The rover named Perseverance landed on the surface of Mars. It is big, weighing about a ton, and since the atmosphere of Mars is so thin, parachutes are not sufficient to slow it enough to use airbags to cushion the final landing so they had to find another way.
Perseverance approached Mars at around 12,400 miles per hour, although when it hit the top of the atmosphere, a heatshield slowed it down to about a tenth of this speed. Then a supersonic parachute popped out of the rover to reduce its speed to a few hundred miles per hour.
At that point, descending under the parachute, Perseverance was still travelling far too fast to land safely. So it cut itself loose from the parachute and used rocket thrusters to slow down further. The thrusters allowed it to hover roughly 20 metres above the surface, before the rover was lowered by cables to the surface using a rocket platform called a sky crane.
Here is a video simulation of the landing.
You have to hand it to the engineers and scientists behind this project for a really impressive achievement.
You can see some of the first still images sent back here. There should be video soon too.
Maybe human biological life is an important evolutionary step toward robotic life. Someday robotic philosophers will poopoo the idea that fragile stupid slow biological life-forms could be how they ascended from the gravity well.
From the edge of my seat as I watched them talk it in, the main thing that struck me was just how bloody FAST it went in, right up to the last moment. Oh, we’re at just under 70km altitude. Less than 40. Less than 10. 2. 200m. JESUS! It was PLUMMETING. The fact that approach ended in a soft landed is bordering on miraculous. So impressed.
On Earth or on Mars? 🙂
(I know you’re writing for a general audience, but still… weight vs. mass)
Wait . . . is a “sky crane” similar to the “sky hook” that novice construction workers are sent to retrieve on their first days on the job?
I’ve heard it said that Mars has just enough atmosphere to destroy your lander without being able to slow it down. The worst of both worlds, as they say. While they arrived last week, the Chinese will put their lander/rover down after they’ve circularized their orbit (a month or so). But they’re using the “old fashioned” airbag technique NASA used with Pathfinder. It’ll give them a 3 in 1 space probe (Orbiter, lander, rover). It’s quite telling that when everybody else comes in and subtly circularizes their orbit via lithobraking, the US just slams in at planetary transfer speed, waving a cowboy hat and screaming “Yee Haww!! ala Slim Pickens in Dr. Strangelove.
Also, NASA has published a picture from the sky crane on it’s website. It’s currently what comes up first on the home page. https://mars.nasa.gov/mars2020/
Guys this is the exact same method used by the Curiosity rover. I’m not saying it’s not cool or anything, but this technology is sooooooooo 2012. 😉
drken:
You mean aerobraking.
Silentbob:
The design was a little more sophisticated than Curiosity’s. The newer EDL system used cameras and other sensors to search for a nice landing site on the way down, instead of a more predetermined landing sequence. As I understand it, the result is that it could go to some rougher terrain (and still find a safe place) inside of a smaller target ellipse.
All the software must be pretty impressive on its own. Not something that’s been described in much detail, unfortunately, but I sort of get it: most people want to hear about all the action with heat shields and parachutes and rockets and whatnot.
Sorry, I just realized that’s what the BBC video above is about. The preview image looked like another video that I saw yesterday, but then I clicked….
Regarding the shape of the lander, the CBC Radio science reporter pointed out the irony that Earth was sending a flying saucer to Mars.
@8, Yeah, I’d assumed it was just the great† JPL / Nasa video intact, not realising the BBC(?) had cut down that video to final sequence, interspersed with other video, and added an audio commentary about TRN.
† Minor quibble — audio in space. Whilst the audio added to the video in an artistic sense, it also subtracted from its factual accuracy. Perhaps more annoying, the description of the video does not point out the impossibility.
They were able to land in this relatively dangerous location because of Terrain Relative Navigation.