It has been a long journey for Perseverance, NASA’s latest Mars rover, which landed safely on the red planet at 3:55 p.m
“I’m safe on Mars,” the rover announced on Twitter upon its arrival. “Perseverance will get you anywhere.”
Perseverance, a six-wheeled, SUV-size vehicle with the most sophisticated robotic astrobiology lab ever launched and an experimental aerial drone aboard, is at the heart of the Mars 2020 mission. It blasted off in July on a 293 million-mile journey. After landing, it immediately got to work, taking a photo of its “forever home.”
The rover is starting its mission, exploring an ancient crater lake bed for signs of past life or in pieces strewn across the Martian landscape. The landing site is Jezero crater, where scientists think a lake was 3.5 billion years ago. If microbes were in the lake, they might have left signatures in the rocks in the crater that the rover can detect.
Seven minutes of terror
Success hinged on a nail-biting “seven minutes of terror”: an entry, descent and landing, or EDL, sequence that was completed flawlessly and without intervention from Earth-bound engineers. Because Mars is so far away, it takes 11 minutes for signals to reach NASA’s Jet Propulsion Laboratory in Southern California, where the mission is managed. This meant that by the time engineers got a message from the spacecraft that EDL had begun, Perseverance was already on the ground — intact.
The atmosphere of Mars is a tiny fraction of Earth’s — too thin to offer much in the way of a brake for a spacecraft on a speeding descent, but thick enough to burn up the craft if something goes wrong. Many previous soft landing attempts on the planet have failed.
“Mars is hard, and we never take success for granted,” Thomas Zurbuchen, NASA’s associate administrator for science, said at a recent online media briefing.
The landing sequence for Perseverance was essentially the same high-wire act that a previous rover, Curiosity, used to land in 2012. But for their latest performance, scientists chose a more challenging spot on which to set down. Jezero crater on the western edge of Isidis Planitia is a rougher patch. Unlike Curiosity, Perseverance used something called terrain relative navigation to find a good spot and steer itself in for a touchdown.
