Athena landed in a dark crater where the temperature was minus 280° F
123 comments
·March 14, 2025dang
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)
1970-01-01
Still unclear what happened. Did they not anticipate a big moon hole or did navigation fail when the rangefinder failed?
martin_drapeau
Scott Manley has a great video explaining what he thinks happened. https://youtu.be/ISZTTEtHcTg?si=0LZFyiCysBiFZrMz
1970-01-01
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.
ceejayoz
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.
ceejayoz
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
> "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
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?
1970-01-01
If navigation was fine, why was touchdown on a plateau?
ceejayoz
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
JshWright
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
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_
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.
tekla
Why do people keep thinking this thing is top heavy just because its taller than wide?
The heavy bits are at the bottom.
sandworm101
>> 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.
russdill
It touched down with a large horizontal velocity component
areoform
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."
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.
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
> "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.
jjmarr
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/...
areoform
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
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
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.
appleorchard46
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
> 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
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
The constrained optimization part is good, though.
Macha
> 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
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.
antonvs
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
What an absolutely phenomenal speech and video. Just a sort of +1 highly recommended thing. That video was crazy insightful.
dylan604
> 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
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
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
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.
dmurray
> 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.
1970-01-01
>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.
shadowgovt
> 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.
dist-epoch
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
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!
ragebol
Moe parts, more complexity, more weight.
moffkalast
Just give the RCS thrusters enough power to lift it sideways. Works every time in KSP.
mystified5016
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
NASA paid $65M for the launch. It's about 2,000 kilos.
$32k/kilo or so.
notTooFarGone
battlebots did it first!
hulitu
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
How about a parachute to keep it the right way up?
appleorchard46
Not enough of an atmosphere.
ck2
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
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.
mapt
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
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
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.
bell-cot
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
You’d probably wanna make sure that’s the problem area first.
Considering the altimeter failed, that seems unlikely to be the case.
littlestymaar
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
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).
aaron695
[dead]
dang
[stub for offtopicness]
Koshkin
-280F = -173.33333C
+280F = +137.77777Cscotty79
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
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
trhway
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
Anyone who has done cryotherapy?
null
chairmansteve
Wow. Cosmic resonance man...
jdlyga
Minus 173° C. The US does use Fahrenheit, but not for science.
elviejo
I know I'm a snob... but I can't read science news using the imperial system.
ggm
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.
rufname
I made this, but have not tested it yet with this website:
nntwozz
Everyone knows feet and British stones is the way to measure things in space. Just ask any scientician:
samstave
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.
nextts
Ahhhh...
ninalanyon
But it only looks like Imperial, it's almost certainly actually US Customary.
kiicia
No sane person can
jdminhbg
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
-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.
shmerl
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.
ThePowerOfFuet
-173°C.
Here's the hole it fell into:
https://www.lroc.asu.edu/images/1408