NASA’s Mars rover headed for dicey landing
It’s a ‘no go-back, no retry’ encounter for Perseverance
They call it the “seven minutes of terror,” which doesn’t do justice to the weeks of anxiety, troubleshooting, second-guessing, sleepless nights — the mental cataloging of all that could go wrong and all that must go exactly right. One cataloger is Matt Wallace, deputy project manager for NASA’s Perseverance rover mission. He has a simple way of describing what the space agency expects him and his fellow engineers to do: “Land a car on Mars.”
This is one of the hardest technological feats human beings have ever attempted. The spacecraft carrying Perseverance, which launched from Earth at the end of July, is expected to arrive on Thursday at Mars at 12,000 mph — six times faster than a bullet shot from an M16 — in what amounts to a controlled collision. Somehow, that velocity has to reach zero, with the rover deposited lovingly on the surface inside a crater named Jezero.
Hitting the 4.8-mile-wide landing site targeted by NASA after a journey of 300 million miles is akin to throwing a dart from the White House and scoring a bull’s-eye in Dallas.
This is one of NASA’s most important endeavors, the first multibillion-dollar Mars mission in nine years and the initial phase of a three-mission campaign to return samples of Martian soil to Earth. The rover is poised to land just days after two other robotic spacecraft, one launched by China and the other by the United Arab Emirates, reached Mars and went into orbit.
Perseverance will do more than probe the surface: It will also test technologies that someday could be used on Mars by astronauts, including a system to convert atmospheric carbon dioxide to oxygen. NASA’s human spaceflight program aims for a return mission to the moon in coming years, but Mars remains the horizon goal.
Among seven primary scientific instruments aboard the Perseverance rover are two developed in part at Los Alamos National Laboratory.
LANL, in collaboration with the French space agency and other academic partners, invented the SuperCam, a laser mounted on the rover to study and take samples of rocks up to 25 feet away, part of the search for signs of past microbial life. SuperCam also can identify potentially harmful elements in the dust for future human missions.
The instrument, according to a LANL release, also has a microphone that can measure wind speed and direction, and can examine the speed of sound for the first time on another planet. SuperCam’s microphone is also expected to deliver the first recordings from the Martian surface.
The other scientific instrument courtesy of LANL is called SHERLOC, a device attached to the rover’s arm that uses UV laser-induced fluorescence to seek organic molecules that could represent signs of life. LANL built the device’s detector and electronics.
The lab also helped to develop the rover’s power source — a “multi-mission radioisotope thermoelectric generator,” basically a nuclear battery that employs heat from the radioactive decay of plutonium-238 to generate electricity, according to the release.
NASA describes this as an astrobiology mission. Perseverance has instruments that might detect structures consistent with prehistoric life on the Red Planet. Or those instruments might detect nothing remotely suggestive of life. Either way, NASA wants the soil samples back for study in laboratories, hoping to answer fundamental questions about life in the solar system and beyond. Finding a second data point for life would be one of the greatest discoveries in the history of science.
But, first, the engineers have to pull off the EDL — the entry, descent and landing. It is the hardest part of the mission, fraught with opportunities for what aerospace engineers call “a bad day.” The EDL requires a heat shield, a parachute, rocket thrusters and a sky crane that finally lowers the rover to the surface. All these things have to work with exquisite precision and entirely autonomously.
“We’re basically watching the spacecraft disassemble itself as it’s hurtling toward the ground,” Wallace said. “Success depends on everything going right, down to fractions of a second. There’s no go-back, no retry.”
The list of countries that have successfully landed a working, long-lasting probe on Mars remains at one — the United States. That is about to change, in all probability.
Perseverance is facing something of a traffic jam around Mars. The two spacecraft from the United Arab Emirates and China that have been hurtling toward Mars for months hit the brakes in recent days to slow themselves down enough to enter orbit around Mars. The UAE’s Hope spacecraft arrived Feb. 9, followed by China’s Tianwen-1 the next day.