[HN Gopher] Perseverance rover's descent and touchdown on Mars [...
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Perseverance rover's descent and touchdown on Mars [video]
Author : jvanderbot
Score : 345 points
Date : 2021-02-22 19:34 UTC (3 hours ago)
(HTM) web link (www.youtube.com)
(TXT) w3m dump (www.youtube.com)
| interestica wrote:
| Some things:
|
| Open source bits and shout out: The rover has an intel-based PC
| running linux. The video is compressed using FFMPEG.
| (https://youtu.be/gYQwuYZbA6o?t=4027)
|
| 30GB of data. 23 000 images (https://youtu.be/gYQwuYZbA6o?t=562)
|
| 1 of 3 cameras failed when the mortar/parachute fired.
| (https://youtu.be/gYQwuYZbA6o?t=615) (some other items were
| damaged/disrupted during the firing as well - not desired, but
| expected)
|
| When packed, the parachute has the same density "as oak". it
| trails at about 150 feet.
|
| The parachute pattern detail is intentional - sections to assist
| tracking diffent portions, etc.
|
| There appears to be some sort of secret message encoded in the
| parachute: "sometimes we leave messages in our work for others to
| find...give it a shot and show your work"
| (https://youtu.be/gYQwuYZbA6o?t=1174)
|
| They did not get audio from the port-side mic on descent due to a
| analog-to-digital comms malfunction (specifically stated that it
| was not a hardware issue). (https://youtu.be/gYQwuYZbA6o?t=3518)
|
| The heatshield is aeodynamically stable and does not tumble/spin
| on ejection.
|
| No plumes from the 'sky crane' because the exhaust products of
| hydrazine are hydrogen and nitrogen. The only hint that the
| rockets are firing are the slight colour change due to the heat
| (pink). The photos/videos are the first views of the sky crane in
| action because it's not something that can be tested on earth.
|
| The High-gain antenna has only _now_ been deployed. That 's the
| one that allows the high speed 2mbps rover-to-orbiter link.
| (https://youtu.be/gYQwuYZbA6o?t=2039)
| (https://mars.nasa.gov/mars2020/spacecraft/rover/communicatio...)
|
| There's a shot of all the pieces and their landing/crash sites as
| taken from orbit. Heat shield, perseverance, back shell, descent
| stage/sky crane, parachute. (https://youtu.be/gYQwuYZbA6o?t=2251)
|
| There are two mics. One captured some audio on the surface. A
| gust of wind. (more interesting to me was the hum of the rover).
| It would be cool if the audio from the mics could be used to pair
| with the panoramic view to create spatial audio.
| (https://youtu.be/gYQwuYZbA6o?t=2333) Because the EDL mic is
| 'off-the-shelf' it is expected to fail quickly in the Mars
| environment. They have no immediate plans to use it for any kind
| of diagnostics during its lifetime.
| (https://youtu.be/gYQwuYZbA6o?t=4215) ( _It would be cool if the
| audio from the mics could be used to pair with the panoramic view
| to create spatial audio._ )
|
| The cameras used are off-the-shelf commercial hardware with some
| modifications. Purchased from Point Grey Research (which was
| acquired by FLIR Systems). (https://investors.flir.com/news-
| releases/news-release-detail...) Most interesting mod: they had
| to replace some materials that could off-gas in space/vacuum and
| potentially deposit on the detectors.
|
| The data rate changes depending on the different orbiter being
| used. "return 500-900 megabits per pass" and 2-3 overlfights per
| night. (https://youtu.be/gYQwuYZbA6o?t=3928) And some of the
| biggest data relays were via European/ESA Trace Gas orbiter.
| (https://exploration.esa.int/web/mars/-/46475-trace-gas-orbit...)
| (https://youtu.be/gYQwuYZbA6o?t=4097)
|
| With all that, these press conferences are so weird. They still
| use a lot of acronyms. The setup is strange when there's no
| actual audience in front of them. They don't actually answer the
| questions from the press sometimes. They attempt to describe
| aspects of videos/images ("on the right you can see an antenna")
| instead of using technology to actually _show_. It 's not quite
| clear who the audience is here: they're combining questions from
| kids and the press. It would be helpful if they annotated images.
| It would also be helpful to place the questions on screen (who
| has asked them). But, still so damn exciting.
| jvanderbot wrote:
| Personally, I didn't work on this, but I'm completely amazed. To
| think Curiosity did this 8 years ago as well is kind of
| staggering to me.
| tibbydudeza wrote:
| Just amazing.
| joeyh wrote:
| This was recorded by a computer running Linux, using ffmpeg.
| Embedded Intel system with fairly stock cameras.
|
| "the first open source linux box running on the surface of Mars"
|
| "thank you to the open source community for allowing us to use
| your amazing software"
|
| Per their press conference today, in the Q&A section.
| https://youtu.be/gYQwuYZbA6o?t=4025
| aphextron wrote:
| As incredible as this footage is, it's even more mindblowing to
| realize we've been doing this for _50 years_ now. We know how to
| land on mars. Time to do it with people.
| NortySpock wrote:
| I agree we should send people as soon as reasonable, but this
| system is deploying about 1 ton of payload, which isn't going
| to go very far in terms of life-support equipment (dried
| rations, maybe... air scrubbers? No.)
| ArkanExplorer wrote:
| The issue with landing people on Mars is that you have to fly
| them back to Earth.
|
| We have to be prepared to 'die on Mars'.
| NikolaeVarius wrote:
| This method has been used twice, it is nowhere near human
| rated, hence why its called the 7 minutes of terror. For all
| the engineering, it has to be perfect or splat
| holoduke wrote:
| Whats the point of doing it with humans. Robots are getting
| better every year. Humans not really. Robots will most likely
| first build an settlement on mars before humans will arrive.
| rtkwe wrote:
| We know how to land relatively small things on Mars landing
| humans will be a much larger craft and because of that a harder
| task.
| yread wrote:
| But you don't have to worry that much about kicking up a lot
| of dust (the self-loading meatbags on board can clean your
| solar panels) so you can just point your thrusters at the
| ground and play with the throttle a little
| rtkwe wrote:
| It's not just the landing, that's relatively simple and can
| be mostly done with bigger thrusters on the craft but you
| have to slow down a lot before you can safely. Right now
| that's done through a heat shield then a parachute and
| finally the actual propulsive landing of the SkyCrane.
| We've done some testing of inflatable shields for the first
| step but nothing practiced actually in the Martian
| atmosphere yet and parachutes aren't great for heavier
| things.
|
| You want to use the other two to slow down as much as
| possible so you're not hauling extra fuel all the way to
| Mars. Ideally you'd be using ISRU units to generate your
| return fuel too.
| albertzeyer wrote:
| https://en.wikipedia.org/wiki/Life_on_Mars
|
| > To date, no proof has been found of past or present life on
| Mars.
|
| I wonder how long it takes until we get the first confirmation of
| some sort of life on Mars (e.g. something like bacteria or so).
|
| Is this realistic already in the coming days?
| carabiner wrote:
| 1996: https://www.youtube.com/watch?v=pHhZQWAtWyQ
| albertzeyer wrote:
| So far life on Mars was not really confirmed, right? I
| thought this is the main goal of this mission.
|
| https://en.wikipedia.org/wiki/Perseverance_(rover)
|
| > The rover's goals include looking for past Martian
| environments capable of supporting life, seeking out possible
| microbial life in those environments, ...
|
| Also see: https://en.wikipedia.org/wiki/Life_on_Mars
|
| > To date, no proof has been found of past or present life on
| Mars.
| carabiner wrote:
| Nope. Still remarkable that a president would comment
| officially on a NASA finding like that. It's the closest
| thing yet.
| DavidPeiffer wrote:
| I'd love to see this video with some real-time overlays. Landing
| spot identification with a 90% confidence zone, hazard
| identification, altitude, etc. I'm also curious how much hazard
| identification was done in real time versus a pre-programmed map.
| interestica wrote:
| 360 view on surface. Viewable in VR
|
| https://youtu.be/wE-aQO9XD1g
| meepmorp wrote:
| I was really surprised at how fast the heat shield dropped away,
| and slightly disappointed that we didn't get to see it hit the
| ground.
| jvanderbot wrote:
| HiRise captured the whole shebang: An image with the lander,
| heat shield, descent stage, and parachute. The descender is
| always a big black smear after these things, which is quite
| sad.
|
| I'm looking for the link, but the NASA TV feed had it.
| teraflop wrote:
| Here you go: https://www.nasa.gov/image-
| feature/jpl/perseverance-and-mars...
| meepmorp wrote:
| Well, there goes the rest of my afternoon.
|
| Edit: no video I can find; I'd just find satisfying to watch
| it hit the ground, in real time.
| HenryBemis wrote:
| I was hoping for the same, but at 9.5km away, and with a
| decelerating speed of 150m/s we wouldn't see but only a pixel.
|
| I wonder if they have the time/it's in their plan to send the
| bot over to record where it landed, the state that it's in,
| etc. If they want to simulate assess the damage, it would be
| cheaper to make heat shield 50 of them on Earth and drop them
| from 10-15km. I assume that every minute is gold and they
| already got a X-days meter-by-meter plan on what to do with
| little room for free exploration.
| Nekhrimah wrote:
| > I wonder if they have the time/it's in their plan to send
| [Perseverance] over to record where [the heat shield] landed
|
| I was thinking the same, but more for the fact that surely
| the impact has made a hole of some description that could be
| interesting to look into. Take advantage of the already
| expended energy to penetrate the surface layers.
| Daniel_sk wrote:
| But it would be contaminated, toxic and dangerous for the
| rover (it would contaminate or damage the instruments). Not
| worth it.
| ZuLuuuuuu wrote:
| This is incredibly impressive. I can't imagine the complexity and
| the effort it took to make the sky crane maneuver at the end
| possible.
| somedude895 wrote:
| This is incredible quality. What's the file size of the video and
| what path did the data take?
| rtkwe wrote:
| It got sent back via orbiters ranging from the ESA's Trace Gas
| orbiter, the Mars Reconnaissance Orbiter or Mars Odyssey.
| Through those they can get up to 2 megabits per second [0] back
| to earth but that depends a lot on the orbiter it's talking to
| at a given time. The TGO is doing a lot and is one of the early
| high speed relays for the data from Perseverance. [1] There's
| also direct links to and from Earth but they're significantly
| slower.
|
| [0]
| https://mars.nasa.gov/mars2020/spacecraft/rover/communicatio...
|
| [1] https://scitechdaily.com/nasas-mars-2020-perseverance-
| rover-...
| donarb wrote:
| The more impressive part is that the sky crane shot pictures,
| video and data and had to download everything to the rover
| before it was cut loose. As soon as the rover wheels touched
| ground, the tether was cut and the lander flew away.
| rtkwe wrote:
| That's relatively simple just wire them directly into the
| rover to start with so the data is always in the right
| place.
| cguess wrote:
| I believe the data is uplinked through orbiters than relayed
| back from there.
| jvanderbot wrote:
| The briefing said they had downloaded ~20 GB of data over the
| last few days. I'm sure much of that was _not_ EDL data.
| interestica wrote:
| _30_ GB of data and 23000 images. Crazy.
| https://youtu.be/gYQwuYZbA6o?t=562
| 1-6 wrote:
| "ready to begin seeking the signs of past life."
|
| This is a brilliant engineering feat but I don't agree with the
| premise of that statement.
|
| This is NASA's own mission statement: "The goal of the Mars
| Exploration Program is to explore Mars and to provide a
| continuous flow of scientific information and discovery through a
| carefully selected series of robotic orbiters, landers and mobile
| laboratories interconnected by a high-bandwidth Mars/Earth
| communications network."
| wobblykiwi wrote:
| What you're saying isn't quite true. Perseverance's mission IS
| to find signs of past life.
|
| See: https://mars.nasa.gov/mars2020/mission/science/goals/
| 93po wrote:
| The latter sounds like politically correct wordiness to not
| piss off the large amount of the planet that believes in
| intelligent design
| O5vYtytb wrote:
| I don't know why I'm surprised at the amount of footage and the
| quality, but I am. This is really setting a new bar for missions
| like this, similar to what SpaceX has done in recent years. Stuff
| like this has got to be huge for getting interest and excitement
| from the general public and especially kids.
| krm01 wrote:
| It would be great to see some startups work on interplanetary
| video streaming tech. If you're building an other video
| streaming service, stop what your doing, and give this a try. I
| know I know. Very, very hard to solve and all, and this is
| totally a fanboy speaking, but it would have been awesome if we
| could have seen this footage in (as close as possible to) real-
| time when the landing happened.
| djxfade wrote:
| So, the minimum delay between Mars and Earth is around 11
| minutes, usually higher. And the bandwidth is something like
| 60 MiB/Sol. This is just totally unrealistic with any known
| tech for the foreseeable future
| apendleton wrote:
| Current delay is ~11 minutes, but minimum is much lower (~4
| minutes, per https://blogs.esa.int/mex/2012/08/05/time-
| delay-between-mars... ). We were last at that closest point
| in October, and the various voyages (this one, UAE's Hope,
| China's Tianwen-1) were timed so the closest pint was
| during the transit; we're a bit past it now.
| giantrobot wrote:
| Nothing about "interplanetary streaming" needs to be
| invented. The limiting factor is the size and power of the
| transmitter on Mars (or wherever). The MRO orbiter for
| instance is the highest bandwidth probe we've sent to Mars
| and it maxes out at about 4Mbps when Mars is closest to
| Earth. When Mars is farther it can only do about 500Kbps.
| That relatively prodigious rate requires the use of 34m
| receiving antennas on Earth.
|
| So if you wanted to stream video from a GoPro on a Mars
| orbiter you could do so with current technology, you'd just
| need to build some big-ass antennas on Earth and then build
| and launch the Mars orbiters. Besides being technically
| difficult (because rocket science) it would be really
| expensive.
| subsubzero wrote:
| agree! I remember seeing still pictures from mars from the
| viking missions taken in the 70's and although they are pretty
| good this latest video quality and clarity means NASA/JPL has
| come a long way. Just seeing that alien surface where no person
| has(yet) walked is absolutely amazing.
| spookthesunset wrote:
| I still can't get over the fact this mission has legit good
| cameras on it.
| tppiotrowski wrote:
| Can someone comment on why this is the first time I'm seeing
| videos from Mars versus previous missions.
|
| Did the memory write speeds increase, more sensitive CCD sensors,
| easier to send data back to Earth?
|
| I'm sure there must be some technological reason this wasn't done
| before because it's simply stunning...
| pkaye wrote:
| The commercial cameras have gotten so good over the years so
| they could put cameras everywhere. They added some local
| storage to retain images for post processing. They post process
| the videos to a much smaller file before transmitting. So of-
| the-shelf technology keeps getting better.
| DataGata wrote:
| One thing to consider is that NASA missions are basically
| always using older technology, because by the time the mission
| gets approved, designed, and built consumer/business tech has
| already moved past. Space worthiness ads more 'age' to the
| technology as well.
| tppiotrowski wrote:
| I remember when New Horizons flew by Pluto in 2015 taking
| pictures with a 1 MP camera. At that time I had an 8 MP
| camera on my phone, but remembered that in 2006 when New
| Horizons launched, the iPhone didn't even exist.
| ctdonath wrote:
| The current scale of video availability is very recent. Dirt
| cheap tiny HD cameras and storage & fast reliable networking to
| match, are only a few years old. Put that in context of a
| complex system expected to work perfectly under extreme
| conditions millions of miles distant, with early designs
| starting years ago, and that's why you're only seeing such now.
| 93po wrote:
| There's a ton of media from previous mars missions. Can't
| comment on why you didn't see them
| tppiotrowski wrote:
| I'm curious about videos specifically. I've seen a lot of
| high-res images and animated GIF style videos but nothing
| like this.
| apendleton wrote:
| Not an expert, but my sense is that it's at least in part due
| to widespread cheap/commodity consumer cameras becoming a thing
| between the planning of Curiosity and the planning of
| Perseverance. In earlier missions, cameras were usually big and
| bulky and designed specifically for their respective research
| functions, and if you're designing something from scratch, you
| design it to maximize research utility first, and sending home
| cool videos is probably a secondary consideration. So I'm not
| sure many of these could do video (because it's probably not
| that useful for studying rocks that don't move), and a lot of
| them didn't even capture a spectrum range exactly matching the
| visible range (I think some of them included parts of the near-
| IR range, etc.), so a lot of the images from earlier missions
| that were released to the public had color that was
| faked/recreated in post-processing.
|
| I think the new rovers still have these specialty cameras, but
| now that there are decently good mass-market cameras from the
| cellphone/consumer-electronics industry that cost $5 apiece and
| weigh a couple of grams, it seems like there's no reason not to
| throw a few of those onboard as well.
|
| I would speculate, also, that video compression might be part
| of the story. Processors on these vehicles tend to be
| specialized radiation-hardened chips that are modified versions
| of several-generations-old general-purpose processors. I think
| Curiosity's was a rad-hardened 200MHz PowerPC chip, for
| example. I would bet that those chips just weren't up to the
| task of compressing high-quality video enough to make it
| practical to send, given the bandwidth constraints of
| transmitting from Mars to Earth.
| Daniel_sk wrote:
| It didn't have priority until now. Everything costs time and
| money and adds more complexity, more parts that can cause a
| failure. While videos are nice, they don't have such scientific
| value as another scientific instrument that could have been on
| board instead.
| spookthesunset wrote:
| > While videos are nice, they don't have such scientific
| value as another scientific instrument that could have been
| on board instead.
|
| While they don't have much scientific value, they have an
| extreme amount of value in a related field: marketing.
|
| I mean, if you want more money for your hot new space rover
| mission nothing sells it better than high resolution quality
| videos of it landing on the surface of another planet.
| spookthesunset wrote:
| As it got closer to the ground, it seemed really hard to get a
| sense of scale with that downward camera. It felt like the ground
| just kind of "appeared" right before the sky crane did its thing.
| How big are the rocks under it? It felt like they were either big
| (1+ meter) or just little pebbles. I really couldn't tell.
|
| Either way, this is seriously the coolest video I think I've ever
| seen. I cannot wait for more.
| ckosidows wrote:
| Agreed with both. I hope someone can eventually put an
| estimated 3D model of something familiar, like a person or a
| school bus or something, for scale in the image video.
|
| And this is one of the coolest videos I've ever seen. I had a
| huge smile watching all of it. I can't even fathom how elated
| the whole JPL team must have been as these videos came in.
| Trasmatta wrote:
| At about 2:57 the operator says the rover is about 20 meters
| off the surface, if that helps at all. I agree it got really
| hard to get a sense of the scale once the thrusters started
| blowing up dust.
| spookthesunset wrote:
| I rewatched listening to all that and it helped but only in
| an abstract way. It's like there needs to be a penny in the
| shot or something to get a sense of scale.
| ro2nie wrote:
| No, not a penny. It needs a banana for scale
| aent wrote:
| Here's a recording of the martian wind from one of the rover
| microphones https://soundcloud.com/nasa/first-sounds-from-mars-
| filters-o...
| aosaigh wrote:
| In case the other thread doesn't make the front page, they also
| added a microphone to this lander and managed to capture the
| sound of Mar's wind, which to me is almost more amazing:
|
| https://soundcloud.com/nasa/first-sounds-from-mars-filters-o...
| bane wrote:
| I may be wrong, but I believe this goes back to a suggestion
| made decades ago by Carl Sagan. Despite being in the mission
| profile for a number of missions, it never made it (and turned
| on) until now.
|
| https://www.planetary.org/sci-tech/mars-microphones
| martian wrote:
| Obligatory audio from Venus, Venera 14 lander:
| https://www.youtube.com/watch?v=8jZDW53U8qQ&t=0s
|
| With annotations:
| https://www.reddit.com/r/venus/comments/7vpr1w/sound_recordi...
| geocrasher wrote:
| And it's _not_ a Rick Roll. Well done.
| wycy wrote:
| Pretty cool, although it's so hard to really get a sense of
| sound of wind with a microphone. I guess the takeaway is that
| Mars is super quiet.
| jandrese wrote:
| 1% atmospheric pressure would do that. Sound won't travel
| very well through the Martian atmosphere.
| wycy wrote:
| Wow, very interesting. I had a pre-conceived notion that
| Martian atmospheric pressure was something like 20% of
| ours, but you're right, it's quite a bit lower than even
| that.
| jzer0cool wrote:
| Mars is dominated by linux machines, ai and machine learning. As
| I stared at the landing I thought what if it drops into the
| crater and cannot climb out? At the same time I was really hoping
| I would see also little antennas poking out from the ground
| underneath or little martians running around hiding from the new
| strange visitor. What's the first mission?
| [deleted]
| netcraft wrote:
| So glad they've realized the value in allowing everyone to
| experience how hard these things are. So impressive, I can't wait
| to watch this video over and over.
|
| The inflation of the parachute is spectacular, and knowing how
| hard it is, and how hard it is to test on earth - its just
| incredible.
|
| And the skycrane was flawless - just so impressive how well it
| works. Too bad it flies off to crash and can't land gently
| somewhere to maybe be able to use it for its own purpose.
| baggy_trough wrote:
| If there was mass available to add something to the sky crane,
| you'd be better off putting that thing on the rover, since the
| rover has the plutonium power pack.
|
| I do feel a bit sorry for the crane as well though :)
| spookthesunset wrote:
| This is what I was thinking. That sky crane has to be as
| barebones as can possibly be made. Every single bit of mass
| on it is something that could be better used elseware.
|
| Tradeoff of course is if you skimp on the mass too much
| you'll get an unreliable sky crane and the whole thing is a
| dud.
| holoduke wrote:
| There have been made tremendous steps in simulation software. The
| fact that the crane mechanism has never been tested on earth
| besides simulations is incredible. Always wondered what software
| they use. Do they have a generic platform to run simulations on?
| Or is every mission written from scratch?
| 2sk21 wrote:
| Not quite, the sky crane method was also used for Curiosity
| rover back in 2012
| udev wrote:
| There is this emotion, not sure it has a name, which I am sure
| many engineers know -- when you prepare your system for a long
| time and then send it into the real world and watch it work...
|
| You can feel it in this video, e.g when you see the crane fly
| away after accomplishing the mission.
|
| If we don't have a name for this emotion yet, I hope the japanese
| or the germans invent one. :)
| raldi wrote:
| _Now these points of data make a beautiful line_
|
| _And we're out of beta, we're releasing on time_
| yazaddaruvala wrote:
| I think its similar enough to "closure" to re-use that word.
| ctdonath wrote:
| "It worked! On to the next task..."
| mhh__ wrote:
| Pride
| XVII wrote:
| I'll just invent one:
| 'Funktionsfahigkeitsdemonstrationseuphorie'
| LargoLasskhyfv wrote:
| Schopferstolz. Schaffensfreude.
| rx_tx wrote:
| One of the engineers said that the parachute's patterns was both
| for visually determining the orientation (with computer vision),
| but also hinted there was some secret message in it. (at 19:34 in
| the livestream)
| nsriv wrote:
| The rover wheels on Curiosity had gaps so that the tire tracks
| left a pattern in morse code that spelled out JPL, so maybe
| something similar? They eliminated that on Perseverance with
| the wheel redesign.
| rx_tx wrote:
| Yeah that's what I think, but it could also encode something
| longer. I am not sure on the parachute what is a science
| feature and what is an easter egg.
| geocrasher wrote:
| This may sound silly, but: The closest I've coming to building a
| "robot" was a simple little arduino kit. The kit was terrible,
| the parts defective, and you can imagine I was pretty sick of
| troubleshooting it after a time. These are things happening on my
| workbench with a small amount of automation code. I'd have been
| thrilled if it had just worked as designed.
|
| Now, take three robots. One is wheeled, one flies by rotors, and
| another is rocket powered. Put them on a rocket, fly to another
| planet, and land them autonomously without wrecking anything. As
| a hobbyist I'd be beyond myself to just do ONE of those. On
| Earth. Let alone millions of miles away on a _distant planet_.
|
| And to get _video_ of it just days later, bounced across multiple
| orbiters? Mind blowing.
| bryan0 wrote:
| One of the engineers does a great shot-by-shot commentary of this
| video about 15 minutes into their live stream:
| https://www.youtube.com/watch?v=gYQwuYZbA6o
| jonplackett wrote:
| I'm now waiting for the complainers to be all like "But I wanted
| to see it in VR, this sucks"
| davidg109 wrote:
| After such a shitty 2020, this is just what we needed.
| Incredible.
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(page generated 2021-02-22 23:01 UTC)