About eight and a half years ago, I stayed up until well after midnight to watch Curiosity make Marsfall. At the time, all eyes were glued to what is euphemistically referred to as the “seven minutes of terror.” It took Curiosity and will take Perseverance approximately that long to descend from the top of the Martian atmosphere to the ground below. It takes 11 minutes for a signal from Mars to reach Earth, which means the entire descent will be over before we receive the first signals it’s begun.
“The Perseverance team is putting the final touches on the complex choreography required to land in Jezero Crater,” said Jennifer Trosper, deputy project manager for the mission at JPL. “No Mars landing is guaranteed, but we have been preparing a decade to put this rover’s wheels down on the surface of Mars and get to work.”
If you want to watch the Mars landing live, starting at 3:48 PM EST, you can do so on the NASA YouTube channel linked below. We’ll continue discussing some of what Perseverance faces after the jump:
At 3:38 PM EST, the cruise stage and entry capsule will separate. Atmospheric entry begins at 3:48 PM. The fact that Mars has an atmosphere in the first place allows NASA to use some of the same tactics it uses to return spacecraft to Earth, but Mars’ atmospheric pressure at sea level is less than one percent of Earth’s. Small, light objects can parachute down from orbit the same way they would here, but larger, heavier craft require special tools.
Note: NASA actually has a term for “Purposefully hurling your spacecraft at the ground in an attempt to stop it.” While most of us would refer to this as “crashing,” it turns out that’s only the appropriate term when you hit the planet accidentally. When you throw yourself directly at the planet intentionally, it’s called “lithobraking.” Perseverance is much too heavy for lithobraking, so NASA will deploy a tool it last used for Curiosity: A rocket-powered hover crane.
NASA technically calls this its “Sky Crane,” but in a survey of myself, “Rocket-powered hover crane” polled higher. It’s also a more accurate description of what the Sky Crane actually does.
This image from Curiosity’s landing shows exactly the same procedure NASA plans for Perseverance. After it enters the upper atmosphere, Perseverance will brake itself via parachute and retro-rockets. Retro-rockets, however, kick up a tremendous amount of dust if used too close to the surface, potentially damaging the rover. The surface descent stage will lower Perseverance to the surface of the Red Planet from an altitude of ~25 feet. If all goes well, the rover will signal its own survival at approximately 3:55 PM EST.
Perseverance carries its own unique payload of scientific instruments compared with Curiosity and will conduct its own investigations of Jezero Crater as it uncovers past and present conditions on Mars. It also carries the helicopter Ingenuity, intended to be the first powered aircraft to fly on another planet.
Feature Image: NASA/JPL-Caltech
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