[HN Gopher] Perseverance Rover lands on Mars [video] ___________________________________________________________________ Perseverance Rover lands on Mars [video] Author : malloreon Score : 435 points Date : 2021-02-18 19:16 UTC (3 hours ago) (HTM) web link (www.youtube.com) (TXT) w3m dump (www.youtube.com) | adolph wrote: | Clicking on the solar system icon at the top of this page | provides a JavaScript version of NASA's Eyes solar system mapping | application. You can look up the Perseverance mission as "Mars | 2020" right now. | | https://solarsystem.nasa.gov/interactives/ | MisterBiggs wrote: | NASA works. | [deleted] | davidw wrote: | I love space science and engineering! It's such a beacon of hope | and a demonstration of what we can do when we work hard and | innovate. And it's pretty interesting in its own right. | jaegerpicker wrote: | Yes, especially during the Covid pandemic and the political | unrest in the US. Space exploration has helped keep me sane and | to have some hope for mankind. | Shivetya wrote: | Also on https://www.twitch.tv/nasa | | They were showing off a model of the rover, I did not realize | just how large this one is! | [deleted] | crubier wrote: | Space exploration is unlike anything else. Perfect combination of | exploring unknowns + badass robots + science. | tectonic wrote: | You can also watch an EDL visualization in your browser: | https://eyes.nasa.gov/apps/mars2020/#/home | | And read about how it will use Terrain Relative Navigation to | find a safe landing spot: https://www.jpl.nasa.gov/news/a-neil- | armstrong-for-mars-land... | | Perseverance is phenomenally complex, its Sample Caching System | alone contains 3,000+ parts and two robotic arms. So exited for | all the sciencing this nuclear-powered, sample-drilling, laser- | zapping behemoth can do when it joins its friends on the only | planet (known) to be inhabited solely by robots. | | Edit: Percy is about to release its two 77 kg Cruise Mass Balance | Devices (is this what NASA calls 'weights'?) to setup the right | lift-to-drag ratio for entry. Mars InSight will be listening for | the 14,000 km/hr impacts of these weights, providing useful | calibration data. We wrote about this in this week's issue of our | space-related newsletter, Orbital Index - | https://orbitalindex.com/archive/2021-02-17-Issue-104/ | tectonic wrote: | Also, InSight's SEIS seismometer is a true marvel: "We have | been able to detect, at about 10 hertz, displacement of the | ground of the order of less than 5 picometers...which is a | fraction of the size of an atom." -- | https://eos.org/features/a-modern-manual-for-marsquake-monit... | koheripbal wrote: | Any idea when they will start experimentation? I want to find | microbial life! | WJW wrote: | > is this what NASA calls 'weights'? | | Well no, the Cruise Mass Balance Devices are intended to | Balance the Mass of the spaceship during Cruise conditions. | That these Devices are single-part and constructed out of a | single chunk of metal each should not be construed as merely | being 'weights'. :) | nelsonmandela wrote: | Apparently the copter was made with off-the-shelf parts. | | I wonder if I can cop a replica somewhere, and how it would fly | considering it is built for martian air | kibwen wrote: | Here's a really excellent video that answers all your | questions: https://m.youtube.com/watch?v=GhsZUZmJvaM | | TL;DW: Martian atmosphere is so sparse that it's equivalent to | flying at 100,000 feet on Earth. (The altitude record on Earth | is 85,000 feet, set by the SR-71.) In order to fly at all the | blades have to spin at nearly the (Martian) speed of sound. The | drone wouldn't fly on Earth because the atmosphere is so dense | that the blades would never make it up to speed. | tectonic wrote: | A super exciting and well-executed landing with years of practice | ahead of time to make it look easy. Things I'm looking forward | to: - Sample collection and caching for pickup by a future sample | return mission | | - Flying an experimental helicopter on Mars | | - Gauging the habitability of its landing region (Jezero Crater, | a paleo-lakebed with preserved river delta and sediments) and | hunting for ancient microbial biosignatures (with lasers!) | | - A drill (that can cut intact rock cores, rather than | pulverizing them like Curiosity) | | - An ISRU experiment that makes oxygen from CO2 | | - Way more advanced autonomous navigation | pklausler wrote: | I very much enjoyed learning a new acronym: SUFR ("straighten up | & fly right", if I remember rightly). | me_me_me wrote: | Helicopters on Mars, what a time to be alive! | rpiguyshy wrote: | im really sad to say that NASAs website is an absolute dumpster | fire... does anyone know of a simple repository of all the images | and videos captured by each mission? i just want to flip through | the pictures perseverance has taken so far without sifting | through cancerous news sites. | | edit: the closest thing ive found is data.nasa.gov. how hard is | it to just generate a fucking simple html website with | chronologically ordered images? this is bullshit | | edit: ok, here is almost exactly what i wanted: | https://mars.nasa.gov/mars2020/multimedia/raw-images/ the | internet really sucks compared to what it might be... go to | nasa.gov and click percy mission from the drop down and it takes | you to a part of nasa.gov thats filled with eye-cancer tiles and | javascript with sensor imaging mixed in with PR images and | promotional material. but they tuck the (sort of) clean, | organized data into some other website basically? maybe its a | small gripe but this way of doing it is disorganized and | infuriating. | drewblaisdell wrote: | When can we expect any imagery from Perseverance? The Curiosity | photos were incredible. | ryankrage77 wrote: | Probably around 20-30 minutes after it's landed. Perseverance | needs to lock onto sattelites that are part of the Deep Space | Network for the bandwidth required to send media. It also takes | 22 minutes to send a command and get a response back. | ceejayoz wrote: | It was already communicating with DSN the whole way down, via | one of the orbiters, and "send a pic" was apparently a pre- | programmed command not requiring Earth initiation. | comfydragon wrote: | We actually got a picture like 3 minutes after landing. | (Okay, a picture from shortly after landing.) | someperson wrote: | Probably routed through the Mars Reconnaissance Orbiter, | Maven and possibly Europe's Mars Express satellites, rather | than a direct connection to the Deep Space Network | | https://en.wikipedia.org/wiki/Mars_Reconnaissance_Orbiter | | https://en.wikipedia.org/wiki/MAVEN | shadowgovt wrote: | If I understood the livestream correctly, it's because they | were able to (maintain|quickly establish) lock to the MRO | after touch-down and zip a couple of images up through the | "bent-pipe" UHF-to-high-power relay into the Deep Space | Network. | jasonjayr wrote: | First few low-res pictures posted here: | | https://twitter.com/NASAPersevere | | I'd bet they post the first high-res pictures once they arrive. | The link from Mars to earth is sending a lot of information | about what just happened, so understandably bandwidth is pretty | saturated | f154hfds wrote: | Pictures already coming in to JPL apparently. | | https://www.youtube.com/watch?v=kPrbJ63qUc4 | thisistheend123 wrote: | This is so awesome. Go Nasa! | | I am amazed at what humans have been able to achieve in short | time since the Industrial revolution. | | After all the negativity of last few months, this brings so much | hope. | | Waiting for the first human foot touch down on Mars in my | lifetime. | koheripbal wrote: | The pandemic has, in many ways, accelerated advancement and | technological development. | burrows wrote: | All hail the shining twin gods, Advancement and Progress. | sixothree wrote: | Shout out to the team member with the "This is fine" plush dog on | their desk. | arnaudsm wrote: | Picture : | https://twitter.com/PlanetDr/status/1362487492662996996 | thisistheend123 wrote: | How much more time for EDL? Can't find that information anywhere! | [deleted] | devb wrote: | I was wrong... estimated touchdown is 15:55 eastern time. | whitehouse3 wrote: | It's great to see NASA livestreaming in similar quality/fashion | to spacex. It reminds me of watching the NASA feeds on public | television in the 90's but much more nicely produced. | hikerclimber wrote: | hope it crashes. | hedgehog wrote: | I read that the design life of the helicopter is five flights. | Does anyone know what the limiting factors are? The brutal cold | and abrasive dust both seem like they could contribute but I am | curious what the real answer is. | bluescrn wrote: | Dust on the solar panel seems likely to be a problem after the | first landing, unless it's got a clever way to keep it clean. | | And its got to be tough conditions for the battery, low | temperatures and probably deep discharges to make the most of | it. | joeyh wrote: | It's powered by plutonium. | | Rovers with solar panels deal with the dust by waiting for a | storm to blow it away. | dmurray wrote: | The "design life" figure is something like the 5th percentile, | if previous rovers are anything to go by. As in, they can | estimate a 95% chance it makes it through 5 flights. | | I'd bet on it making 20+ at evens. | [deleted] | garden_hermit wrote: | Watching these is always a stressful experience, I can't imagine | what it would be like sitting in that room, praying that the | object you spend years of work on is able to land by itself 7 | light-minutes away. | | I'm looking forward to what Perseverance will teach us. | sneak wrote: | > _Watching these is always a stressful experience, I can 't | imagine what it would be like sitting in that room_ | | Sitting in any closed space like that one, with other people, | masks or no, is stressful right now. It's a shame that NASA can | communicate with a rover 125 million KM away but their staff | have to all be crammed into one small enclosed space. You'd | think we'd be able to communicate just as effectively over | several kilometers. | | I imagine that people will look back on videos from this time | period where ~3M people died (mostly unnecessarily) and wonder | what on Earth people were thinking, carrying on like that. | tester756 wrote: | what if those people were tested for covid and there was no | risk? | DonHopkins wrote: | That's how Trump got it, then spread it. | jussij wrote: | This morning on the radio and Australian scientist told the | listeners he had spent 10 years working on his small part of | the Perseverance mission. | | That would help to make the landing quite a nerve racking | event. | spullara wrote: | Right now it is 11 minutes away! | SubiculumCode wrote: | You know, in some ways its like any scientific endeavor. | Hypothesis, funding, data collection can take years of effort. | Then you look at your data and test hypotheses, and you have no | control of the outcome. It can be terrifying, to be honest, | which is why I support publishing of negative results. Of | course crashing on Mars would be a terrible null result ;) | ghoshbishakh wrote: | Thank you for posting this. Let's witness what science and | engineering is capable of achieve today. | | It is just amazing to think that a robot is roaming around in | Mars, and a second one might be joining today. | abalaji wrote: | I'm excited for the HD video of the landing that was promised. | Nekhrimah wrote: | And audio as well! | aembleton wrote: | How are they getting audio without an atmosphere? | gillytech wrote: | There is a thin atmosphere on Mars and sound does exist. | It's also how this lander was able to land. | Ne02ptzero wrote: | NASA actually made a pretty informative page about it[1], | with some simulation of sound on Mars, compared to Earth. | Hopefully we won't need the simulation much longer! | | [1] https://mars.nasa.gov/mars2020/participate/sounds/ | vagrantJin wrote: | Mars does have an atmos. | | Or are you reffering to something else? | tcpekin wrote: | Currently watching it using Streamlink [0] to watch in VLC. This | is so exciting! Wishing them, and the rover, all the best in the | landing! | | [0] https://streamlink.github.io/ | inspector-g wrote: | Watching the live feed was a blast. When they said they received | the exact landing coordinates I was extremely curious to see it | plotted vs their targeted landing zone, but unfortunately they | haven't shown it yet. However, I could audibly hear an engineer | in the background say "Oof, well, we'll take it!" | | Anyone seen anything about the precise location yet? | tectonic wrote: | https://twitter.com/jccwrt/status/1362514739671298051 | | > UNOFFICIAL but it looks like Percy landed right on the edge | of the Mafic Floor Unit, with older (probably sedimentary) | rocks that were buried by it only a short drive away. | raphaelj wrote: | NASA's ability of succeeding at landing things successfully on | the first try on foreign bodies since 1969 is mind-blowing. | | Meanwhile, SpaceX takes half a dozen tries before managing to do | the same on a fully known environment on Earth. | dawnerd wrote: | You had me until you started to bash SpaceX for no reason. NASA | has had plenty of failures and you're framing it as if they | haven't ever. | TulliusCicero wrote: | That snipe was really unnecessary. | | Not to mention weird, considering how successful SpaceX has | been at dominating the commercial launch sector. | gfodor wrote: | Consider for a second that blowing up no prototypes or blowing | up lots of prototypes are both well considered methodologies | and what you state is by design and expected. | emilecantin wrote: | Perseverance is one of the largest objects that NASA landed | (along with the Apollo lander), and it's about the size of an | SUV. | | SpaceX is trying to land things the size of buildings. | | Let's just say it's a very different problem. | Daho0n wrote: | . | m4rtink wrote: | Actually, all the Starship flights are fully automated, | possibly except a very nervous person somewhere with the | self-destruct button and binoculars. | | If you though there is someone in Boca Chica flying | Starship remotely with joystick and steady hand, I'm afraid | I need to disappoint you. | Daho0n wrote: | That wasn't the point but this is Reddit level snarky | commenting so I'll be on my way. | PeterisP wrote: | Neither Perseverence or SpaceX landings involve latency for | control commands, they are automated/preprogrammed in the | vehicle and do not rely on real-time commands from the | ground. | Daho0n wrote: | No one have said otherwise. The point still stands that | landing on earth is not in the same universe as landing | on Mars. Comparing is stupid. | jaegerpicker wrote: | SpaceX has a very different set of risk tolerances and | approaches. Nasa is a government funded entity and the | tolerance for failure (rightly or wrongly) is very low | according to every thing I've read. | | SpaceX being private has a much larger cushion for failure. | Elon will keep funding it far longer than congress would Nasa | is my guess. If SpaceX loses some rockets that's the cost of | business, of course once those missions are manned it's a huge | difference but until then I think it's not really comparable. | macintux wrote: | I'm sure this will be downvoted to oblivion shortly, but it's | mind-boggling that the company who's turned rocket landings so | routine that it's notable when they fail is being singled out | as a failure. | | (Update: sorry, by "this" I mean the parent comment.) | [deleted] | electriclove wrote: | We really should take the SpaceX approach. There is too much at | stake on a singular multi-billion dollar rover landing on Mars | every now and then. We need more funding so that we can send | these things to Mars much more frequently and get samples back | before my kids have their own kids. | FrojoS wrote: | Rediciolous comparison. | | The size of the objects that SpaceX is landing is much larger. | The approach that was used here for Perseverance (Skycrane) | would not work for larger ships, like those required for a | human mission. Just like the previous approaches, e.g. | Lithobraking with Spirit and Opportunity, would not have worked | for Perseverance. | | Larger objects are much more difficult to land. Simply put, | while mass will increase by the power of three, surface area, | which is used for aerobraking only scales by the power of two, | relative to size. | | In order to land something large enough to carry and support | humans (10-100t), you need hypersonic retropropulsion. Guess | who was the first to achieve this? SpaceX. And they remain the | only ones. When they light the three engines for the entry burn | the earth atmosphere is very similar to the relevant section of | the future Mars decent. By developing the first stage landing | of Flacon 9, they solved one of the biggest development | challenges for humans landing on Mars and it was not by | accident. NASA was very happy to get that data and helped them | collect it with their chase planes. | nitrogen wrote: | _NASA 's ability of succeeding at landing things successfully | on the first try on foreign bodies since 1969 is mind-blowing._ | | https://en.wikipedia.org/wiki/Mars_Climate_Orbiter | | > The spacecraft encountered Mars on a trajectory that brought | it too close to the planet, and it was either destroyed in the | atmosphere or escaped the planet's vicinity and entered an | orbit around the sun. An investigation attributed the failure | to a measurement mismatch between two software systems: metric | units by NASA and non-metric ("English") units by spacecraft | builder Lockheed Martin. | | https://en.wikipedia.org/wiki/Mars_Polar_Lander#Landing_atte... | | > Communication was expected to be reestablished with the | spacecraft at 20:39:00 UTC after having landed. However, no | communication was possible with the spacecraft, and the lander | was declared lost. | macintux wrote: | In fairness to the parent comment: those weren't the first | try. | user3939382 wrote: | Yeah, c'mon Elon. It's not rocket science! | joe_91 wrote: | NASA also requires 10-100x more money & time to do so. Both | just have very different ways of working. Both work and there | are pro's and con's to either way! | notum wrote: | I'll just leave Thunderf00t's latest video here: | https://www.youtube.com/watch?v=4TxkE_oYrjU | | Let's not diminish ether's breakthroughs, but financial isn't | one of SpaceX's. | raphaelj wrote: | How could you know? SpaceX never landed or sent a craft on a | foreign body. | joe_91 wrote: | Haha, good point - we'll have to come back in 4-5 years | time when SpaceX have touched down on the moon and mars and | check the cost. Considering their low cost & speed at | getting things into orbit these days and the plans they | have for starship I hope that the data will prove me right | in a few years | ALittleLight wrote: | SpaceX hasn't been around as long as NASA. Also, remind me, | did NASA develop reusable rockets? | Rebelgecko wrote: | NASA doesn't really build rockets in-house, all of their | reusable rockets were built by contractors under NASA's | supervision. Sometimes NASA collaborated with other | organizations (e.g. DARPA/military funding paid for a lot | of the DC-X reusable rocket) | m4rtink wrote: | Well, nssa worked on Delta Clipper and DC-X. Also Venture | Star. And the integrated powered demonstrator/FastTrack & | pointless injectors that formed the basis of the Merlin | engine IIRC. | thelean12 wrote: | > Also, remind me, did NASA develop reusable rockets? | | I can't tell if this is sarcasm or not but... yes, of | course NASA developed reusable rockets. The space shuttle | missions reused the shuttles and the boosters. | ALittleLight wrote: | The space shuttle was partially reusable. | marcinzm wrote: | The Space Shuttle was reusable (with massive refurbishing | after each flight) but given that'd it cost significantly | more than a non-reusable rocket per pound I think the | point stands. SpaceX managed to make a financially viable | reusable rocket. | thelean12 wrote: | > I think the point stands | | No it doesn't. The person was trying to say SpaceX > | NASA. Many people here are trying to shit on the other | side as if they have a real point. | | They're both doing cool and useful things and they're | both really really good at what they do. | ALittleLight wrote: | I'm not trying to say that SpaceX is better than NASA. I | am responding to the point that NASA has done things that | SpaceX hasn't (e.g. landing on other celestial bodies) by | pointing out that SpaceX has done things NASA hasn't | (e.g. SpaceX rockets land and can be reused). | | I don't think it makes sense to talk about which is | better unless there is some specific metric that can be | measured so a conclusion could be reached. I am | encouraged though that SpaceX has a trajectory that will | allow greater access to space. By bringing the cost of | space travel down, I expect we will get a lot more of it. | NASA (and other governmental space programs) started the | initiative, but I think SpaceX is continuing it | marvelously. | erulabs wrote: | They did, you're not wrong at all, but just to add a | little bit of clarity the space shuttle was never as | reusable as was hoped - it wound up costing a huge amount | of time and money to retrofit the shuttle again before | each launch. Reusable and Re-usability are different | things :P | | As far as I know no solid state boosters were ever re- | used (how would that work?) - but then again SpaceX | doesn't re-use solid state boosters either (because they | do not use any)... | | Things can be more complex and nuanced than quippy | internet back and forth suggest. That's not even touching | on the ship-of-theseus problem that is many former NASA | engineers working at SpaceX these days. | Daho0n wrote: | It doesn't really matter much because a look at the | actual numbers shows that SpaceX charge more than the | cost of launching the exact same payload would have cost | using the shuttle. Besides the reusability point is | disingenuous when talking cost since SpaceX's cost have | actually gone up per (re)launch, not down. So yes, it is | more complex than quippy internet back and forth | suggests. | | Here is a video that explains it in decent details if you | are interested, but the TL;DR is that SpaceX is more | expensive than the shuttle and way more expensive than | they said they would be: https://youtu.be/4TxkE_oYrjU | m4rtink wrote: | The SRB segments vere regularly reused, not sure about | the parachutes and the nozzle stearing gear. Still | reportedly it was more expensive to reuse the segments | (basically big metal tubes) than to build new set if SRBs | for each flight, possibly using better techniques | (monolithic carbon fibre overwrapped solid motors, like | on Ariane 5/6). | retzkek wrote: | > s far as I know no solid state boosters were ever re- | used (how would that work?) | | Nitpicking of "reuse" vs "refurbish" aside the SRBs were | significantly reused: | | > The RSRM was designed to make the most use of | recoverable hardware. The majority of metal hardware was | recycled through ATK's Clearfield refurbishment plant in | Utah and returned to a flight-qualified conditioned. | | https://ntrs.nasa.gov/citations/20120001536 | | The boosters used for the final mission, STS-135, even | included parts from STS-1! | https://spaceflightnow.com/shuttle/sts135/fdf/135srbs.pdf | smilespray wrote: | Didn't they reuse the solid rocket boosters for the | shuttle? (Granted, they were delivered by Morton Thiokol | and didn't function well in cold weather...) | [deleted] | redisman wrote: | Lets just say both are doing very important work with very | different incentives | iexplainbtc wrote: | That live stream was epic! It was great to see them so happy :) | 0_____0 wrote: | Hard for me to imagine what it's like to spend years of your | life working on a singular launch project. So much riding on | what happens in a handful of moments, whether that's launch or | EDL. Pretty sure I'd just start sobbing in the control room if | that were me regardless of outcome. | mrfusion wrote: | I thought they looked anxious and overheated. | ashton314 wrote: | Part of me is sad that I'm too young to have seen the moon | landings. But stuff like this gives me a taste of the thrill of | those days. Congratulations to everybody at NASA. Thank you for | this inspiring endeavor! | chasd00 wrote: | fricken awesome! i love being able to watch these things live. | now i have to get back to work making pixels light up at the | right time and the right color all day long. | WJW wrote: | IT LANDED! | shadowgovt wrote: | Upright and in one piece. :) No, but seriously: amazing | engineering and amazing work. So great to see the images | streaming in already. | WJW wrote: | The skycrane system is just SO COOL. It's also one of those | things that is super easy to explain but incredibly difficult | to actually construct, let alone have it work well after | flying all the way to Mars. | tnorthcutt wrote: | They're not _that_ hard to make and fly... in Kerbal Space | Program ;) | | (I'm totally kidding; what they've accomplished is | incredible!) | pupdogg wrote: | It took them approx. 4,881 hours from launch to land approx. | 127,770,000 miles away. Is it safe to say that the average speed | of the mission can be calculated as 436 miles/hour? | mikeyouse wrote: | I think you dropped a thousands somewhere.. 127.8M | miles/4,881hrs = 26,000 mph.[1] | | But in reality, it obviously didn't fly in a straight line, | Looks like it traveled closer to 292 million miles[2], so more | like 60,000 mph.[3] | | [1] - | https://www.wolframalpha.com/input/?i=127800000+miles%2F4881... | | [2] - https://mars.nasa.gov/mars2020/timeline/cruise/ | | [3] - | https://www.wolframalpha.com/input/?i=292526838+miles%2F4881... | andbberger wrote: | no. hohmann transfer, not a straight line. also there are no | absolute reference frames. | alkonaut wrote: | > also there are no absolute reference frames. | | "Well, officer, perhaps to _you_ it seemed like I was | speeding there... " | klohto wrote: | Clean feed here - https://www.youtube.com/watch?v=kPrbJ63qUc4 | | EDIT: Congrats to the team! Great success | johnohara wrote: | Reading you 5 by 5. Thank you. | distortedsignal wrote: | My personal preference is the JPL raw feed (here: | https://www.youtube.com/watch?v=kPrbJ63qUc4) but I think that | more people watching space here is better! Great link! | blach wrote: | From the JPL feed: "My computer was having trouble with Webex, | I'll restart Webex and try the visualization again." | | Hope Percy isn't running Webex. | rpiguyshy wrote: | i wish they would stream the video and audio from the craft live | as it descends to the martian surface | ryankrage77 wrote: | The bandwidth to stream video from mars simply isn't available. | Once it's landed, perserverance must lock onto sattelites | orbiting mars in order to send media back to earth. | gillytech wrote: | What an accomplishment for mankind. Congratulations to NASA, JPL | and the whole team. | m4rtink wrote: | Congratulations! | unanswered wrote: | Something I don't understand: when they say "X is 1 minute from | happening", does that mean it's really 1 minute from happening or | does that mean "in 1 minute we'll receive the signal that X has | happened"? | | Maybe my question makes more sense in the case of "X is happening | right now", because then I should either understand "we infer | that X should have happened right about now" or "we have | confirmed via signal that X has happened", and that's a big big | difference. | | I know in some cases they explicitly say the latter, so I guess | my _real_ real question is, do they just keep the communication | delay implied in all countdowns & references in discussion, to | avoid confusion? | | (ETA: No need to let me know about simultaneity problems in | relativity -- earth and mars are, relative to c and to | macroscopic time scales, essentially not moving relative to each | other AFAIK, so that simultaneity _is_ essentially well-defined. | My question was about a much more boring classical-universe | problem.) | PeterisP wrote: | It's the latter. The Earth-Mars latency at this time is | something like 11 minutes, and the landing itself takes about 7 | minutes, so when we on Earth first saw the craft entering | atmosphere on Mars, by that time all the landing was already | over, one way or another. | DiogenesKynikos wrote: | It depends on what coordinate system you're using. Simultaneity | is ill defined in relativity. There's only future, past and | "spacelike-separated" (neither past nor future). When they say, | "X is 1 minute from happening," it's actually neither in the | past nor the future. It's currently spacelike-separated, but in | 1 minute, it will be in our past. | unanswered wrote: | Yes, yes, you have shown you know what relativity is. But the | relative velocity of earth and mars -- which I can't convince | Wolfram Alpha to tell me, but it's got to be on the order of | their orbital velocity so let's say 5x10^4 mph -- is a tiny | tiny fraction of c so their inertial reference frames are | essentially identical. So sitting in our reference frame, we | _can_ make inferences about what 's happening "now" on | mars,such that these inferences are consistent (to within | that tiny fraction of c) with all of our current and future | observations in this reference frame; i.e., consistent with a | classical(+ finite speed of light) model of the universe. | Which is why I left this out of my question and only asked | about the consequences of a finite speed of light. | | Put another way, simultaneity is perfectly well defined in a | single inertial reference frame, and for purposes of my | question, earth and mars can be considered to be relatively | motionless. | colechristensen wrote: | It looked like they were quoting time as it would appear for an | earth-local observer (i.e. a million light-year away supernova | that showed up five minutes ago happened "five minutes ago" not | 1 million years and five minutes ago. | | With your personal light cone, it's fine to equate "now" with | what you see in the moment. It just has to be clear what you | mean for situations where communication might be ambiguous. If | you have a person on mars, be sure to be precise what you mean | when you tell them to do something in five minutes, when they | receive the message they won't know if you mean five minutes | after they receive the message or anywhere between 17 minutes | before and 2 minutes after they receive the message. | | When you get into relativistic speeds (and especially very | short time intervals), _nobody_ can even agree on when | something "actually" happened, different observers have | different opinions about what happens when even after you | account for light travel time. | gfiorav wrote: | Waiting for the physicist in the room to point out: there is no | such thing as simultaneity! | | :) | theNJR wrote: | Came here to suggest The Order of Time by C Rovelli, which | explains this in such a captivating way. | Sharlin wrote: | Yes, those are all Earth Receive Time, that is, when they were | saying that eg. entry interface is two minutes away, in reality | the rover was already sitting on the surface and we were just | waiting for the radio signal to get here. | unanswered wrote: | > Earth Receive Time | | Ah great, that's a great phrase to make everything clear and | provide a kind of "frame of reference" to think & communicate | in. Always need these abstractions. | OliverGilan wrote: | Doesn't relativity tell us it doesn't matter? | cjohnson318 wrote: | There's a lag time in communication due to distance. I don't | see what that has to do with relativity. | runarberg wrote: | PBS Space Time recently explained what the present time means | within general relativity[1]. As I understand it... it | matters in this context. | | [1]: https://www.youtube.com/watch?v=EagNUvNfsUI | runningmike wrote: | I never forget a great fosdem talk regarding living on mars. | https://archive.fosdem.org/2015/schedule/event/living_on_mar... | unfortunately it turned out to be a hoax. | sidcool wrote: | Touchdown confirmed!! Congrats NASA. | mu_killnine wrote: | The Nasa person they have helping narrate what's going on is so | genuinely happy the landing went well. It made me kinda tear up. | It's infectious just how excited all these people are about this | project. Also, I was a bit worried he was going to pass out. | 10/10, would watch again (and probably will with my kids) | shadowgovt wrote: | The audible _whew_ from one of the crew members after maximum | deceleration when the telemetry re-established was heart- | rending. Years of work, and there 's nothing anyone here can do | eleven light-minutes away; it was either going to work or one | of the thousands of things that had to happen correctly wasn't | going to happen. | | Everything happened correctly. :) | Azrael3000 wrote: | It's a great achievement with some really interesting work done | on the landing algorithms with terrain recognition and it seemed | to have worked exceptionally well. | | Looking forward for the next landing in May of the Chinese rover | and all the science these robots will produce. Also, the test of | Ingenuity, the helicopter, will be very interesting to watch, | that could really pave the way for a different exploration style | in the future. | | And finally, maybe the next transfer window will already see some | Starships, that would really change everything. | jaegerpicker wrote: | Ingenuity is maybe the most interesting and coolest advance for | space travel. The idea of a remote drone to explore Mars is | just rad! I can totally nerd out about that! | suyash wrote: | More about Ingenuity | https://spectrum.ieee.org/automaton/aerospace/robotic- | explor... and it's source code https://github.com/nasa/fprime | kibwen wrote: | A great video where the host visits the drone, interviews its | makers, and goes over the cool technical aspects of it and | its mission: https://m.youtube.com/watch?v=GhsZUZmJvaM | huhtenberg wrote: | First surface photo is in too! | | https://i.imgur.com/C2s1job.jpg | kaycebasques wrote: | N00b question: why is it black & white? | nwallin wrote: | Other posters have pointed out that it's the hazard avoidance | camera, but they haven't said why the hazard avoidance camera | is black and white. | | When you do computer vision, the first step you do is convert | your color image into a black and white image, and run your | CV algorithms on the black and white image. This is because | when you're looking at objects and shapes and stuff, it's | contrast that tells you where the boundaries between things | are. This is true even in a human world of human objects, | which tend to be many colored. It's even more true on Mars | where basically everything is varying shades of orange. So | having color doesn't help a whole lot, and you also have to | do the additional step of converting the color image to black | and white, which takes CPU power and adds latency. Remember, | the purpose is hazard avoidance- latency is bad. | | Additionally, color camera sensors aren't actually color | sensors. They're black and white sensors. In front of every | pixel on the black and white sensor is a filter that is | either red, green, or blue. Pixels are grouped into sets of | four, and there are two pixels with green filters, one pixel | with a blue filter, and one filter with a red filter. | (sometimes one of the green filters is omitted, giving red, | green, blue, and b&w, or sometimes one of the green filters | is a filter that allows IR, or something like that.) So if | you have a 16MP camera, the camera has 8M green, 4M red, and | 4M blue pixels. This means two things; first of all, if you | just wanted a black and white image in the first place, a | color sensor gives _less_ detail than the equivalent black | and white sensor, and second, you need to do additional | processing to convert the raw output from the sensor into an | image that 's usable for anything. The additional processing | adds latency. | whuffman wrote: | Just as a heads up, the HazCams on Perseverance are in fact | in color (Source: https://link.springer.com/article/10.1007 | /s11214-020-00765-9 - "The Mars 2020 Navcams and Hazcams | offer three primary improvements over MER and MSL. The | first improvement is an upgrade to a detector with | 3-channel, red/green/blue (RGB) color capability that will | enable better contextual imaging capabilities than the | previous engineering cameras, which only had a black/white | capability.") Your observations are correct though - the | stereo precision is important, so there was additional | analysis of the stereo depth computation to make sure it | wouldn't cause an issue. | kharak wrote: | Thank you for the explanation. That was highly interesting. | Does anyone else know if the human eye does perceive color | directly? Is this at all technically possible? And if yes, | why aren't we doing it with cameras? | POiNTx wrote: | My guess is lower image size, which means image can get | transferred faster. | txg wrote: | This is the right answer. The camera (and its 8 siblings) | are capable of color HD imaging - the sensor has a Bayer | filter. This image used a binning mode to produce a | downsampled frame that could be more rapidly transferred | back over the lower bandwidth comms used during landing. | Binning combines the Bayer pattern and so color information | is lost. | | Also doesn't help that there is a (transparent) lens cover | in front of the lens obscuring the view. | Azrael3000 wrote: | That is most certainly correct. They also mentioned that | these are images from engineering cameras, so they are | normally responsible for navigation. The real HD footage | will come in over the next hours as the bandwidth just is | not large enough. | | Elon Musk needs to provide some Starlink sats for a better | connection. | _Microft wrote: | Starlink would most certainly be of little direct use | here. | | What I could imagine is having Starlink satellites around | Mars that allow to route data from rovers anywhere on the | planet to a dedicated high-performance communications | platform that handles communication with Earth. | teraflop wrote: | In fact that's exactly what they're doing: the Mars | Reconnaissance Orbiter is serving as a communications | relay, as it did for previous landers. | | It's just that since there have never been more than a | handful of spacecraft active on Mars at any given time, | there's currently no point in spending huge amounts of | money to launch a whole constellation of satellites for | continuous coverage. | Sharlin wrote: | Not only the MRO, but other orbiting assets as well, | particularly NASA's MAVEN and ESA's TGO. Even the | venerable 2001 Mars Odyssey is still used as needed, I | think. | davidmr wrote: | And a photographer! MRO took what might be my very | favorite picture of all time: | https://www.space.com/16946-mars-rover-landing-seen-from- | spa... | m4rtink wrote: | Could be still a nice exercise if someone could compute | how many Starlinks could a Falcon Heavy throw to Mars | transfer orbit & if they could be able to actually | capture into Martian orbit by their default means of | propulsion (do they actually have any high thrust engines | ?). | nothis wrote: | Anyone know the bandwidth they're working with, at least | roughly? | kibwen wrote: | Here's a page with data about the Deep Space Network: | | https://mars.nasa.gov/msl/mission/communications/#data | | _" The data rate direct-to-Earth [from Mars] varies from | about 500 bits per second to 32,000 bits per second"_ | smilespray wrote: | It's from a hazard camera, which is not used for main | photography. Better images will come soon. | ehsankia wrote: | Worth noting that these first pictures are sent in the | first seconds after touchdown, you can even still see the | dust in the air from the landing (even if it was craned | down to reduce dust). It also explains the very low | resolution in general, they want to get confirmation ASAP, | no time for high quality high resolution images. | nerfhammer wrote: | would dust stay in the air longer or shorter than on | Earth? | | also is it technically correct to call the Martian | atmosphere "air"? | DonHopkins wrote: | Yes, but it's not technically correct to call Martian | seismic tremors "earthquakes". | | https://www.imdb.com/title/tt0080745/goofs | | Flash Gordon (1980) Goofs | | At the very beginning of the film, Ming and his henchman | are discussing "an obscure body in the SK system", which | the inhabitants refer to as the planet "Earth", | pronounced as if the word is completely foreign to them. | However, at that moment, Ming activates a button on his | console labeled "Earth Quake". | | http://bobcanada92.blogspot.com/2020/10/flash-gordon- | logic.h... | ajross wrote: | Dust falls much, much faster on Mars. The density of | Mars's surface atmosphere is ~160x lower than on Earth. | mrec wrote: | Right. One "proof" advanced by Moon landing conspiracy | theorists was that dust settled much faster in videos | than it should if it were _really_ in Lunar gravity. | js2 wrote: | Miriam Webster says yes to part two: | | > the mixture of invisible odorless tasteless gases (such | as nitrogen and oxygen) that surrounds the earth | | > also : the equivalent mix of gases on another planet | | I would naively guess yes to part one but it's | complicated: Mars has less gravity, much less atmospheric | pressure, colder temps, and greater gravitational | influence from its moons than Earth. Wikipedia says the | mechanism of the planet's dust storms isn't well | understood. | | https://en.wikipedia.org/wiki/Atmosphere_of_Mars#Dust_and | _ot... | themeiguoren wrote: | The low resolution and fuzz is also because they still | have the lens caps on - they are of course transparent | lens caps in case the explosive bolts that will release | them fail. Redundancy! | [deleted] | hiharryhere wrote: | I heard on the live stream that it was taken by a camera that | is used by the driving system. | | Guessing its black and white/high contrast to help see rocks | etc. And probably much lower res, smaller file size too for | transferring. | ijustlovemath wrote: | Just an enthusiast, no real answers, but here's a guess: | | These are hazard cameras, designed to be inputs into the | guidance algorithms on board. It might make sense for such a | camera to be B/W to reduce on board processing required. | There's also a glass cover on them, and a lot of dust from | the landing, so that may be obscuring true color if the | cameras do in fact take color images. | | Also they may have just transmitted a lower quality B/W image | to get something back to Earth quickly, since higher res | images take longer to uplink. | neals wrote: | It's an "engineering cam" that's not really meant for taking | nice pictures, more to see where the thing is going. There'll | be some better Instagram selfies soon though. | [deleted] | robinjfisher wrote: | This was explained on the feed. It's from a lower-res safety | camera mainly used for object avoidance on the ground. High | definition images will be available later. | handedness wrote: | The world is a complicated place, Hobbes.[1] | | The lower "HazCams" hazard avoidance cameras (which captured | those initial photos) are there to detect hazards (rocks, | trenches, etc.). They are stereoscopic, lightweight, and high | resolution. | | My guess is that using color sensors would have either | increased the 3D mapping precision or added | weight/power/bandwidth requirements, or otherwise been less | robust in that environment. | | Those cameras were also pre-deployed for the landing phase | and likely transmit more quickly due to the lower data | information. The other cameras were shielded for the landing | phase. | | The navigation and other cameras are in color, and I expect | we'll be seeing better images shortly. | | [1] This comes to mind whenever a question like that is | asked: http://4.bp.blogspot.com/-CWM1zDcmWXs/TroD0VsX4WI/AAAA | AAAAAV... | whuffman wrote: | FYI - the HazCams on Perseverance are in fact in color | (this is new, they were black and white on Curiosity)! | Stereo precision was a concern based on the switch to color | sensors, so there was some algorithmic work done to make | sure it wouldn't cause an issue. (Source: https://link.spri | nger.com/article/10.1007/s11214-020-00765-9 - "The Mars | 2020 Navcams and Hazcams offer three primary improvements | over MER and MSL. The first improvement is an upgrade to a | detector with 3-channel, red/green/blue (RGB) color | capability that will enable better contextual imaging | capabilities than the previous engineering cameras, which | only had a black/white capability.") | jxcl wrote: | > My guess is that using color sensors would have either | increased the 3D mapping precision or added | weight/power/bandwidth requirements, or otherwise been less | robust in that environment. | | I think you meant to say decreased? In which case I think | you would be correct! Camera pixels are made up of these | things called photosites which don't by themselves record | color, only brightness. In order to record color | information, the photosites are placed behind a Bayer | filter[1], which effectively reduces the resolution of the | camera by 3, because in order to get the color of a pixel | you need its red, green and blue component. Bayer filters | also frequently have a small blurring filter in front of | them to make sure that nearby photosites with different | color filters get the information they need. | | If you're looking for the highest resolution image | possible, black and white is the way to go! | | [1]: https://en.wikipedia.org/wiki/Bayer_filter | m4rtink wrote: | That's why "real" space cameras usually have color | filters on a carousel before the sensor - they take 3 | pictures each with different filter and BAM, color! | | That way you get high regulation as well as color. You | can also have some special (infrared, ultraviolet, etc.) | Filters on the carousel, not just RGB. | kube-system wrote: | Here's the answer from NASA: | https://youtu.be/gm0b_ijaYMQ?t=6240 | ArtWomb wrote: | Greetings from Jezero Crater! Really doesn't look alien. RLike | the high mesa of New Mexico sans flora ;) | gillytech wrote: | The shadow features are fantastic! | ortusdux wrote: | They have a live telemetry animation web app, but I am currently | getting a 503 from cloudfront. | | https://eyes.nasa.gov/apps/mars2020/ | shadowgovt wrote: | Yeah, it was accessible until they mentioned it in the | livestream. | | To their credit, I've watched NASA spend decades getting better | at Internet services and generally being an online presence. | Improvements year-over-year have been noteworthy. But I still | have to chuckle a little bit that they triggered a DDOS protect | by name-dropping themselves. | | Ad Internet Per Aspera, you crazy spacers ;) | raylus wrote: | Thanks!! Also wanted to mention, NASA is separate from JPL | for the most part as far as web services go. | shadowgovt wrote: | Great work today. | mhh__ wrote: | The telemetry they have up on the wall is based off a project | that they have open sourced too (Open MCT), or at least it | looks like it. | alach11 wrote: | Watching the stream, it's striking the difference in employee age | between NASA and SpaceX. I won't speculate on the reasons, but I | wish the best to the Perseverance team! | shironandon wrote: | unsure why you think that is relevant, bub. Interested in their | religion, political views, and sexual preferences as well? | klohto wrote: | Stop picking up fights, that wasn't the point of the comment | at all. | johnchristopher wrote: | I thought they were young people in the NASA video. Does that | mean people at SpaceX are older ? | flyinglizard wrote: | It's also remarkable that the NASA workforce is 99% women, as | evident from this broadcast. | dharmab wrote: | Remember that not all the staff could be at NASA today due to | COVID policies. Most of the team is at home. | avereveard wrote: | I don't think the video show a representative sample of the | employee at either company; I suspect picks where selected for | stage presence with a touch of preference for diversity. | tambourine_man wrote: | https://www.youtube.com/watch?v=gm0b_ijaYMQ | | Live feed | ggm wrote: | Here in oz its not live | meepmorp wrote: | I guess technically it's on an 11 minute delay for the whole | planet. | ggm wrote: | Well yes, but I meant I watched continuously from 06:45 to | 07:15 and it was replay of pre-recorded videos of the rover | and no indication on screen it had landed. | rablackburn wrote: | odd, I'm in Aus too and I watched the entire thing live | with no issues (assuming you're in QLD on EST) | ggm wrote: | I am. Maybe I turned away at the wrong crucial 30 | seconds. | | (Edit) I checked the JPL clean feed and none of the last | two hours of feed is what I saw being sent on NASA live. | I got a walk around the robot, and social media about the | kids who named it, and talking heads. Bizarre. | jaegerpicker wrote: | Seeing the engineers and scientists celebrating the successful | landing was one the best things I've seen in a LONG while. Very | live affirming and inspiring to me! | BurningFrog wrote: | Is part of the joy that they now have secure jobs for years to | come? | AnimalMuppet wrote: | I think it's mostly the joy that their past decade or two of | work wasn't wasted. | jaegerpicker wrote: | Maybe but for me I think it would the joy of completing such | a massive task so well. They literally just achieved | something that no one else in history has. | Rebelgecko wrote: | I wouldn't be surprised if a lot of the engineers who worked | on EDL move on to other projects in the coming weeks | notum wrote: | Any JPL/NASA HN users that could comment? That would be beyond | awesome! | | Great job, mission! | raylus wrote: | JPL Engineer here, any questions I could convey to the slack | I'll be glad to feed back to HN | prox wrote: | I just want to thank you all for the wonderful time tonight, | we've been watching with the family. Amazing accomplishment! | vagrantJin wrote: | Sick! | | Will this rover make contact with its forebears at some | point? | krysp wrote: | Awesome achievement! What was the part of the mission you | were most concerned about / most likely to go wrong? | michaelt wrote: | Awesome stuff. | | I couldn't help but wonder, while I watched the feed: What | are the people in mission control doing during the landing? | | Obviously they're monitoring telemetry - but what else? | Presumably the time delay precludes them triggering anything | critical manually, and making post-launch software changes | would be frowned upon? | helmholtz wrote: | They're all going to get wasted tonight, mate. | throwawaygimp wrote: | thats Mars 'tonight', of course | fetacheese wrote: | I have serious doubts that this actually happened | chrononaut wrote: | I included this the other day in the previous Perseverance thread | but if you're excited for the Perseverance EDL video hopefully | Doug Ellison's composite video of Curiosity's landing (from a | single camera) can tie folks over in the mean time! | https://www.youtube.com/watch?v=RZioPhfxnSY | pjfin123 wrote: | Exciting time to be alive! ___________________________________________________________________ (page generated 2021-02-18 23:00 UTC)