NASA’s Mars rover, Perseverance, aims for dicey landing to search for ancient life
Seven minutes of terror: “Success depends on everything going right, down to fractions of a second” (WaPo)

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 cataloguing 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 miles per hour — 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.