can watch it live here at Space.com, courtesy of NASA, or directly via the space agency.
And in the heady days after a successful landing (knock on wood, again), we could get an unprecedented treat — high-quality video and audio of Mars 2020's touchdown sequence, thanks to HD EDL cameras and an associated microphone.
Visit Space.com on Feb. 18 for complete coverage of the Mars rover Perseverance landing.
Mike Wall is the author of "Out There" (Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook.