[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!
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