NASA just now successfully landed Perseverance, its largest and heaviest rover yet, on the surface of Mars in the Jezero Crater. The machine will conduct the ambitious mission to finding ancient microbial life on another planet.
“Touchdown confirmed. Perseverance has touched down on Mars,” Swati Mohan, Navigation and Control Operations Lead of the Mars 2020 mission, said moments ago, just before mission control erupted in applause.
Perseverance’s first image beamed back from Mars upon landing, and inset: an illustration of it parachuting down to the surface. Click to see larger version of first photo
After cruising though space for a little over seven months, Perseverance entered its entry, descent, and landing stage, also fondly known at NASA as the seven minutes of terror.
“That’s the time it takes for the vehicle to make it from the top of the atmosphere on Mars down to its surface,” Michelle Munk, a Systems Capability Lead for Entry, Descent, and Landing at NASA, told The Register. “It basically has to go from about 12,000 miles per hour (~5364 meters per second) to zero in a short period of time. Many things can go wrong during this process.”
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The aeroshell, a protective casing holding the rover, ripped through the Martian atmosphere at about 5,300 meters per second when it was 120 kilometers from the Martian surface. It was eventually slowed down by atmospheric friction, and once it reached a steady pace of about 550 meters per second, it deployed its giant supersonic parachute to decelerate the vehicle even more as it continued to descend 15 kilometers fron Mars.
Next, the heat shield was ejected giving some of Perseverance’s onboard cameras and radar a clear view of the Martian ground getting closer and closer. Armed with a new type of landing technology, known as Terrain Relative Navigation, the rover could estimate its position relative to the ground and steer itself away from hazardous areas.
Perseverance used radar to measure its distance, and snapped a series of images of its local area. Thanks to the Mars Reconnaisance Orbiter, its landing site, Jezero Crater, has been mapped and Perseverance can compare its images with the map stored on its computers to find the best landing site. “Landing in this terrain is very challenging, you’re right next to 100-meter high-cliffs,” Munk said.
Once it was close to an ideal flat landing site, it jettisoned off its parachute and shed its ablative shell. At this point, its descent stage, a robotic jet pack-like structure holding the rover with wires, ignited a series of rockets to steer Perseverance onto the surface. The vehicle was then safely lowered using a sky crane maneuver twenty meters above the ground. The wires were cut and the descent stage flew off to crash a fae distance away.
You can watch a simulation of the seven minutes of terror in a video below – or replay NASA’s livestream of the landing here.
Landing a robotic rover or spacecraft is arguably one of the most challenging parts in space exploration: About 50 per cent of all landing attempts made by any space agency have ended in failure, according to NASA [PDF]. Given that it takes about 11 minutes and 22 seconds to communicate a message between Earth and Mars on current orbits, NASA cannot monitor the landing process, by the time staff started receiving any data, Perseverance was already on the ground.
Mission control members did nothing and just sat back, held their breath, and crossed their fingers. “With such a successful track record, we make it look easy some time, but it’s never easy. We can’t ever take it for granted. During the time we wait to hear back from the rover, all we can do is hope that we have thought of every scenario, and reduced every possible risk,” Munk said.
Thankfully, mission control managed to receive confirmation of the rover’s status as it beamed its signals to the Mars Reconnaisance Orbiter to send to Earth.
Now that the landing has been successful, it means that the Terrain Relative Navigation system has passed its latest test. “It will be used for the upcoming lunar landing missions in the Artemis programme. I fully expect it will be used on everything from small robotic missions up to human-scale missions to Mars. It’s a building block for precision landing technologies. It will lower the risk for crewed missions since it can perform hazard testing. The next step is trying to see if we can use a laser to construct a real-time map without having to rely on old maps so that spacecraft may one day land in undiscovered areas,” said Munk.
Persevering in the search for alien life
As the world learned to adapt and work during the current coronavirus pandemic, scientists and engineers at NASA tried their best to continue as normal. The Mars 2020 mission has been more than eight years in the making after all, and nothing was going to get in the way – not even a highly contagious respiratory disease spreading around the world.
NASA pushed back its James Webb Space Telescope by seven months and temporarily paused testing of its SLS moon rocket, but continued to work on Perseverance to meet its summer launch deadline last year.
Although it was delayed twice, it finally managed to fly off into space aboard an Atlas V rocket from Cape Canaveral at the end of July during a critical time window, when the distance between Earth and Mars was at its shortest.
Just four months after NASA’s previous rover Curiosity landed, in December 2012 it announced it was going to invest billions of dollars into another trundlebot that promised to be bigger and better.
The end result: A 1,025-kilogram, nuclear energy-powered, SUV-sized six-wheeled robot car carrying a tiny, foldable helicopter strapped to its belly.
Built using already-designed components from Curiosity, the new rover is pretty similar to its predecessor. It also comes armed with numerous cameras to image Martian terrain, spectrometers to detect chemical compounds, sensors to monitor weather, and a robotic arm.
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But Perseverance also has a few new tricks up its sleeve, including an x-ray laser to zap rock samples, microphones to record Martian sounds, an electrolysis machine to produce oxygen from carbon dioxide, and a drill to cut off chalk-sized regolith to be bottled in capsules that will be collected later and flown back to terra firma in a future mission (dependent on funding). All in all, the vehicle has seven main instruments alongside two primary radiation-hardened RAD750 computers.
The robot’s kit allows it to be a geologist on wheels. Peserverance will be hunting for signs that ancient, simple microbes once lived in the shallow waters of what is now Jezero crater some 3.5 billion years ago. For example, on Earth there are stromatolites – rocky structures built from cyanobacteria secreting compounds that trap sediments in multiple layers. It may be possible that there are similar stromatolite-like materials hidden in the crooks and crannies of Jezero crater.
Perseverance will use its various tools to analyze a sample’s chemical composition and structure to find any material that might contain organic compounds or minerals formed in water. The most promising samples will be drilled and stored into capsules for future spacecraft to collect.
Scientists probably won’t be able to confirm whether alien life once existed on Mars, however, until they can get their hands on the samples. “We have strong evidence that Jezero Crater once had the ingredients for life. Even if we conclude after returned sample analysis that the lake was uninhabited, we will have learned something important about the reach of life in the cosmos,” said Ken Williford, deputy project scientist for the Mars 2020 Perseverance rover mission at JPL.
“Whether or not Mars was ever a living planet, it’s essential to understand how rocky planets like ours form and evolve. Why did our own planet remain hospitable as Mars became a desolate wasteland?.”
What’s Perseverance up to now?
Mission control will establish that all instruments are working as normal before the rover begins exploring Jezero crater. Soon after, it’ll unleash its helicopter pal Ingenuity.
Ingenuity will be the first aircraft to fly on another planet. Designed to last about 30 Martian sols, it weighs about two kilograms and is 1.2 meters wide and carries two computers. The drone is more of a experiment than a piece of equipment for scientific discovery; engineers want to test its ability to fly autonomously. It can travel to distances stretching to almost 300 meters and hover three to 4.5 meters from the ground in 90 seconds.
Now that Perseverance is well and alive on Mars, it’ll begin its mission to find signs that Mars once supported life.
“To quote Carl Sagan,” said Gentry Lee, chief engineer for the Planetary Science Directorate at NASA’s Jet Propulsion Laboratory,
“‘If we see a hedgehog staring in the camera, we would know there’s current and certainly ancient life on Mars, but based on our past experiences, such an event is extremely unlikely. Extraordinary claims require extraordinary evidence, and the discovery that life existed elsewhere in the universe would certainly be extraordinary.’”
“We have been waiting for this mission for such a long time,” Munk told us. “Ever since I got to NASA over 30 years ago now, scientists have been wanting to bring a sample back from Mars. I’m so excited to finally embark on this very ambitious mission.” ®