To cleanse the palate, supreme space-nerd content here in the form of newly released footage from NASA. If you’re wondering why this wasn’t published days ago, after the rover touched down, it’s because uploading video from 130 million miles away takes a bit longer than it does on terra firma. According to Space.com, Perseverance can send 2MB of data per second to the Mars Reconnaissance Orbiter, which then relays that data to NASA’s Deep Space Network of antennas. A full video lasting several minutes, from multiple angles, obviously requires patience.
But it was worth the wait, as you’ll see.
The easiest way to explain what’s going on in the clip is to refer you to this graphic, which illustrates the various stages of landing. First the clamshell-like pod enters the Martian atmosphere, absorbing tremendous heat in the process. A giant parachute deploys to slow its ascent. As it slows down, the now-superfluous heat shield is jettisoned (at 0:30). That leaves the “backshell” and its attached contents — a “sky crane” and the rover itself, attached to the crane by three cables. What makes the landing so treacherous is that Mars is too far away for the craft to be guided safely moment by moment via transmissions on Earth. It has to navigate autonomously. “Seven minutes of terror,” they call it:
“Perseverance will be the first mission to use Terrain-Relative Navigation,” Mohan says in the video. “While it’s descending on the parachute, it will actually be taking images of the surface of Mars and determining where to go based on what it sees. This is finally like landing with your eyes open — having this new technology really allows Perseverance to land in much more challenging terrain than Curiosity, or any previous Mars mission, could.”
Perseverance’s EDL sequence is very similar to that of NASA’s Curiosity rover, which landed in 2012. However, Perseverance is slightly bigger and equipped with more advanced scientific instruments, including new technology that will help guide the spacecraft through its difficult landing.
As the craft begins to steer towards the surface, the “backshell” falls away, leaving only the sky crane and the rover to keep falling. The sky crane cushions the rover’s landing by firing retro-rockets to keep it aloft while lowering the rover softly to the surface via three cables, which are clearly visible in the clip. (The “wind” seen at 2:43 of the clip is from the force of the retro-rockets firing against the surface, I assume.) Once the rover’s down, the cables are cut and the sky crane flies away. You can see, then, how they managed three different camera angles for this descent. Because there were so many components, they were able to install five cameras to track it from different points: “Two cameras on the back shell, which encapsulated the rover on its journey, took pictures of the parachute inflating. A camera on the descent stage provided a downward view – including the top of the rover – while two on the rover chassis offered both upward and downward perspectives.”
Piece of cake.
They weren’t landing on any ol’ patch of Martian soil either, by the way. The navigation system wasn’t designed merely to help the craft land safely, it was designed to land it in a particular spot — the Jezero Crater, “an ancient lake bed and one of the most promising places to look for evidence of ancient microbial life.” That’s a comparatively small bullseye, and the lip of the crater potentially makes it more dangerous for a landing than a plain would be, but they nailed it.
By the way, if you want to hear what Mars sounds like, go here and turn your speakers way, way up. There’s a faint breeze detected. Pretty quiet place, Mars.