27 comments

  • jmmcd 1 hour 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.

    • kryogen1c 37 minutes 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.

    • EGG_CREAM 1 hour 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.
  • smolder 5 hours ago
    Ars has been one of the best publications across my whole experience with the internet, going on 20+ years. Without them I wouldn't have been clued into how broken the internet is.
    • scarab92 3 hours ago
      The articles (except for the syndicated Wired articles) are great, but the comment section is Reddit-level degeneracy.
      • pclmulqdq 9 minutes ago
        The articles often have good style, but redditor-level insight.
  • 1970-01-01 19 hours ago
    Here's the hole it fell into:

    https://www.lroc.asu.edu/images/1408

    • CarRamrod 2 hours 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
  • ivanjermakov 10 hours 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.
    • elzbardico 9 hours 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.
      • NL807 5 hours ago
        >The space surrounding you may not have a temperature

        Just to be pedantic, it actually does, which is the microwave background radiation. But that doesn't detract anything from your point.

        • winwang 3 hours ago
          Is that really "space" as opposed to "the lingering effects of the big bang"? (or less interestingly, the temperature of the CMB photon gas)
          • danwills 2 hours ago
            I don't think a photon can exist outside of space, but I'd be very interested to hear of any alternate points of view on that!
      • kortilla 5 hours ago
        Any moderately active satellite has far more issues with excess heat
        • verzali 3 hours 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.
        • snewman 5 hours 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.
    • rtkwe 10 hours ago
      The ground it's laying on though does though.
    • TimByte 5 hours ago
      The problem here isn't the vacuum itself, but that surfaces facing away from the sun radiate heat rapidly into space, causing extremely low temperatures on lander components. That's why temperature still matters practically, even if it's a bit counterintuitive.
    • Dylan16807 8 hours ago
      It's small enough to lose plenty of heat without conduction.
    • humanfromearth9 5 hours ago
      Because it's lethal
  • dang 16 hours ago
    Related. Others?

    Athena spacecraft declared dead after toppling over on moon - 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 - March 2025 (1 comment)

  • lionkor 4 hours ago
    the altimeter? Surely you would put three on there?
    • JonChesterfield 1 hour ago
      Had two. One showed so much measurement noise they couldn't trust it, other kept cutting out. Not great.
    • mattlondon 2 hours 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?)

  • 1970-01-01 21 hours ago
    Still unclear what happened. Did they not anticipate a big moon hole or did navigation fail when the rangefinder failed?
    • martin_drapeau 19 hours ago
      Scott Manley has a great video explaining what he thinks happened. https://youtu.be/ISZTTEtHcTg?si=0LZFyiCysBiFZrMz
      • someothherguyy 6 hours ago
        Does anyone know an extension that strips this tracking information and normalizes YouTube URLs?
      • 1970-01-01 19 hours 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

        • ceejayoz 19 hours 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 7 hours ago
        tldw: speculation: landed with too much lateral velocity and one of legs broke
    • ceejayoz 21 hours 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.

      • nomel 13 hours 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 12 hours 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 11 hours 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 11 hours 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.
            • Retric 6 hours ago
              One of the legs broke off which requires significant forces not just a skid.

              I mean if my car lands on the side and one of it’s wheels fell off that’s a significant crash.

            • rdiddly 10 hours ago
              "The only reason?" One reason for prematurely losing most of the investment is enough. The car analogy is inadequate but let's say my car skids gently into a position from which it won't start and I can't get out and I slowly die of starvation and/or hypothermia. Am I glad that I didn't "crash?"
      • 1970-01-01 20 hours ago
        If navigation was fine, why was touchdown on a plateau?
        • ceejayoz 19 hours 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

          • echoangle 10 hours ago
            If you don’t know your altitude, navigation isn’t fine though. Navigation should give you a position in all axes.
      • JshWright 19 hours 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 19 hours 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_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.)

        • _bin_ 15 hours ago
          i think this becomes somewhat less of an issue once SpaceX gets Starship fulfilling contracts at scale. they're limited in width by the max payload faring width for Falcon 9, which is like half that of starship. add to that an exec claimed it's tall but not necessarily top-heavy as mass isn't evenly distributed throughout.
          • strangattractor 12 hours ago
            Or use New Glenn which works now and has a larger faring.
        • sandworm101 15 hours 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/

          • oceanplexian 9 hours ago
            Why does this even have to be a problem?

            We can send small probes to image the moon in incredibly high resolution. It's a big place I'm sure there is a perfectly flat rock somewhere they can use.

          • JumpCrisscross 15 hours 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 15 hours ago
              SpaceX has done it.

              SpaceX has landed Starship on the moon?!

              • JumpCrisscross 15 hours ago
                SpaceX has repeatedly and reliably landed vertical stacks. On any body. Out of the engineering problems inherent to HLS, sticking the landing isn’t material because for them, for that team, it isn't as novel a problem as e.g. in-orbit refuelling or getting Raptors to relight on the Moon.

                Put another way, just because SpaceX has done it doesn't mean the same problem carries the same risk for a team like IM's.

                • MegaButts 14 hours ago
                  Has SpaceX ever landed their rocket on a surface that isn't purposefully engineered to be flat?
                  • Seanambers 14 hours ago
                    Multiple sea landings, but I guess you'd argue those don't count since the vehicles tip over in water and explode.

                    Moving barges in the sea should qualify though.

                    • hildolfr 13 hours ago
                      A moving barge with a known flat surface of a known hardness and stability is a whole different category of difficult than doing the same thing on naturally occurring terrain with unknown voids, hardness, roughness and consistency.
                    • ohgr 10 hours ago
                      So what you're saying is we need to blast some barges into space and land them on the moon so we have a flat surface for starship to land on?
                    • PhasmaFelis 11 hours ago
                      Is a landing barge not "purposefully engineered to be flat"?
                    • TylerE 10 hours ago
                      They also have the atmosphere, with drag that will make all velocities trend towards zero. Don’t have that on the moon, gotta do it all with fuel. More than half of the energy she’s by the returning falcon is aerobraking.

                      Yes, the moon has substantially less gravity but it’s also exponentially harder to get the fuel there.

            • sandworm101 15 hours ago
              Lol. SpaceX has landed on prepared surfaces, concrete pads on land or on large barges. They literally have a big X to mark the target. Let's see them land on some random beach, an uneven surface that may or may not subside. But that is still peanuts comparted to the moon's surface.
              • nomel 12 hours ago
                For any of these landings, it's a problem of 3d positional/velocity precision. SpaceX has prove that they can reliably land on a target, usually within meters, with negligibly delta velocity on contact.

                In other words, they've proven they have the control systems in place for placing a craft at a precise location, with a precise velocity. What requirement do you see outside of this that are far outside of placement and velocity? Autonomous mapping and adjustments for approach maybe?

                Let's not assume they're going to try to use their current earthly landing legs.

                > land on some random beach,

                They did this I believe two starships ago, when they landed in the ocean. Came to zero xyz velocity some target distance above the water, and hovered for a bit. Unfortunately, the surface tension of the sea couldn't support the weight once they lowered for touchdown.

              • JumpCrisscross 14 hours ago
                > that is still peanuts comparted to the moon's surface

                Sure. I'm not trivialising the problem in an absolute sense. Just going from floating barge or chopsticks to Moon is a simpler set of problems than reïnventing the sort of translational velocity and attitude control needed to get to first base.

                • ted_dunning 13 hours ago
                  You say this based on your history of landing rockets on the moon?

                  And on your history of dealing with the lunar regolith near the poles?

                • sandworm101 14 hours ago
                  For selecting and touching down on an unprepared surface, rockets are not the stepping stone. Start with helicopters. It is the same problem: can I land there and what will happen when I put weight on the surface. Try programing a large helicopter to identify and land on a random chunk of rocky terrain. It is not easy. And the bigger/taller the craft, the more difficult it becomes. Then add a 10-second time limit.
                  • Kye 13 hours ago
                    Are the sky cranes of Mars viable without an atmosphere?
            • Frederation 12 hours ago
              Keep that Musk copium going, man!
        • tekla 15 hours ago
          Why do people keep thinking this thing is top heavy just because its taller than wide?

          The heavy bits are at the bottom.

          • timmg 15 hours ago
            > Why do people keep thinking this thing is top heavy just because its taller than wide?

            Because it keeps falling over?

            • tekla 15 hours ago
              The landing leg broke. How does that show you its top heavy?
              • timmg 13 hours ago
                I didn't say it was top-heavy. I answered the question, "Why does everyone think it is top heavy?"
                • tekla 13 hours ago
                  Ah complete total ignorance. Figures
      • walrus01 20 hours ago
        Was there no functioning laser or radar altimeter for the final descent phase?
        • ceejayoz 19 hours ago
          "However, the lander's altimeter had failed."
          • 1970-01-01 19 hours 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-sec...

            https://www.space.com/nasa-moon-landing-dust-concerns.html

            https://en.wikipedia.org/wiki/Lunar_horizon_glow

            • ceejayoz 19 hours ago
              Noise at 30km altitude probably points more towards a sensor issue than dust.
              • Aspos 14 hours ago
                May it be that laser bounced off exhaust plume?
                • echoangle 10 hours 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.

            • numpad0 6 hours 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.
    • russdill 14 hours ago
      It touched down with a large horizontal velocity component
      • PantaloonFlames 12 hours 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?
        • marcosdumay 5 hours 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.
        • gtirloni 9 hours ago
          Yes, through image analysis.
  • areoform 21 hours 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.

    • somenameforme 20 hours ago
      > "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."

      This is a really interesting point. I think a practical issue in modern times as well is that companies are being inspired by SpaceX while forgetting that it took SpaceX alot of work to get to the point of being able to do things like casually land a 20 story tower in the middle of the ocean on a barge, let alone the even more ridiculous 'stunts' they're doing with Starship.

      Apollo was starting from the perspective of trying to do something where it was even debatable about whether it was possible. And so I think there was a lot more 'humility' in design, for lack of a better word.

      • nine_k 11 hours ago
        As they say, when in doubt, take a bigger hammer. Not a sophisticated high-precision low-tolerance tool. That tool works well (better than the hammer) when you already have no doubts, when you precisely understand how things are going to work.
    • jjmarr 20 hours ago
      You're criticizing the prioritization of cost, not the concept of trying to solve for constraints. Engineering is about constrained optimization to meet customer needs.[1] Learning this is a core part of the curriculum at my accredited engineering school.

      > Engineering design is a process of making informed decisions to creatively devise products, systems, components, or processes to meet specified goals based on engineering analysis and judgement. The process is often characterized as complex, open-ended, iterative, and multidisciplinary. Solutions incorporate natural sciences, mathematics, and engineering science, using systematic and current best practices to satisfy defined objectives within identified requirements, criteria and constraints.

      > Constraints to be considered may include (but are not limited to): health and safety, sustainability, environmental, ethical, security, economic, aesthetics and human factors, feasibility and compliance with regulatory aspects, along with universal design issues such as societal, cultural and diversification facets.

      It's not an MBA philosophy but is intrinsic to the profession. Apollo didn't go up because of vibes, it went up because engineers knew the goals going in and to figured out how much fuel was needed to go to the moon. It also went up because the United States was willing to spend over a quarter of a trillion dollars (adjusted for inflation) on getting there,[2] and ignored the arguments that it was a giant waste of money while there were social problems at home.[3]

      [1]https://egad.engineering.queensu.ca/wp-content/uploads/2023/...

      [2] https://www.planetary.org/space-policy/cost-of-apollo

      [3] https://en.wikipedia.org/wiki/Whitey_on_the_Moon

      • areoform 20 hours ago
        This comment isn't directed at you jjmarr, I appreciate your take, but I think it's important to point out that,

            > constrained optimization to meet customer needs
        
        
        is MBA-capture in action.

        For most of its existence as a formal field, engineering wasn't about making geegaws that "meet customer needs." It was about building stuff that matters. Houses that didn't collapse. Roads and machines that made it possible to traverse vast distances. Toys that delighted us. Aquaducts that delivered clean water. Drainage that helped remove muck. Plumbing that cleaned our cities. Threshers that helped us harvest crops. Lights that vanquished the dark.

        The story of engineering is the story of creating technology that helps alleviate want.

        You can say that there was a "customer" for each, which is great and all, but that's not why we did it. We did it so that we could move out of the caves and not be in filth and muck all the time.

        We did it because it felt good. And we did it because it was the right thing to do.

        • tremon 19 hours ago
          I don't understand what you are objecting to. Is it just the phrasing that's bothering you? Because from my point of view, "houses that don't collapse" and "machines that can travel vast distances" are all formulations of customer needs. And dealing with contraints is pretty much engineering 101, every project is at the very least constrained on two of these axes: cost, construction time or material availability.
          • rout39574 14 hours ago
            Not GP, but I think the objection is: the engineer wants to build a thing cheaply enough that it functions, and then cheaply as can be while maintaining function.

            The MBA wants to build a thing as cheaply as can be while extracting maximum value from the process. Maintaining function is only relevant inasmuch as is necessary for marketing. Enshittification is offensive to the engineer, and is a deliberate calculated tactic for the MBA.

            We're replete with case studies, but my favorite is Kitchen-Aid mixers which accumulated a reputation when they were the small version of Hobart mixers, and have in succeeding decades become a cheap pile of crap because the optimization does not care about quality of function so long as the appearance of quality can be maintained. And it's cheaper to look quality than it is to be so.

            A close second is Singer in the '70s, which for a while decided to ship items with 100-hour motors because "Folks don't usually spend much time _actually_ sewing". Contrast with the machines built a centuryish before. We've got an early electric model which is still doing fantastic precise work. The engineer would enthuse over the superb work that went into building such a tool, and the MBA would focus on the foregone sales, the value not extracted.

        • appleorchard46 17 hours ago
          I was watching this documentary Happy People, about people who live in the Siberian Taiga (by Werner Herzog, would highly recommend). A man is talking about making a new set of skis, and it shows the incredibly long and careful process of selecting the perfect trees, chopping them down in the right way, treating the wood and so on. He mentions how mass manufactured skis are light and cheap and will work fine for a while, but when one breaks and you're in the Siberian wilderness you can't just go to the store for a replacement. That really stuck with me.

          1960s US is hardly Siberia and I don't think any NASA engineers had their heads on the chopping block if their designs failed. But engineering philosophy was still rooted in survival; the primary goal was to make something that wouldn't kill you because it fails.

          You hear stories about artisans in the old days refusing work because they don't believe what they're being asked to make is safe or reliable enough for the person asking for it. Maybe it's romanticized and idealized, maybe it's just them covering their ass so they don't get blamed. But that philosophy of personal responsibility not just for making things according to the constraints, but for the outcome too, is something that served society well for a long time before slowly disappearing over the past century or so.

          It hasn't left without reason. As the things being made became less key to survival and more key to thrival, as the world became more interconnected and safe, it didn't make as much sense. Just think of how many crazy, inventive concepts we use every day wouldn't have been made if they could only be made to work reliably! Our entire modern existence is based off things that don't work reliably. It's a blessing and a curse.

          But when we're exploring the final frontier we need frontier thinking and frontier technology; things that, from the ground up, are built to work first with all other constraints secondary. Unfortunately spaceflight endeavors today must invariably build off the 'good enough, when it breaks just make a new one' foundation that permeates modern design at every level. Even if you want to make something nowadays with the sole purpose of working, as long as you're using any technological advancements made in the past 50 years chances are you're using something that wasn't made with that goal in mind.

        • FredPret 15 hours ago
          > stuff that matters

          Matters to whom?

          Answer: that's the definition of a customer in an engineering project

          Matters how / why?

          Answer: those are the requirements / user stories.

          Helping people by doing engineering feels good and is the right thing to do, but formalizing this process a bit does not detract from it.

        • s1artibartfast 19 hours ago
          I think you are presenting a romanticized fictional narrative, especially when it comes to aerospace.

          When engineers were working on Apollo and lunar landers, they were working on a set of customer requirements a mile long. Roving tinkerers didn't build the moon rockets. Engineers spent countless hours in design reviews with the customer, in this case, NASA.

          Roman engineers didn't build aqueducts and colosseums on a lark, or some sense of poetic destiny.

        • cratermoon 20 hours ago
          The constrained optimization part is good, though.
    • Macha 20 hours 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.

      I wonder how much of that is because of public attitudes to government spend. Like if a SpaceX rocket blows up, they're taking innovative, risk-taking approaches to rocket development. If a NASA rocket blows up they're wasting tax payer funding.

      Similarly the pressure on NASA to have fewer programs for cost saving is similar. If NASA has two rocket programs, one of which is at a "good enough" level for launching satellites economically into space and one of them is a "safety conscious" rocket for manned launches at a higher per-mission cost, then people look at this and think why is NASA duplicating work and spending. So now they get only one program, so then even launching a GPS satellite is the expensive, human-safe rocket.

    • j_bum 20 hours ago
      This reads like a “comment” version of Destin’s speech to a NASA group a few years ago [0]. The loss of institutional knowledge and fundamentals philosophical differences seem like they’ll need to be overcome.

      [0] https://youtu.be/OoJsPvmFixU?si=EUxpp6C9vRAYD3kA

      • antonvs 15 hours ago
        The talk was to the American Astronautical Society, not specifically a NASA group. But Destin talked as though he imagined everyone in the audience worked at NASA. It actually bothered me a bit - if I had been at that talk I would have been a bit pissed off, because he was basically using it as a channel to talk to people who probably weren't actually even there.

        Just youtubers doing youtube things, I guess.

      • somenameforme 19 hours ago
        What an absolutely phenomenal speech and video. Just a sort of +1 highly recommended thing. That video was crazy insightful.
        • Alex-Programs 9 hours ago
          Was it? I read it as a pretty hyped up version of "old space guy says to old space people that they're not old spacing enough, presents it as rebellion". In particular (and, to be clear, it's been a while) he kept going "why not do it like apollo" when the entire point is that it isn't Apollo anymore.

          Though, again, it's been a while since I watched it.

          • somenameforme 2 hours ago
            He wasn't just saying 'do it like Apollo did' in terms of tech, but rather focusing on the process. I think the key takeaway is that one of the main things they did during Apollo was to obsessively try to get everybody to express their honest feedback, and especially negative feedback. Artemis isn't ever going anywhere for a million reasons, of which he listed a couple of random ones, but everybody keeps pretending it is.

            That's because the powers that be surround themselves with yes-men or (equivalently) people are afraid of the consequences for stating their honest opinion, when that opinion is negative. It's a problem as old as time. "The Emperor's New Clothes" is based on tales dating back to around 1000AD, and I'm sure it goes back far further than that. This problem destroys competence, destroys countries, and has become ubiquitous in every single aspect of high level public (and to a lesser degree even high level private) decision making in the US.

            Notice how things seem to constantly just go wrong in spite of effectively endless resources and manpower? If you look at what we have today in terms of any quantifiable metric we should be able to run circles around the 60s (in terms of, amongst other things, tech advancement) with our eyes shut, yet in practice we're struggling to recreate what they did in the 60s, in 7 years, starting from nothing and on a [relatively] extremely limited budget.

    • dylan604 20 hours ago
      > Perhaps it is to save on mass and power so that more payload reaches the surface.

      It doesn't matter how much mass was saved and how much more payload that allowed to reach the surface if the landing isn't successful. Successful landing is mandatory for anything else to matter. The obviousness of this baffles me that it is taken so haphazardly.

      • ordu 20 hours ago
        I believe that the thing you are missing is Intuitive Machines aims at landing a lot of spacecrafts, not just one. They hope to have a limited number of failures to land which will teach them how to do it reliably. We might doubt will this work or not, but if we accept the plan then it becomes a rational decision to increase the engineering complexity and risks of failure by saving on mass, because in the long run less missions will allow to land more payload.

        Though, of course, I wonder how many landings they are planning to do, and how many of them they need to do to compensate for each failure to land.

        • dylan604 20 hours ago
          Again, if you can't stick the landing, you might as well not have any payload on it. So if you're worried about cost, keep testing until you can stick the landing with dummy mass. Once that works, send the real payload. Otherwise, you're just wasting payload.

          The mindset difference seems to be that if there's no human on board, so no problemo wasting a lander if something goes wrong. That's just a bad attitude (as well as yaw and roll). If you designed everything with "baby on board" hanging in the window, you'd probably not cut so many corners so sharply. Otherwise, why not just light your cigars with hundred dollar bills. How would you feel if you were on the team building the payload, but the lander guys keep fucking up so you just wasted however much time you spent because "meh, we're just testing". In sports, there's a saying "practice like you play because you play like you practice".

          • cratermoon 20 hours ago
            Okay but successfully landing an inanimate carbon rod is easy, but why?
            • dylan604 19 hours ago
              Who said it was easy? I'm saying they are not giving it enough respect because of the attitude of "it's only a test". That's bad. It's still expensive to get to that point. They have become complacent/lazy with the luxury of being able to iterate. Rather than spending money on engineering testing, they just build "real things" that don't work and improve the failed things. Never mind that if procedure 10 failed, you never get to test procedure 11+. So your next launch fails at procedure 11. It's just a bad attitude.
      • cratermoon 20 hours ago
        To a point. Landing a solid brick of aluminum isn't much good, unless the entire goal of the exercise is to get a successful landing of something.
    • nexuist 11 hours ago
      It is all downstream of the loss of the manufacturing industry in America. In the 50s you could entrust a random guy to build a liquid rocket engine in a dusty garage because he spent every day of his career building various pipes and combustion chambers. All of these guys are now dead or retired so when you try to build hardware today you get new grads who settle on LIDAR and computer vision not because it is the best choice but because it is literally all that they are familiar with; the old solutions have all ceased to exist within the minds of employees and classrooms.
    • dmurray 15 hours ago
      > China adopted the Surveyor / Apollo-era philosophy. Their first successful lander, Chang'e 3, used the same hover & fall technique as Surveyor.

      Dropping the last 4 metres isn't a sign of having a ruggedized, over-speced "takes a lickin' and keeps on kicking' approach". In lunar gravity, you could drop a raw egg from that height and not perturb the chick inside.

      Instead the aim is to avoid throwing up too much moon dust with retro rockets.

      Luna 9 (1966) really did need to withstand a bit of a bump, but it was 22km/h, comparable with a fast running pace or a car in first gear, not a high speed impact.

      • echoangle 10 hours ago
        > Dropping the last 4 metres isn't a sign of having a ruggedized, over-speced "takes a lickin' and keeps on kicking' approach". In lunar gravity, you could drop a raw egg from that height and not perturb the chick inside.

        Just for maximum pedantry:

        Falling 4 m on the moon is like falling 66 cm or about 2 feet on earth. I don’t know about your eggs but the ones I know wouldn’t survive that.

    • 1970-01-01 19 hours ago
      >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.

      I think this is the smoking gun. RADAR is usually successful, while LIDAR has a poor record.

    • throwaind29k 9 hours ago
      If you look at Change 5 and 6, they seem to do the same image processing based landing control. This doesn't seem to be a cost cutting measure, since the image processing is computationally much more complex than using a radar altimeter.
  • ghostly_s 11 hours 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 10 hours ago
      What’s the prevailing criticism? High COG?
      • JonChesterfield 10 minutes 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 10 hours ago
      hey man we made it on the rock and checked the weather thats cool right
  • TimByte 5 hours ago
    Space is one of those rare fields where partial success actually counts as genuine progress.
  • driggs 12 hours 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 11 hours 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 11 hours 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.

        • elzbardico 9 hours ago
          Are you making the argument that for some reason we should heavily discourage lunar exploration for the sake of keeping the moon pristine?

          Why is this more important than expanding our ability as a species to explore space?

          • driggs 8 hours ago
            Regulation doesn't mean "heavily discourage".

            Keeping the Moon, or Mars, or Venus as pristine as possible is the only way we can study those environments as they exist in their natural condition. Not to mention that we can't detect the presence of life on those worlds if we've contaminated them with life from our own.

            If you think this idea is incompatible with exploration, you can take it up with NASA's Office of Planetary Protection:

            https://sma.nasa.gov/sma-disciplines/planetary-protection

        • kQq9oHeAz6wLLS 10 hours 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.

  • dist-epoch 21 hours 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.

    • somenameforme 21 hours 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

    • ragebol 21 hours ago
      Moe parts, more complexity, more weight.
    • moffkalast 14 hours ago
      Just give the RCS thrusters enough power to lift it sideways. Works every time in KSP.
    • notTooFarGone 20 hours ago
      battlebots did it first!
    • mystified5016 20 hours 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

      • ceejayoz 19 hours ago
        NASA paid $65M for the launch. It's about 2,000 kilos.

        $32k/kilo or so.

    • hulitu 21 hours 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

    • tapotatonumber9 19 hours ago
      How about a parachute to keep it the right way up?
  • jiggawatts 2 hours ago
    Scott Manley put together a great analysis of why it tipped over: 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.

  • hilbert42 9 hours 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.)

  • shadowgovt 15 hours 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.

  • Koshkin 15 hours ago
  • ck2 20 hours 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).

    • accrual 20 hours 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.

      • PantaloonFlames 12 hours ago
        First time encountering the phrase “gravitationally lumpy”. I can imagine what that is. But why? I suppose it would naturally occur if the moon were not more or less consistent density. But how would that be possible given the moon’s age and shape. (Roughly spherical I am assuming)
        • eichin 4 hours ago
          Buried "mascons" (mass concentrations), https://en.wikipedia.org/wiki/Gravitation_of_the_Moon has some nice color maps of the deviations/anomalies. (TLDR: some of it is explained by basalt but not all of it, and it's still being studied, because it interferes with low altitude lunar orbits.)
    • mapt 20 hours 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 17 hours 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.

    • btbuildem 20 hours 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.
    • TimByte 5 hours ago
      The challenge, though, isn't just landing softly - it's surviving afterward
  • bell-cot 1 day 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.)
    • PantaloonFlames 12 hours 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 2 hours ago
        They could hire MMO players from areas with crap ping to the servers :)
    • ceejayoz 13 hours ago
      You’d probably wanna make sure that’s the problem area first.

      Considering the altimeter failed, that seems unlikely to be the case.

  • behnamoh 9 hours ago
    the second pic reminded me of the pale blue dot... it's a long way from home...
  • littlestymaar 15 hours 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 14 hours 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 11 hours 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 9 hours ago
          The question isn't “why is it cold” but the opposite “why is it so hot” (100K when the universe radiation is 3K)
  • yieldcrv 11 hours 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”

  • dang 13 hours ago
    [stub for offtopicness]
    • Symbiote 12 hours ago
      That seems rather uncharitable. I looked through the comments as soon as I saw there wasn't a Celsius figure in the headline or first paragraph.

      One conversion comment is on-topic, even though any replies to it are most likely to be off-topic.

      • dang 11 hours ago
        I hear you, but it's a classic generic tangent—in fact a classic generic flamewar tangent. HN commenters are asked to resist those - see https://news.ycombinator.com/newsguidelines.html - even though it borders on irresistible.

        Edit: but I've put the Celsius number in the title now as well...hopefully that will reduce the swelling.

        • netsharc 4 hours ago
          I noticed it didn't have the Celsius value at the beginning, and a while later I noticed it was there. But "minus 280 F / 173 C" is terrible formatting, it looks like it's positive in Celsius...

          Considering the conversion between the 2 temperature scales can flip the sign (e.g. -10C is 14F), "-280F/-173C" would've been a lot clearer.

    • Koshkin 15 hours ago

         -280F = -173.33333C
         +280F = +137.77777C
      • scotty79 15 hours ago
        I refuse to believe anyone knows how cold -280F is.

        When you have such extreme temperatures you think in Kelvin or at least Celsius.

        • usrnm 14 hours ago
          It's not like using Kelvin or Celsius helps you grasp these temperatures. -173C is very, very cold, but how cold? What can you compare it to? Not many humans have any experience with something of this scale
          • alwayslikethis 14 hours ago
            Liquid nitrogen (boiling at -196 C) is a semi-common substance that people would have heard of, though not everyone would have seen or interacted with it.
            • inetknght 13 hours ago
              I've seen liquid nitrogen, briefly, as it was sprayed out of a hose. It immediately boiled into a (quite cold) gas, of course. I was told not to play with it too much because they would have to evacuate the building. Oh the joys of "bring your kid to work" days in manufacturing facilities
            • mncharity 13 hours ago
              That's the example Copilot used when asked to make a list of temperatures in 50 C steps with an example or two of something around that temperature that people might have heard of. Also cryogenic freezing of biological samples.
          • NikolaNovak 13 hours ago
            Fair, but in Celsius or Kelvin I know how close it is to absolute zero. In Fahrenheit I have no idea!
            • wnoise 13 hours ago
              Got it, I should use Rankine.
          • Vilian 14 hours ago
            You compare to 0 kelvin, you know where it's on the Celsius scale, not on F
            • mordechai9000 14 hours ago
              Maybe the Rankine temperature could be provided, as well.
          • kiicia 13 hours ago
            -173C is just twice your typical winter in Yakutia
        • trhway 14 hours ago
          Or you can think that way - you at 36 C radiate 900 W away while from our usual environment you get 800+ W radiated (and also transferred by air) at you (with your body producing that 50-100W difference), and at 280F you’d get only mere watts radiated at you from the environment while you still would start radiating at 900 and going quickly downhill from that as you surface quickly cools down (that is supposing you don’t have some performance enhancing stuff Expanse style to generate 900 watts boiling you blood to bring those 900 watts non stop to the skin) until coming into equilibrium with the environment.
        • nextts 14 hours ago
          Anyone who has done cryotherapy?
      • chairmansteve 15 hours ago
        Wow. Cosmic resonance man...
    • elviejo 19 hours ago
      I know I'm a snob... but I can't read science news using the imperial system.
      • ggm 15 hours ago
        You would think either they could parameterise all units or a plausible browser extension could convert elephants to swimmingpools and King's thumbs to badly measured fractions of a diameter.
      • nntwozz 15 hours ago
        Everyone knows feet and British stones is the way to measure things in space. Just ask any scientician:

        https://m.youtube.com/watch?v=nRnt3TE-V-Y

        • samstave 13 hours ago
          Speaking of "feet" as a measurement - Randall Carlson has an AMAZING video[0] on the source of the 12 inch foot.

          And how its all related to the measurement of the precession of the earth. And yes - its specifically how to measure things in space. And its all from Sacred Geometry.

          [0] https://www.youtube.com/watch?v=R7oyZGW99os

        • nextts 14 hours ago
          Ahhhh...
      • jdminhbg 15 hours ago
        Well, the definition of 0ºC is based on the freezing point of water at one atmosphere of pressure, which isn't super relevant on the Moon. You could give it in K but that's not very relatable.
        • 0cf8612b2e1e 15 hours ago
          -280F, -173C, or 100K is not relatable to anyone except niche researchers. Maybe slap in the extra few people who happen to work with liquid helium and you are still talking about 0% of the population.
      • ninalanyon 14 hours ago
        But it only looks like Imperial, it's almost certainly actually US Customary.
      • kiicia 13 hours ago
        No sane person can
      • shmerl 14 hours ago
        I agree, especially scientific articles should just stick to metric, period.

        At least inside the article both units are actually used, just the title is imperial only.

    • jdlyga 13 hours ago
      Minus 173° C. The US does use Fahrenheit, but not for science.
    • ThePowerOfFuet 21 hours ago
      -173°C.
      • oneshtein 20 hours ago
        100K
        • muzani 20 hours ago
          This actually puts it into perspective, knowing it's closer to absolute zero than room temperature.
          • layer8 19 hours ago
            It’s roughly a third of room temperature.
            • dietr1ch 15 hours ago
              Which is hard to grok since a third of something warm doesn't seem to be extremely cold.
              • abdullahkhalids 13 hours ago
                This is an interesting explanatory challenge.

                Temperature is roughly how fast molecules are moving, vibrating etc. And the impact of low/higher temperature are really how fast molecules are knocking you. For an ideal gas, temperature is proportional to the square of the velocity.

                So at room temperature (300K), the speed of the molecules is roughly 300^0.5 = 17.3 in some arbitrary units. If you drop down to freezing point of water, (273K), speed is 16.5. And that is starting to get cold. -40C (as cold as most humans will experience) is 15.3. So each drop of 1 in speed is pretty drastic.

                At 100K, the speed is 10, or 7 drops from 17. That should be a lot colder than room temperature. But not cold enough. Most of the speed is still there, we haven't even cut it by half. It's the next few 1/3rd cuts of the temperature that will start to get us closer to zero speed.

                • dietr1ch 12 hours ago
                  It's hard, I can imagine the average kinetic energy slowing down, but can't imagine heat halving since there's no halving we can feel without dying.

                  Humans should experience something within -50°C to 50°C for most, if not their entire lives, but that's just 223K to 323K, maybe that's the range we can understand as a warmth difference, so getting to that temperature might feel like that super wide, in human warmth terms, drop in temperature twice, which still feels unimaginably cold.

              • layer8 14 hours 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 13 hours ago
                  I don't think that black-body radiative transfer is a linear process.

                  The Stefan-Boltzman relation says power scales with the fourth power of temperature. So 1/3 absolute temperature would be 1/81 the inbound radiative energy. If you are getting 800W inbound at room temp, you would get 10W inbound at 100K (=300K/3).

            • tempodox 15 hours ago
              Exactly, the Kelvin unit makes it easy to see that. I can't believe they used fucking Fahrenheit in the title.
              • shadowgovt 15 hours ago
                "You know how hot you feel when you're running a fever? Well, it was nearly three times that cold!"
  • aaron695 12 hours ago
    [dead]
  • virgildotcodes 8 hours 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?

    • alex_young 8 hours ago
      I’m not sure I get it. Can’t you just look at it yourself? It seems pretty real to me.
    • marcusverus 8 hours 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".
    • bbor 8 hours 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?

  • accrual 13 hours 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.