13 ms·

Athena landed in a dark crater where the temperature was -280° F / -173° C

231 points by 01-_- 2y ago

1970-01-01 2y ago
Still unclear what happened. Did they not anticipate a big moon hole or did navigation fail when the rangefinder failed?
- ceejayoz 2y ago
  I'm not sure what you find unclear. Navigation was fine - "Athena knew where it was relative to the surface of the Moon" - but without a working altimeter it was kinda fucked for actually touching down. Hard landing, skid, tip.
  - walrus01 2y ago
    Was there no functioning laser or radar altimeter for the final descent phase?
    - ceejayoz 2y ago
      "However, the lander's altimeter had failed."
      - 1970-01-01 2y ago
        Looking at this closely, it was working, however it was noisy. I speculate that they didn't correctly anticipate the moon dust problem. Laser rangefinders may not be a workable solution for future landings. So engineers at Intuitive Machines had checked, and re-checked, the laser-based altimeters on Athena. When the lander got down within about 30 km of the lunar surface, they tested the rangefinders again. Worryingly, there was some noise in the readings as the laser bounced off the Moon. However, the engineers had reason to believe that, maybe, the readings would improve as the spacecraft got nearer to the surface. https://arstechnica.com/space/2025/03/intuitive-machines-second-attempt-to-land-on-the-moon-also-went-sideways/ https://arstechnica.com/space/2025/03/intuitive-machines-sec... https://www.space.com/nasa-moon-landing-dust-concerns.html https://www.space.com/nasa-moon-landing-dust-concerns.html https://en.wikipedia.org/wiki/Lunar_horizon_glow https://en.wikipedia.org/wiki/Lunar_horizon_glow
        ceejayoz 2y ago
        Noise at 30km altitude probably points more towards a sensor issue than dust.
        Aspos 2y ago
        May it be that laser bounced off exhaust plume?
        lightedman 2y ago
        I think it would be unlikely that a plume was caused from 30km away on something with no atmosphere.
        echoangle 2y ago
        Unless their processing is very weird, that shouldn’t be the issue. You send a pulse and record the output of a detector to listen for the reflection. If the laser is reflected at the plume, you should get some pulses very quickly, but also faint and spread out in time, which you would be able to tune out. And the real response from the ground should be more narrow because it’s reflecting at a single distance. If very short range noise influences the signal when measuring 30km real distance, you’re doing something wrong.
        inamberclad 2y ago
        Laser is angled outwards at approx 45 degrees, I think it's well away from the exhaust plume.
        numpad0 2y ago
        LRFs and radars on the Moon has been fine for a long time, it can also be angled away from gravity axis and multiplied by sine theta if needed.
  - 1970-01-01 2y ago
    If navigation was fine, why was touchdown on a plateau?
    - ceejayoz 2y ago
      Because "where am I" and "how high am I over that position" are very different things. Visual demonstration of being at the wrong altitude in the right spot: https://www.f-16.net/f-16-news-article968.html https://www.f-16.net/f-16-news-article968.html
      - deleted 2y ago
        [deleted]
      - echoangle 2y ago
        If you don’t know your altitude, navigation isn’t fine though. Navigation should give you a position in all axes.
  - JshWright 2y ago
    The top-heavy design didn't help things either. I'll be shocked if they don't go three-for-three on landing sideways given IM3 has the same tall design.
    - ceejayoz 2y ago
      The company claims it's not as top-heavy as you'd think from pics: https://www.theregister.com/2025/03/07/intuitive_machines_landing/ https://www.theregister.com/2025/03/07/intuitive_machines_la... > At his press conference earlier today, Altemus defended the design, saying the spacecraft doesn’t have a high center of gravity because most of its cargo attaches to the base of the vehicle. He said there were no plans for a radical rethink of his company's design. (We see this in returning F9 first stages, as well.)
    - sandworm101 2y ago
      >> The top-heavy design didn't help things either Just wait for SpaceX to start trying to land starships on the moon. Also vertically. Also doomed to tip over whenever the surface is slightly out of spec. https://www.spacex.com/humanspaceflight/moon/ https://www.spacex.com/humanspaceflight/moon/
      - JumpCrisscross 2y ago
        > Just wait for SpaceX to start trying to land starships on the moon. Also vertically SpaceX has done it. To date, other nation-states have tried and failed to replicate their achievements in this domain. IM’s design is wrongly optimised and probably requires a rethink. That the CEO won’t contemplate this isn’t a great sign for the company.
        CamperBob2 2y ago
        SpaceX has done it. SpaceX has landed Starship on the moon?!
        JumpCrisscross 2y ago
  - nomel 2y ago
    > "Athena knew where it was relative to the surface of the Moon" - but without a working altimeter it was kinda fucked for actually touching down. Z is an axis that exists in our 3d world, and a required value for any relative position, which means it DID NOT know where it was, relative to the moon.
    - PantaloonFlames 2y ago
      Ya the wording was not quite … satisfactory. I think they meant , it could tell X and Y, but not Z. But all three are important. Related - I’m not clear how the article can describe that landing as “not crashing”. If that was not a crash, what was it? Will they call it a crash only if there are Hollywood-style explosions?
      - jacobgkau 2y ago
        Bringing "Hollywood-style explosions" into it is a little much. If you slam the breaks on in your car, your tires hit some debris in the road, and you spin around and end up somewhere you didn't intend to be, but the car wasn't meaningfully damaged (i.e. you didn't hit other cars or manmade structures), you made a dangerous uncontrolled maneuver, but you didn't crash. That seems more like how they're describing this "skid." Relevantly, it sounds like this lunar spacecraft was still functioning after the hard (non-)landing. The only reason it died after that was because of debris settling on the solar panels, which made it run out of power.
        PhasmaFelis 2y ago
        If you do something with your car that ends up with it skidding on its side, that's a crash by any possible definition.
        jacobgkau 2y ago
        Probably, but this is a space probe, not a car. It's lighter than a car, and is operating in an environment with less gravity.
  - meindnoch 2y ago
    But if they knew where it was relative to the surface of the Moon, they could have subtracted that from where it wasn't, or where it wasn't from where it was (whichever is greater), to obtain a difference, or deviation. The guidance subsystem could then use deviations to generate corrective commands to drive the missile from a position where it was to a position where it wasn't.
- martin_drapeau 2y ago
  Scott Manley has a great video explaining what he thinks happened. https://youtu.be/ISZTTEtHcTg?si=0LZFyiCysBiFZrMz https://youtu.be/ISZTTEtHcTg?si=0LZFyiCysBiFZrMz
  - 1970-01-01 2y ago
    Scott Manley and I agree that altitude signal shouldn't matter if navigation is correct. Athena simply risked touchdown, and it didn't find a flat spot, it found a hole. https://youtu.be/ISZTTEtHcTg&t=1158 https://youtu.be/ISZTTEtHcTg&t=1158
    - ceejayoz 2y ago
      Can you quote the bit you think is relevant here? He's saying modern spacecraft can null out the horizontal velocity to land, but without an altimeter, you don't necessarily know when to do so, nor when to give the thrusters a little boost to avoid an obstacle you're about to hit, like a plateau.
  - numpad0 2y ago
    tldw: speculation: landed with too much lateral velocity and one of legs broke
  - someothherguyy 2y ago
    Does anyone know an extension that strips this tracking information and normalizes YouTube URLs?
    - tennox 2y ago
      There's tons... Firefox: https://addons.mozilla.org/en-US/firefox/addon/clearurls/ https://addons.mozilla.org/en-US/firefox/addon/clearurls/ Android: https://github.com/svenjacobs/leon https://github.com/svenjacobs/leon
    - wruza 2y ago
      Just in case, I’m using my own violentmonkey scripts rather than hoping for extensions, and everyone can do that too (now only on firefox, I guess, and maybe brave). For example, I remove &t=<n> from urls that youtube added recently in addition to regular watch position restoration. This broke it for me and they don’t seem to plan a revert.
- russdill 2y ago
  It touched down with a large horizontal velocity component
  - PantaloonFlames 2y ago
    That’s another thing that bothered me about this story. They said they knew where the craft was , relative to the surface of the moon. Wouldn’t that also mean they should know of any substantial horizontal (x/y) component of velocity?
    - gtirloni 2y ago
      Yes, through image analysis.
    - marcosdumay 2y ago
      I don't know if it's the case, but there's a difference between knowing something and calculating its derivative fast enough for it to be useful.
bell-cot 2y ago
At what point do you just fire your entire "Land on Moon" software team, and hire a couple young Neil Armstrong wanna-be's, who can hand-land your spacecraft remotely? (In spite of the moon-earth-moon signal lag.)
- ceejayoz 2y ago
  You’d probably wanna make sure that’s the problem area first. Considering the altimeter failed, that seems unlikely to be the case.
- PantaloonFlames 2y ago
  In this domain, Signal lag seems to be an insurmountable problem, when using remote control. 2.7s delay will be hard to mitigate in a dynamic system. Unless I am misunderstanding something.
  - nottorp 2y ago
    They could hire MMO players from areas with crap ping to the servers :)
dist-epoch 2y ago
Dumb question, but why can't it have a few simple telescopic sticks which extend to flip it over if it lands upside down. Seems it's the second time they fail in this mode.
- ragebol 2y ago
  Moe parts, more complexity, more weight.
- hulitu 2y ago
  Because: 1. It cannot fail in this mode. 2. Testing is done by the user, test results are sent by telemetry and the fix will be done, when the bug can be reproduced on developer's computers. /s
- somenameforme 2y ago
  Definitely not a dumb question. The first lander to land on the Moon (after many failures) is pretty amusing. [1] The Soviets a designed a lander that'd be launched right into the Moon but, just before impact would jettison the lander which itself was a highly reinforced ball that was then designed to simply pound into the Moon at 54kph, but survive the crash. The egg then unfurled and finally humanity had achieved a 'soft' landing on the Moon. Somehow it kind of makes one think of a really elaborate egg drop contest paired with a 'what happens if you jump right before the elevator crashes.' Like another comment mentioned, complexity and size are big issues. Some more are power/mechanics (fluids, such as for hydraulics, and -280F aren't gonna play well together) and then there's the fact that there's not even a guarantee it'd work. Your legs could get damaged, you might end up in an orientation where none of the legs are appropriate, and so on. So you may be adding a whole bunch of complexity for stuff that might not even save you in the situation it was designed for! [1] - https://en.wikipedia.org/wiki/Luna_9 https://en.wikipedia.org/wiki/Luna_9
- notTooFarGone 2y ago
  battlebots did it first!
- mystified5016 2y ago
  Mass. Each kilogram costs what, millions? Hundreds of millions? There's a small chance that navigation or landing fails in a way that would make those legs useful, and an even smaller chance that they'll save the mission. Given tight budgets, this is almost certainly not a gamble worth taking
areoform 2y ago
If you take the time to study the documentation from the 1950s & 1960s, the engineering culture of that era appears to be markedly different from the engineering culture prevalent today. And I think it's deeply rooted in the symbiotic relationship between computing, Baumol's cost disease and our obsession with precision, results-oriented, MBA-style-min-maxing, "good enough for government work" engineering. Robert Truax, the designer of the Sea Dragon, loved to promote the design paradigm of Big Dumb Boosters. Instead of many small, sophisticated rocket engines, what if we made one big robust one that can take a lickin' and keep on kickin'. The idea was to relax the mass margins and to create big. dumb. boosters. It's the approach TRW explicitly followed for the Lunar Module engine, > "There was an amusing but instructive side to this program. TRW farmed-out the fabrication of the engine and its supporting structure, less the injector that they fabricated themselves, to a "job-shop" commercial steel fabricator located near their facility . The contract price was $ 8000. Two TRW executives visited the facility to observe the fabrication process. They found only one individual working on the hardware, and when queried, he did not know nor care that he was building an aerospace rocket engine." > " I had arrived late to witness the test, and only saw the firing. I was told by others who witnessed the entire test procedure that the engine was pulled out of outdoor storage where it lay unprotected against the elements. Before it was placed on the launch stand, the test crew dusted off the desert sand that had clung to it. This unplanned inlcusion [sic] of a bit of an environmental test also demonstrated hardware ruggedness of the kind no other liquid rocket eingine [sic] could approach." The Surveyor program managed to make it "just work" 5 out of 7 times by adopting this approach. It had robust landing legs and RADAR. They would decelerate and then shut off the engine 11' above the surface. The wide, sturdy legs would then absorb that final impact of coming stand still from free fall. These programs had a lot of capital behind them. Some components required precision engineering, but there's a very clear through line and embrace of the "we gotta make stuff that can take a lickin' & keeps kickin'" philosophy. Modern engineering approaches seem to be the opposite of that. I think we've become so accustomed to living in a silicon driven world where our personal devices are engineered at microscopic level that we've forgotten how to do things the Apollo-era way. For example, to the best of my knowledge, IM-2 doesn't use RADAR — they're using LIDAR and optical navigation instead. Perhaps it is to save on mass and power so that more payload reaches the surface. Perhaps optical navigation was declared to be "good enough." Perhaps it doesn't make sense from a minmaxing of capital perspective. But this philosophy may not be suited to an untamed frontier. China adopted the Surveyor / Apollo-era philosophy. Their first successful lander, Chang'e 3, used the same hover & fall technique as Surveyor. > The vehicle will hover at this altitude, moving horizontally under its own guidance to avoid obstacles, and then slowly descend to 4 m above the ground, at which point its engine will shut down for a free-fall onto the lunar surface. The landing site will be at Sinus Iridum, at a latitude of 44º. It chose the terminal landing sites with the help of LIDAR and its cameras, but it relied on RADAR and a suite of sensors to have robust navigation. The follow up missions up-ed the ante every time, but they seem to have consistently focused on the robustness of their craft over precision, MBA-spreadsheet-oriented minmax-ing.
ck2 2y ago
Kinda explain why Neil Armstrong burned up all their fuel except for a few seconds scoping out the landing site in paranoia. Instead of building all these expensive to launch big landers, why not get some pizza-box sized probes into earth orbit AND THEN do like a slo-mo golf shot arcing to where the moon will be for a super slow/soft landing? Some will fail but if you launch 100 and get 20-30 working, there you go. As technology progresses, get it down to a shoe-box sized probe and then in 10 years smartphone sized (in 100 years tic-tac sized).
- btbuildem 2y ago
  Combine that with leaving the long-range comms (and higher-powered equipment) in lunar orbit as the "master" for all the probes scattered on the surface, and maybe the problem becomes simpler by breaking it in two.
- mapt 2y ago
  Space applications of all sorts are screaming out for mass production approaches. With so much design work and verification the actual manufacturing cost tends to be trivial by comparison, the work readily adapted to concurrent manufacturing processes.
  - AStonesThrow 2y ago
    When I signed on to a Mars mission in 1999, the scientists told me that’s JPL’s approach: instead of extremely expensive, robust, redundant craft, they would begin to make leaner stuff and worry less when it failed... Around the same time, Mission Control was replacing their bespoke hardware with COTS and trying to minimize the “glue” HW/SW for space systems. You'll also see that expertise on a particular instrument package is leveraged over and over across multiple missions. NASA still has amazing educational outreach and makes incredible software, even for mere mortals.
- accrual 2y ago
  It's definitely possible to target a certain surface location on the moon from low Earth orbit and set off on a trajectory to get there with a single burn. However, as the craft(s) approach the moon and enter its sphere of influence, gravity will kick in and increase their relative velocity to the surface. Another burn (suicide burn if you're feeling lucky) would be needed for the soft touchdown. The moon is also gravitationally very "lumpy", so some small corrections might be needed along the way as well.
1970-01-01 2y ago
Here's the hole it fell into: https://www.lroc.asu.edu/images/1408 https://www.lroc.asu.edu/images/1408
- CarRamrod 2y ago
  There's a mote on the crack on the Mössbauer spectrometer on the instrument arm on the rover in the hole in the bottom of the sea of tranquility
- freeopinion 2y ago
  Great shoutout to Arizona State University for the images. I like to see when someone or some group gets some recognition for work they have performed in relative obscurity for a very long time. Years of craft, getting better and better at something most don't bother with. Then suddenly your expertise gets a spotlight in a meaningful way. (Yes, I suppose there are many other sources that could provide images. These happen to be from ASU.)
dang 2y ago
Related. Others? Athena spacecraft declared dead after toppling over on moon - https://news.ycombinator.com/item?id=43292471 https://news.ycombinator.com/item?id=43292471 - March 2025 (340 comments) The Moon Lander Athena's Fate on the Lunar Surface Is Uncertain - https://news.ycombinator.com/item?id=43283136 https://news.ycombinator.com/item?id=43283136 - March 2025 (1 comment)
Koshkin 2y ago
https://en.wikipedia.org/wiki/IM-2 https://en.wikipedia.org/wiki/IM-2
littlestymaar 2y ago
Can someone ELI5 why it's at that temperature? I mean, because it's in the dark I'd expect it to reach equilibrium with space background thermal radiation which is around 3K. Yet its 100K. Where does that heat comes from? It radiates from earth? Conduct through the floor coming from the inner of the moon itself? (Is there some kind of geothermal gradient on the moon BTW?)
- antonvs 2y ago
  There are multiple factors. The biggest ones are reflected sunlight; infrared and thermal conduction from surrounding rocks; and the Moon's internal heat (the region between the core and the mantle has a temperature of over 1,300 C).
  - kQq9oHeAz6wLLS 2y ago
    Also, little atmosphere means the sun doesn't heat up the area like in your house. Once you're out of the sunlight, it's darn cold.
    - littlestymaar 2y ago
      The question isn't “why is it cold” but the opposite “why is it so hot” (100K when the universe radiation is 3K)
shadowgovt 2y ago
> As a result, the privately built spacecraft struck the lunar surface on a plateau, toppled over, and began to skid across the surface. As it did so, the lander rotated at least once or twice before coming to a stop in a small, shadowed crater. Oh yeah, we've all Kerbaled it in like that at one point or another.
dang 2y ago
[stub for offtopicness]
- ThePowerOfFuet 2y ago
  -173°C.
  - oneshtein 2y ago
    100K
    - muzani 2y ago
      This actually puts it into perspective, knowing it's closer to absolute zero than room temperature.
      - layer8 2y ago
        It’s roughly a third of room temperature.
        dietr1ch 2y ago
        Which is hard to grok since a third of something warm doesn't seem to be extremely cold.
        layer8 2y ago
        It’s sort-of the point to realize that it actually is (a third of something). The lander is receiving a third of the thermal energy that it would receive at room temperature. Warm-blooded mammals of course have a reference point based on their thermal homeostatic capabilities (ability to maintain body temperature). “Warm” and “cold” is in relation to that.
        ted_dunning 2y ago
accrual 2y ago
> For the second mission in a row, the lander's altimeter failed That's a bummer. Altimeters are relatively simple and defined hardware as far as I know. Send a ping, receive a ping, calculate. Too bad they didn't incorporate a backup solution.
aaron695 2y ago
[dead]
driggs 2y ago
Is there any sort of international body with regulatory power over the moon, or is it completely lawless and unrestricted? This startup has already crashed two pieces of space junk onto the lunar surface. Can any startup able to get there do whatever they want?
- kQq9oHeAz6wLLS 2y ago
  Well, there's a natural barrier to entry, i.e. it costs millions on dollars and years of time to be able to "crash" your "junk" onto the surface. So it's not like a bunch of hobby rocketeers are throwing away their McDonald's garbage. By the way, in comparison to the cost and complexity of said "junk", everything you own is cluttering up the Earth. You should really do something about that.
  - driggs 2y ago
    Are you making the argument that anyone with enough money should be able to do whatever they want on the moon? Giant neon McDonalds billboards visible from everywhere on Earth? Mining with zero restriction on impacts to the surface of the Moon or its atmosphere? Apparently the HN crowd doesn't stand anyone criticizing a "startup", but I'm asking a legitimate question. So far most of the junk we've launched onto the Moon has been in the name of science and operated by nations. An assault by the Free Market is unprecedented. I'm asking a legitimate question about regulation, and implying a question about whether regulation is warranted.
    - kQq9oHeAz6wLLS 2y ago
      > Are you making the argument that anyone with enough money should be able to do whatever they want on the moon? No, I'm making the argument that anyone who invests the time and money into landing on the moon isn't doing it for giggles and the joy of littering. And let's be real, if we found "space junk" on the moon of an alien planet, we'd be thrilled as heck, so perhaps we're just seeding the moon with artifacts for alien races.
    - elzbardico 2y ago
ghostly_s 2y ago
This company's PR team is doing incredible work getting all this type of coverage out of a 0/2 track record with a design everyone else seems to think is obviously flawed.
- Waterluvian 2y ago
  What’s the prevailing criticism? High COG?
  - JonChesterfield 2y ago
    It's tall and narrow and falls over when it hits the ground moving fast. Irritating for intuitive machines whose stance is that mass is not uniformly distributed and center of mass is already low enough to make flight control somewhat challenging. The criticism should perhaps be that the laser range finders are clearly a liability and a robust/workable backup for telling how far away the ground is needs to be brought along.
- pdf2calguy 2y ago
  hey man we made it on the rock and checked the weather thats cool right
yieldcrv 2y ago
> this mission was largely a success. What can he possibly mean by that? > Compared to the company's first spacecraft, Athena flew smoothly. Reminds me of the comedian opining on the flipped over airplane. “Did you know the pilot was a woman? [hecklers] Woah woah, I’m not saying women cant be pilots, thats not even accurate. She flew perfectly….. what I am saying is that she can’t drive”
deleted 2y ago
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ivanjermakov 2y ago
Why people make temperature in space a big deal? It's mostly vacuum and has no heat capacity. Sun radiation is the real threat, but the concept of temperature can't even be applied to vacuum.
- rtkwe 2y ago
  The ground it's laying on though does though.
- elzbardico 2y ago
  The space surrounding you may not have a temperature but your spacecraft does, and it will lose heat via radiation, batteries and electronics will stop working after your temperature reaches a certain low.
  - kortilla 2y ago
    Any moderately active satellite has far more issues with excess heat
    - snewman 2y ago
      The article clearly states that providing enough power to run the heaters was one of the challenges that led to the death of the probe. Satellites are rarely in the shade for an extended period.
    - verzali 2y ago
      It depends on the size of the satellite and its power use. Small spacecraft often don't use enough power to generate enough heat to warm themselves. The problem then is batteries get cold (which is one of the places you need heaters) and become inefficient and then you end up in death spiral. Here the probe likely wasn't generating enough power anyway, so that would almost certainly kill it before the cold.
      - dredmorbius 2y ago
        The problem is less the quantity of heat generated than of shedding that heat. Even modest electronics emit several watts of thermal waste heat, and given that the entire satellite is in a highly-insulating vacuum, as well as subject to solar insolation (at 1 kW/m²), it's easy to exceed thermal budgets.
behnamoh 2y ago
the second pic reminded me of the pale blue dot... it's a long way from home...
hilbert42 2y ago
This is horribly disappointing but I'm surprised the altimeter failed as I'd have thought this would have been one of the more reliable aspects of the mission. How does its altimeter work, exactly what tech does it use? It's worth remembering that radar-type altimeters have been around for a long time and are well developed. For example, Little Boy that was dropped on Hiroshima 80 years ago used radar altimeters in a redundancy arrangement (four devices) and that worked on first attempt. So what went wrong? Second question, was redundancy employed in the altimeter's design? Third, if the altimeter employed redundancy then why weren't its multiple sections of different designs to allow for the possibility that the reflected signal may be weak and noisy? (The strength of a returned wave from a radar transmission depends on various factors including its wavelength and the properties of the surface it's being reflected from. If there's any doubt the returned signal's S/N would be such that noise could be a problem it'd make sense for a redundant system to employ multiple wavelengths whose frequencies are far enough apart to take advantage of the fact that the moon's surface would reflect different wavelengths in different ways and at different signal strengths.)
virgildotcodes 2y ago
To be clear, I am in no way a conspiracy theorist, at all. Seriously, not just a bs disclaimer. That said, all of the recent photos of the moon that have come out in the last month or so look, to my eye, super CGI. Just uh, overly smooth and lacking in detail? Is there a reason for this or am I just tripping?
- marcusverus 2y ago
  There is no atmosphere, ergo no light diffusion. Shadows will be crisper, lit spots will be brighter, dark spots darker. It makes sense that such differences could make an image feel "off".
- alex_young 2y ago
  I’m not sure I get it. Can’t you just look at it yourself? It seems pretty real to me.
- bbor 2y ago
  What other pictures are you thinking of? I don’t recall any rovers since china’s (?) last year. These pictures in particular are taken from a very high altitude, which may explain why they look unnatural?
TimByte 2y ago
Space is one of those rare fields where partial success actually counts as genuine progress.
- wesselbindt 2y ago
  Exactly. I look forward to humanity genuinely progressing towards successfully landing stuff on the moon. One day, we may even be able to land humans there! Intuitive systems is really pushing the envelope here, and I think that's worthy of admiration.
deleted 2y ago
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lionkor 2y ago
the altimeter? Surely you would put three on there?
- mattlondon 2y ago
  +1 They had the altimeter fail on the previous mission too. Seems like a fairly crucial component of a moon lander. Armchair rocket scientist here, but if I were on that engineering team I'd lobby hard for less science payloads and more backups for critical instruments for the actual flight of the craft. The rover and hopper and drill etc all sound cool yes, but worthless if you can't land. Again. For the second time. Because the same critical component failed, again. With apparently no backup, again. Of course, it sounds so simple. I am sure there is more to it (e.g. perhaps they had backups and everything worked, but they just weren't fit for purpose?)
  - T-A 2y ago
    > They had the altimeter fail on the previous mission too. Not really. They forgot to toggle the safety switch on before launch, so the laser could not be used: https://spaceq.ca/simple-error-could-have-resulted-in-intuitive-machines-mission-failure/ https://spaceq.ca/simple-error-could-have-resulted-in-intuit...
- JonChesterfield 2y ago
  Had two. One showed so much measurement noise they couldn't trust it, other kept cutting out. Not great.
  - lionkor 2y ago
    So three ones, two different models, one in a different location. These are like... basics, no?
    - ricardobeat 2y ago
      If you multiply every critical component by 3x there will be no room left for anything else.
jiggawatts 2y ago
Scott Manley put together a great analysis of why it tipped over: https://youtu.be/ISZTTEtHcTg https://youtu.be/ISZTTEtHcTg TL;DW: It had far too much sideways velocity immediately before touchdown, likely due to some guidance-system failure. It would have crashed even if it was crab-shaped instead of tower-shaped.
jmmcd 2y ago
> The Athena spacecraft was not exactly flying blind as it approached the lunar surface one week ago. The software on board did a credible job of recognizing nearby craters, even with elongated shadows over the terrain. However, the lander's altimeter had failed. > So while Athena knew where it was relative to the surface of the Moon, the lander did not know how far it was above the surface. This is really crappy writing. That second paragraph sounds like a self-contradiction. Unless "the lander" is a separate entity from "Athena"? Some publications refuse to use the same term twice, even if it introduces ambiguity as here.
- EGG_CREAM 2y ago
  In their defense, using Athena again here would have definitely sounded strange and not natural. But, they could have used the word “it” without introducing ambiguity, which they do 2 times already.
- randallsquared 2y ago
  It knew where it was selenographically, which is what the author means by "relative to the surface of the moon", I think.
- kryogen1c 2y ago
  > That second paragraph sounds like a self-contradiction Aside from the point you made, it actually IS a contradiction. Paraphrased: >> Athena knew where it was relative to the surface of the Moon, but Athena did not know how far it was above the surface of the moon. Relative position includes height/altitude? One understands from context, but this sentence does not carry meaning itself.
  - HenryBemis 2y ago
    I read this and I thought it was a bad writing, and I assumed (right or wrong) that (metaphor ensues): The airplane's pilot could see where the ground was and he estimated it was 1000m-1200m below. But the instrument of the airplane were malfunctioning and reported that the ground was at 500m (or 5000m). This caused the plane to override/resist the pilot's manual landing efforts causing the plane to ultimately crash but not allowing the wheels to come down and the flaps to do turn. So two different mechanisms, providing contradicting evidence, and the lack of a 'higher' deciding authority to use 'judgment' and/or other inputs to 'decide' which reported measurements are more accurate, and thus make the viable decision/take the viable action. I get that for such devices every-gram-counts, and perhaps from now on some devices/mechanisms that are truly single-points-of-failure, will get 2x or 3x for redundancy/contingencies. If your ABC-camera fails, it's 'ok' you can still get images from your DEF and GHI will give you some data, reducing to 80% the output of the mission, but still not making it 5%. Your 'landing equipment' fails, and you get out only 5% of the value (flying/trajectory/telemetry of flight/perhaps some eclipse photos).
Aerroon 2y ago
Is there any reason why we couldn't have some rudimentary GPS-like satellites around the moon? That could help out these kinds of landers, no?
- freeopinion 2y ago
  Who do you propose should fund lunar GPS for the benefit of private companies who want to land on the moon?
  - krisoft 2y ago
    The private companies. But “who should fund this?” is a separate question from “would this help?”. I don’t think it would really help that much, and that is the reason why the private companies are not doing it.
- tliltocatl 2y ago
  High lunar orbits is unstable because of Earth influence (i. e. long-term orbiting requires lots of fuel for extensive orbit maintenance). Most low orbits are unstable as well because of uneven mass distribution, but there are some exceptions: https://en.wikipedia.org/wiki/Frozen_orbit https://en.wikipedia.org/wiki/Frozen_orbit Low orbits would also require either more satellites for complete coverage or synchronizing launch window, which is PITA enough as it is now.
  - scoofy 2y ago
    But would they need to be in the orbit? Since nothing is on the moon, couldn't you just create a GPS array on the ground?
    - addaon 2y ago
      For a GNSS-type system to work, you need four transmitters in sight. This would imply a moderately dense ground network on the moon for a receiver at orbital height -- and as this article points out, we're not doing great at building even a spare ground network of right-side-up transmitters right now -- but would need increasing density for a descending receiver. We don't really have challenges right now with accurately determining orbital parameters of probes above the moon, it's the final few miles where GNSS-level accuracy would be tempting; but that's also the domain where seeing four ground-based transmitters is basically impossible.
inamberclad 2y ago
Welp, I worked on this one. Specifically, I worked on the laser rangefinders which are under so much scrutiny. I no longer work at Intuitive Machines, but I'm certainly interested in finding out what happened to the lasers this time.
- yieldcrv 2y ago
  some of the comments here are suggesting the lander chose that spot, as opposed to crashing and skidding across the surface before settling in the spot purely due to inertia, what's the merit to that?
  - inamberclad 2y ago
    I did not work on the HDA algorithm which is responsible for landing site deviation, but this technology was inherited from NASA's Project Morpheus, which could intelligently detect hazards and divert to safer sites.
- krisoft 2y ago
  Ooo. Not sure if you can tell us anything. If you can’t I totally understand. But in case you can: Was a radar based altimeter considered? How do you guys deal with kicked up regolith? (I have seen first hand how hard heavy snow is on lidars, and would imagine that regolith “shower” is similar, but what do I know.)
  - inamberclad 2y ago
    The lasers are smaller and lighter than most radar systems. They're also pointed out at about 45 degrees from the lander and they're not supposed to be used for the last few dozen meters of descent.
    - krisoft 2y ago
      Thank you!
throway456aef 2y ago
[dead]
villmann 2y ago
How can you have temperature without a medium? The lander would have steadily lost temperature through heat radiation, but it's not like the vacuum had a temperature in the crater.

231 points by 01-_- 2y ago

1970-01-01 2y ago

Still unclear what happened. Did they not anticipate a big moon hole or did navigation fail when the rangefinder failed?

ceejayoz 2y ago
I'm not sure what you find unclear. Navigation was fine - "Athena knew where it was relative to the surface of the Moon" - but without a working altimeter it was kinda fucked for actually touching down. Hard landing, skid, tip.
- walrus01 2y ago
  Was there no functioning laser or radar altimeter for the final descent phase?
  - ceejayoz 2y ago
    "However, the lander's altimeter had failed."
    - 1970-01-01 2y ago
      Looking at this closely, it was working, however it was noisy. I speculate that they didn't correctly anticipate the moon dust problem. Laser rangefinders may not be a workable solution for future landings. So engineers at Intuitive Machines had checked, and re-checked, the laser-based altimeters on Athena. When the lander got down within about 30 km of the lunar surface, they tested the rangefinders again. Worryingly, there was some noise in the readings as the laser bounced off the Moon. However, the engineers had reason to believe that, maybe, the readings would improve as the spacecraft got nearer to the surface. https://arstechnica.com/space/2025/03/intuitive-machines-second-attempt-to-land-on-the-moon-also-went-sideways/ https://arstechnica.com/space/2025/03/intuitive-machines-sec... https://www.space.com/nasa-moon-landing-dust-concerns.html https://www.space.com/nasa-moon-landing-dust-concerns.html https://en.wikipedia.org/wiki/Lunar_horizon_glow https://en.wikipedia.org/wiki/Lunar_horizon_glow
      - ceejayoz 2y ago
        Noise at 30km altitude probably points more towards a sensor issue than dust.
        Aspos 2y ago
        May it be that laser bounced off exhaust plume?
        lightedman 2y ago
        I think it would be unlikely that a plume was caused from 30km away on something with no atmosphere.
        echoangle 2y ago
        Unless their processing is very weird, that shouldn’t be the issue. You send a pulse and record the output of a detector to listen for the reflection. If the laser is reflected at the plume, you should get some pulses very quickly, but also faint and spread out in time, which you would be able to tune out. And the real response from the ground should be more narrow because it’s reflecting at a single distance. If very short range noise influences the signal when measuring 30km real distance, you’re doing something wrong.
        inamberclad 2y ago
        Laser is angled outwards at approx 45 degrees, I think it's well away from the exhaust plume.
      - numpad0 2y ago
        LRFs and radars on the Moon has been fine for a long time, it can also be angled away from gravity axis and multiplied by sine theta if needed.
- 1970-01-01 2y ago
  If navigation was fine, why was touchdown on a plateau?
  - ceejayoz 2y ago
    Because "where am I" and "how high am I over that position" are very different things. Visual demonstration of being at the wrong altitude in the right spot: https://www.f-16.net/f-16-news-article968.html https://www.f-16.net/f-16-news-article968.html
    - deleted 2y ago
      [deleted]
    - echoangle 2y ago
      If you don’t know your altitude, navigation isn’t fine though. Navigation should give you a position in all axes.
- JshWright 2y ago
  The top-heavy design didn't help things either. I'll be shocked if they don't go three-for-three on landing sideways given IM3 has the same tall design.
  - ceejayoz 2y ago
    The company claims it's not as top-heavy as you'd think from pics: https://www.theregister.com/2025/03/07/intuitive_machines_landing/ https://www.theregister.com/2025/03/07/intuitive_machines_la... > At his press conference earlier today, Altemus defended the design, saying the spacecraft doesn’t have a high center of gravity because most of its cargo attaches to the base of the vehicle. He said there were no plans for a radical rethink of his company's design. (We see this in returning F9 first stages, as well.)
  - sandworm101 2y ago
    >> The top-heavy design didn't help things either Just wait for SpaceX to start trying to land starships on the moon. Also vertically. Also doomed to tip over whenever the surface is slightly out of spec. https://www.spacex.com/humanspaceflight/moon/ https://www.spacex.com/humanspaceflight/moon/
    - JumpCrisscross 2y ago
      > Just wait for SpaceX to start trying to land starships on the moon. Also vertically SpaceX has done it. To date, other nation-states have tried and failed to replicate their achievements in this domain. IM’s design is wrongly optimised and probably requires a rethink. That the CEO won’t contemplate this isn’t a great sign for the company.
      - CamperBob2 2y ago
        SpaceX has done it. SpaceX has landed Starship on the moon?!
        JumpCrisscross 2y ago
- nomel 2y ago
  > "Athena knew where it was relative to the surface of the Moon" - but without a working altimeter it was kinda fucked for actually touching down. Z is an axis that exists in our 3d world, and a required value for any relative position, which means it DID NOT know where it was, relative to the moon.
  - PantaloonFlames 2y ago
    Ya the wording was not quite … satisfactory. I think they meant , it could tell X and Y, but not Z. But all three are important. Related - I’m not clear how the article can describe that landing as “not crashing”. If that was not a crash, what was it? Will they call it a crash only if there are Hollywood-style explosions?
    - jacobgkau 2y ago
      Bringing "Hollywood-style explosions" into it is a little much. If you slam the breaks on in your car, your tires hit some debris in the road, and you spin around and end up somewhere you didn't intend to be, but the car wasn't meaningfully damaged (i.e. you didn't hit other cars or manmade structures), you made a dangerous uncontrolled maneuver, but you didn't crash. That seems more like how they're describing this "skid." Relevantly, it sounds like this lunar spacecraft was still functioning after the hard (non-)landing. The only reason it died after that was because of debris settling on the solar panels, which made it run out of power.
      - PhasmaFelis 2y ago
        If you do something with your car that ends up with it skidding on its side, that's a crash by any possible definition.
        jacobgkau 2y ago
        Probably, but this is a space probe, not a car. It's lighter than a car, and is operating in an environment with less gravity.
- meindnoch 2y ago
  But if they knew where it was relative to the surface of the Moon, they could have subtracted that from where it wasn't, or where it wasn't from where it was (whichever is greater), to obtain a difference, or deviation. The guidance subsystem could then use deviations to generate corrective commands to drive the missile from a position where it was to a position where it wasn't.
martin_drapeau 2y ago
Scott Manley has a great video explaining what he thinks happened. https://youtu.be/ISZTTEtHcTg?si=0LZFyiCysBiFZrMz https://youtu.be/ISZTTEtHcTg?si=0LZFyiCysBiFZrMz
- 1970-01-01 2y ago
  Scott Manley and I agree that altitude signal shouldn't matter if navigation is correct. Athena simply risked touchdown, and it didn't find a flat spot, it found a hole. https://youtu.be/ISZTTEtHcTg&t=1158 https://youtu.be/ISZTTEtHcTg&t=1158
  - ceejayoz 2y ago
    Can you quote the bit you think is relevant here? He's saying modern spacecraft can null out the horizontal velocity to land, but without an altimeter, you don't necessarily know when to do so, nor when to give the thrusters a little boost to avoid an obstacle you're about to hit, like a plateau.
- numpad0 2y ago
  tldw: speculation: landed with too much lateral velocity and one of legs broke
- someothherguyy 2y ago
  Does anyone know an extension that strips this tracking information and normalizes YouTube URLs?
  - tennox 2y ago
    There's tons... Firefox: https://addons.mozilla.org/en-US/firefox/addon/clearurls/ https://addons.mozilla.org/en-US/firefox/addon/clearurls/ Android: https://github.com/svenjacobs/leon https://github.com/svenjacobs/leon
  - wruza 2y ago
    Just in case, I’m using my own violentmonkey scripts rather than hoping for extensions, and everyone can do that too (now only on firefox, I guess, and maybe brave). For example, I remove &t=<n> from urls that youtube added recently in addition to regular watch position restoration. This broke it for me and they don’t seem to plan a revert.
russdill 2y ago
It touched down with a large horizontal velocity component
- PantaloonFlames 2y ago
  That’s another thing that bothered me about this story. They said they knew where the craft was , relative to the surface of the moon. Wouldn’t that also mean they should know of any substantial horizontal (x/y) component of velocity?
  - gtirloni 2y ago
    Yes, through image analysis.
  - marcosdumay 2y ago
    I don't know if it's the case, but there's a difference between knowing something and calculating its derivative fast enough for it to be useful.

bell-cot 2y ago

At what point do you just fire your entire "Land on Moon" software team, and hire a couple young Neil Armstrong wanna-be's, who can hand-land your spacecraft remotely? (In spite of the moon-earth-moon signal lag.)

ceejayoz 2y ago
You’d probably wanna make sure that’s the problem area first. Considering the altimeter failed, that seems unlikely to be the case.
PantaloonFlames 2y ago
In this domain, Signal lag seems to be an insurmountable problem, when using remote control. 2.7s delay will be hard to mitigate in a dynamic system. Unless I am misunderstanding something.
- nottorp 2y ago
  They could hire MMO players from areas with crap ping to the servers :)

dist-epoch 2y ago

Dumb question, but why can't it have a few simple telescopic sticks which extend to flip it over if it lands upside down. Seems it's the second time they fail in this mode.

ragebol 2y ago
Moe parts, more complexity, more weight.
hulitu 2y ago
Because: 1. It cannot fail in this mode. 2. Testing is done by the user, test results are sent by telemetry and the fix will be done, when the bug can be reproduced on developer's computers. /s
somenameforme 2y ago
Definitely not a dumb question. The first lander to land on the Moon (after many failures) is pretty amusing. [1] The Soviets a designed a lander that'd be launched right into the Moon but, just before impact would jettison the lander which itself was a highly reinforced ball that was then designed to simply pound into the Moon at 54kph, but survive the crash. The egg then unfurled and finally humanity had achieved a 'soft' landing on the Moon. Somehow it kind of makes one think of a really elaborate egg drop contest paired with a 'what happens if you jump right before the elevator crashes.' Like another comment mentioned, complexity and size are big issues. Some more are power/mechanics (fluids, such as for hydraulics, and -280F aren't gonna play well together) and then there's the fact that there's not even a guarantee it'd work. Your legs could get damaged, you might end up in an orientation where none of the legs are appropriate, and so on. So you may be adding a whole bunch of complexity for stuff that might not even save you in the situation it was designed for! [1] - https://en.wikipedia.org/wiki/Luna_9 https://en.wikipedia.org/wiki/Luna_9
notTooFarGone 2y ago
battlebots did it first!
mystified5016 2y ago
Mass. Each kilogram costs what, millions? Hundreds of millions? There's a small chance that navigation or landing fails in a way that would make those legs useful, and an even smaller chance that they'll save the mission. Given tight budgets, this is almost certainly not a gamble worth taking

areoform 2y ago

If you take the time to study the documentation from the 1950s & 1960s, the engineering culture of that era appears to be markedly different from the engineering culture prevalent today. And I think it's deeply rooted in the symbiotic relationship between computing, Baumol's cost disease and our obsession with precision, results-oriented, MBA-style-min-maxing, "good enough for government work" engineering. Robert Truax, the designer of the Sea Dragon, loved to promote the design paradigm of Big Dumb Boosters. Instead of many small, sophisticated rocket engines, what if we made one big robust one that can take a lickin' and keep on kickin'. The idea was to relax the mass margins and to create big. dumb. boosters. It's the approach TRW explicitly followed for the Lunar Module engine, > "There was an amusing but instructive side to this program. TRW farmed-out the fabrication of the engine and its supporting structure, less the injector that they fabricated themselves, to a "job-shop" commercial steel fabricator located near their facility . The contract price was $ 8000. Two TRW executives visited the facility to observe the fabrication process. They found only one individual working on the hardware, and when queried, he did not know nor care that he was building an aerospace rocket engine." > " I had arrived late to witness the test, and only saw the firing. I was told by others who witnessed the entire test procedure that the engine was pulled out of outdoor storage where it lay unprotected against the elements. Before it was placed on the launch stand, the test crew dusted off the desert sand that had clung to it. This unplanned inlcusion [sic] of a bit of an environmental test also demonstrated hardware ruggedness of the kind no other liquid rocket eingine [sic] could approach." The Surveyor program managed to make it "just work" 5 out of 7 times by adopting this approach. It had robust landing legs and RADAR. They would decelerate and then shut off the engine 11' above the surface. The wide, sturdy legs would then absorb that final impact of coming stand still from free fall. These programs had a lot of capital behind them. Some components required precision engineering, but there's a very clear through line and embrace of the "we gotta make stuff that can take a lickin' & keeps kickin'" philosophy. Modern engineering approaches seem to be the opposite of that. I think we've become so accustomed to living in a silicon driven world where our personal devices are engineered at microscopic level that we've forgotten how to do things the Apollo-era way. For example, to the best of my knowledge, IM-2 doesn't use RADAR — they're using LIDAR and optical navigation instead. Perhaps it is to save on mass and power so that more payload reaches the surface. Perhaps optical navigation was declared to be "good enough." Perhaps it doesn't make sense from a minmaxing of capital perspective. But this philosophy may not be suited to an untamed frontier. China adopted the Surveyor / Apollo-era philosophy. Their first successful lander, Chang'e 3, used the same hover & fall technique as Surveyor. > The vehicle will hover at this altitude, moving horizontally under its own guidance to avoid obstacles, and then slowly descend to 4 m above the ground, at which point its engine will shut down for a free-fall onto the lunar surface. The landing site will be at Sinus Iridum, at a latitude of 44º. It chose the terminal landing sites with the help of LIDAR and its cameras, but it relied on RADAR and a suite of sensors to have robust navigation. The follow up missions up-ed the ante every time, but they seem to have consistently focused on the robustness of their craft over precision, MBA-spreadsheet-oriented minmax-ing.

ck2 2y ago

Kinda explain why Neil Armstrong burned up all their fuel except for a few seconds scoping out the landing site in paranoia. Instead of building all these expensive to launch big landers, why not get some pizza-box sized probes into earth orbit AND THEN do like a slo-mo golf shot arcing to where the moon will be for a super slow/soft landing? Some will fail but if you launch 100 and get 20-30 working, there you go. As technology progresses, get it down to a shoe-box sized probe and then in 10 years smartphone sized (in 100 years tic-tac sized).

btbuildem 2y ago
Combine that with leaving the long-range comms (and higher-powered equipment) in lunar orbit as the "master" for all the probes scattered on the surface, and maybe the problem becomes simpler by breaking it in two.
mapt 2y ago
Space applications of all sorts are screaming out for mass production approaches. With so much design work and verification the actual manufacturing cost tends to be trivial by comparison, the work readily adapted to concurrent manufacturing processes.
- AStonesThrow 2y ago
  When I signed on to a Mars mission in 1999, the scientists told me that’s JPL’s approach: instead of extremely expensive, robust, redundant craft, they would begin to make leaner stuff and worry less when it failed... Around the same time, Mission Control was replacing their bespoke hardware with COTS and trying to minimize the “glue” HW/SW for space systems. You'll also see that expertise on a particular instrument package is leveraged over and over across multiple missions. NASA still has amazing educational outreach and makes incredible software, even for mere mortals.
accrual 2y ago
It's definitely possible to target a certain surface location on the moon from low Earth orbit and set off on a trajectory to get there with a single burn. However, as the craft(s) approach the moon and enter its sphere of influence, gravity will kick in and increase their relative velocity to the surface. Another burn (suicide burn if you're feeling lucky) would be needed for the soft touchdown. The moon is also gravitationally very "lumpy", so some small corrections might be needed along the way as well.

1970-01-01 2y ago

Here's the hole it fell into: https://www.lroc.asu.edu/images/1408 https://www.lroc.asu.edu/images/1408

CarRamrod 2y ago
There's a mote on the crack on the Mössbauer spectrometer on the instrument arm on the rover in the hole in the bottom of the sea of tranquility
freeopinion 2y ago
Great shoutout to Arizona State University for the images. I like to see when someone or some group gets some recognition for work they have performed in relative obscurity for a very long time. Years of craft, getting better and better at something most don't bother with. Then suddenly your expertise gets a spotlight in a meaningful way. (Yes, I suppose there are many other sources that could provide images. These happen to be from ASU.)

dang 2y ago

Related. Others? Athena spacecraft declared dead after toppling over on moon - https://news.ycombinator.com/item?id=43292471 https://news.ycombinator.com/item?id=43292471 - March 2025 (340 comments) The Moon Lander Athena's Fate on the Lunar Surface Is Uncertain - https://news.ycombinator.com/item?id=43283136 https://news.ycombinator.com/item?id=43283136 - March 2025 (1 comment)

Koshkin 2y ago

https://en.wikipedia.org/wiki/IM-2 https://en.wikipedia.org/wiki/IM-2

littlestymaar 2y ago

Can someone ELI5 why it's at that temperature? I mean, because it's in the dark I'd expect it to reach equilibrium with space background thermal radiation which is around 3K. Yet its 100K. Where does that heat comes from? It radiates from earth? Conduct through the floor coming from the inner of the moon itself? (Is there some kind of geothermal gradient on the moon BTW?)

antonvs 2y ago
There are multiple factors. The biggest ones are reflected sunlight; infrared and thermal conduction from surrounding rocks; and the Moon's internal heat (the region between the core and the mantle has a temperature of over 1,300 C).
- kQq9oHeAz6wLLS 2y ago
  Also, little atmosphere means the sun doesn't heat up the area like in your house. Once you're out of the sunlight, it's darn cold.
  - littlestymaar 2y ago
    The question isn't “why is it cold” but the opposite “why is it so hot” (100K when the universe radiation is 3K)

shadowgovt 2y ago

> As a result, the privately built spacecraft struck the lunar surface on a plateau, toppled over, and began to skid across the surface. As it did so, the lander rotated at least once or twice before coming to a stop in a small, shadowed crater. Oh yeah, we've all Kerbaled it in like that at one point or another.

dang 2y ago

[stub for offtopicness]

ThePowerOfFuet 2y ago
-173°C.
- oneshtein 2y ago
  100K
  - muzani 2y ago
    This actually puts it into perspective, knowing it's closer to absolute zero than room temperature.
    - layer8 2y ago
      It’s roughly a third of room temperature.
      - dietr1ch 2y ago
        Which is hard to grok since a third of something warm doesn't seem to be extremely cold.
        layer8 2y ago
        It’s sort-of the point to realize that it actually is (a third of something). The lander is receiving a third of the thermal energy that it would receive at room temperature. Warm-blooded mammals of course have a reference point based on their thermal homeostatic capabilities (ability to maintain body temperature). “Warm” and “cold” is in relation to that.
        ted_dunning 2y ago

accrual 2y ago

> For the second mission in a row, the lander's altimeter failed That's a bummer. Altimeters are relatively simple and defined hardware as far as I know. Send a ping, receive a ping, calculate. Too bad they didn't incorporate a backup solution.

aaron695 2y ago

[dead]

driggs 2y ago

Is there any sort of international body with regulatory power over the moon, or is it completely lawless and unrestricted? This startup has already crashed two pieces of space junk onto the lunar surface. Can any startup able to get there do whatever they want?

kQq9oHeAz6wLLS 2y ago
Well, there's a natural barrier to entry, i.e. it costs millions on dollars and years of time to be able to "crash" your "junk" onto the surface. So it's not like a bunch of hobby rocketeers are throwing away their McDonald's garbage. By the way, in comparison to the cost and complexity of said "junk", everything you own is cluttering up the Earth. You should really do something about that.
- driggs 2y ago
  Are you making the argument that anyone with enough money should be able to do whatever they want on the moon? Giant neon McDonalds billboards visible from everywhere on Earth? Mining with zero restriction on impacts to the surface of the Moon or its atmosphere? Apparently the HN crowd doesn't stand anyone criticizing a "startup", but I'm asking a legitimate question. So far most of the junk we've launched onto the Moon has been in the name of science and operated by nations. An assault by the Free Market is unprecedented. I'm asking a legitimate question about regulation, and implying a question about whether regulation is warranted.
  - kQq9oHeAz6wLLS 2y ago
    > Are you making the argument that anyone with enough money should be able to do whatever they want on the moon? No, I'm making the argument that anyone who invests the time and money into landing on the moon isn't doing it for giggles and the joy of littering. And let's be real, if we found "space junk" on the moon of an alien planet, we'd be thrilled as heck, so perhaps we're just seeding the moon with artifacts for alien races.
  - elzbardico 2y ago

ghostly_s 2y ago

This company's PR team is doing incredible work getting all this type of coverage out of a 0/2 track record with a design everyone else seems to think is obviously flawed.

Waterluvian 2y ago
What’s the prevailing criticism? High COG?
- JonChesterfield 2y ago
  It's tall and narrow and falls over when it hits the ground moving fast. Irritating for intuitive machines whose stance is that mass is not uniformly distributed and center of mass is already low enough to make flight control somewhat challenging. The criticism should perhaps be that the laser range finders are clearly a liability and a robust/workable backup for telling how far away the ground is needs to be brought along.
pdf2calguy 2y ago
hey man we made it on the rock and checked the weather thats cool right

yieldcrv 2y ago

> this mission was largely a success. What can he possibly mean by that? > Compared to the company's first spacecraft, Athena flew smoothly. Reminds me of the comedian opining on the flipped over airplane. “Did you know the pilot was a woman? [hecklers] Woah woah, I’m not saying women cant be pilots, thats not even accurate. She flew perfectly….. what I am saying is that she can’t drive”

deleted 2y ago

[deleted]

ivanjermakov 2y ago

Why people make temperature in space a big deal? It's mostly vacuum and has no heat capacity. Sun radiation is the real threat, but the concept of temperature can't even be applied to vacuum.

rtkwe 2y ago
The ground it's laying on though does though.
elzbardico 2y ago
The space surrounding you may not have a temperature but your spacecraft does, and it will lose heat via radiation, batteries and electronics will stop working after your temperature reaches a certain low.
- kortilla 2y ago
  Any moderately active satellite has far more issues with excess heat
  - snewman 2y ago
    The article clearly states that providing enough power to run the heaters was one of the challenges that led to the death of the probe. Satellites are rarely in the shade for an extended period.
  - verzali 2y ago
    It depends on the size of the satellite and its power use. Small spacecraft often don't use enough power to generate enough heat to warm themselves. The problem then is batteries get cold (which is one of the places you need heaters) and become inefficient and then you end up in death spiral. Here the probe likely wasn't generating enough power anyway, so that would almost certainly kill it before the cold.
    - dredmorbius 2y ago
      The problem is less the quantity of heat generated than of shedding that heat. Even modest electronics emit several watts of thermal waste heat, and given that the entire satellite is in a highly-insulating vacuum, as well as subject to solar insolation (at 1 kW/m²), it's easy to exceed thermal budgets.

behnamoh 2y ago

the second pic reminded me of the pale blue dot... it's a long way from home...

hilbert42 2y ago

This is horribly disappointing but I'm surprised the altimeter failed as I'd have thought this would have been one of the more reliable aspects of the mission. How does its altimeter work, exactly what tech does it use? It's worth remembering that radar-type altimeters have been around for a long time and are well developed. For example, Little Boy that was dropped on Hiroshima 80 years ago used radar altimeters in a redundancy arrangement (four devices) and that worked on first attempt. So what went wrong? Second question, was redundancy employed in the altimeter's design? Third, if the altimeter employed redundancy then why weren't its multiple sections of different designs to allow for the possibility that the reflected signal may be weak and noisy? (The strength of a returned wave from a radar transmission depends on various factors including its wavelength and the properties of the surface it's being reflected from. If there's any doubt the returned signal's S/N would be such that noise could be a problem it'd make sense for a redundant system to employ multiple wavelengths whose frequencies are far enough apart to take advantage of the fact that the moon's surface would reflect different wavelengths in different ways and at different signal strengths.)

virgildotcodes 2y ago

To be clear, I am in no way a conspiracy theorist, at all. Seriously, not just a bs disclaimer. That said, all of the recent photos of the moon that have come out in the last month or so look, to my eye, super CGI. Just uh, overly smooth and lacking in detail? Is there a reason for this or am I just tripping?

marcusverus 2y ago
There is no atmosphere, ergo no light diffusion. Shadows will be crisper, lit spots will be brighter, dark spots darker. It makes sense that such differences could make an image feel "off".
alex_young 2y ago
I’m not sure I get it. Can’t you just look at it yourself? It seems pretty real to me.
bbor 2y ago
What other pictures are you thinking of? I don’t recall any rovers since china’s (?) last year. These pictures in particular are taken from a very high altitude, which may explain why they look unnatural?

TimByte 2y ago

Space is one of those rare fields where partial success actually counts as genuine progress.

wesselbindt 2y ago
Exactly. I look forward to humanity genuinely progressing towards successfully landing stuff on the moon. One day, we may even be able to land humans there! Intuitive systems is really pushing the envelope here, and I think that's worthy of admiration.

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lionkor 2y ago

the altimeter? Surely you would put three on there?

mattlondon 2y ago
+1 They had the altimeter fail on the previous mission too. Seems like a fairly crucial component of a moon lander. Armchair rocket scientist here, but if I were on that engineering team I'd lobby hard for less science payloads and more backups for critical instruments for the actual flight of the craft. The rover and hopper and drill etc all sound cool yes, but worthless if you can't land. Again. For the second time. Because the same critical component failed, again. With apparently no backup, again. Of course, it sounds so simple. I am sure there is more to it (e.g. perhaps they had backups and everything worked, but they just weren't fit for purpose?)
- T-A 2y ago
  > They had the altimeter fail on the previous mission too. Not really. They forgot to toggle the safety switch on before launch, so the laser could not be used: https://spaceq.ca/simple-error-could-have-resulted-in-intuitive-machines-mission-failure/ https://spaceq.ca/simple-error-could-have-resulted-in-intuit...
JonChesterfield 2y ago
Had two. One showed so much measurement noise they couldn't trust it, other kept cutting out. Not great.
- lionkor 2y ago
  So three ones, two different models, one in a different location. These are like... basics, no?
  - ricardobeat 2y ago
    If you multiply every critical component by 3x there will be no room left for anything else.

jiggawatts 2y ago

Scott Manley put together a great analysis of why it tipped over: https://youtu.be/ISZTTEtHcTg https://youtu.be/ISZTTEtHcTg TL;DW: It had far too much sideways velocity immediately before touchdown, likely due to some guidance-system failure. It would have crashed even if it was crab-shaped instead of tower-shaped.

jmmcd 2y ago

> The Athena spacecraft was not exactly flying blind as it approached the lunar surface one week ago. The software on board did a credible job of recognizing nearby craters, even with elongated shadows over the terrain. However, the lander's altimeter had failed. > So while Athena knew where it was relative to the surface of the Moon, the lander did not know how far it was above the surface. This is really crappy writing. That second paragraph sounds like a self-contradiction. Unless "the lander" is a separate entity from "Athena"? Some publications refuse to use the same term twice, even if it introduces ambiguity as here.

EGG_CREAM 2y ago
In their defense, using Athena again here would have definitely sounded strange and not natural. But, they could have used the word “it” without introducing ambiguity, which they do 2 times already.
randallsquared 2y ago
It knew where it was selenographically, which is what the author means by "relative to the surface of the moon", I think.
kryogen1c 2y ago
> That second paragraph sounds like a self-contradiction Aside from the point you made, it actually IS a contradiction. Paraphrased: >> Athena knew where it was relative to the surface of the Moon, but Athena did not know how far it was above the surface of the moon. Relative position includes height/altitude? One understands from context, but this sentence does not carry meaning itself.
- HenryBemis 2y ago
  I read this and I thought it was a bad writing, and I assumed (right or wrong) that (metaphor ensues): The airplane's pilot could see where the ground was and he estimated it was 1000m-1200m below. But the instrument of the airplane were malfunctioning and reported that the ground was at 500m (or 5000m). This caused the plane to override/resist the pilot's manual landing efforts causing the plane to ultimately crash but not allowing the wheels to come down and the flaps to do turn. So two different mechanisms, providing contradicting evidence, and the lack of a 'higher' deciding authority to use 'judgment' and/or other inputs to 'decide' which reported measurements are more accurate, and thus make the viable decision/take the viable action. I get that for such devices every-gram-counts, and perhaps from now on some devices/mechanisms that are truly single-points-of-failure, will get 2x or 3x for redundancy/contingencies. If your ABC-camera fails, it's 'ok' you can still get images from your DEF and GHI will give you some data, reducing to 80% the output of the mission, but still not making it 5%. Your 'landing equipment' fails, and you get out only 5% of the value (flying/trajectory/telemetry of flight/perhaps some eclipse photos).

Aerroon 2y ago

Is there any reason why we couldn't have some rudimentary GPS-like satellites around the moon? That could help out these kinds of landers, no?

freeopinion 2y ago
Who do you propose should fund lunar GPS for the benefit of private companies who want to land on the moon?
- krisoft 2y ago
  The private companies. But “who should fund this?” is a separate question from “would this help?”. I don’t think it would really help that much, and that is the reason why the private companies are not doing it.
tliltocatl 2y ago
High lunar orbits is unstable because of Earth influence (i. e. long-term orbiting requires lots of fuel for extensive orbit maintenance). Most low orbits are unstable as well because of uneven mass distribution, but there are some exceptions: https://en.wikipedia.org/wiki/Frozen_orbit https://en.wikipedia.org/wiki/Frozen_orbit Low orbits would also require either more satellites for complete coverage or synchronizing launch window, which is PITA enough as it is now.
- scoofy 2y ago
  But would they need to be in the orbit? Since nothing is on the moon, couldn't you just create a GPS array on the ground?
  - addaon 2y ago
    For a GNSS-type system to work, you need four transmitters in sight. This would imply a moderately dense ground network on the moon for a receiver at orbital height -- and as this article points out, we're not doing great at building even a spare ground network of right-side-up transmitters right now -- but would need increasing density for a descending receiver. We don't really have challenges right now with accurately determining orbital parameters of probes above the moon, it's the final few miles where GNSS-level accuracy would be tempting; but that's also the domain where seeing four ground-based transmitters is basically impossible.

inamberclad 2y ago

Welp, I worked on this one. Specifically, I worked on the laser rangefinders which are under so much scrutiny. I no longer work at Intuitive Machines, but I'm certainly interested in finding out what happened to the lasers this time.

yieldcrv 2y ago
some of the comments here are suggesting the lander chose that spot, as opposed to crashing and skidding across the surface before settling in the spot purely due to inertia, what's the merit to that?
- inamberclad 2y ago
  I did not work on the HDA algorithm which is responsible for landing site deviation, but this technology was inherited from NASA's Project Morpheus, which could intelligently detect hazards and divert to safer sites.
krisoft 2y ago
Ooo. Not sure if you can tell us anything. If you can’t I totally understand. But in case you can: Was a radar based altimeter considered? How do you guys deal with kicked up regolith? (I have seen first hand how hard heavy snow is on lidars, and would imagine that regolith “shower” is similar, but what do I know.)
- inamberclad 2y ago
  The lasers are smaller and lighter than most radar systems. They're also pointed out at about 45 degrees from the lander and they're not supposed to be used for the last few dozen meters of descent.
  - krisoft 2y ago
    Thank you!

throway456aef 2y ago

[dead]

villmann 2y ago

How can you have temperature without a medium? The lander would have steadily lost temperature through heat radiation, but it's not like the vacuum had a temperature in the crater.