Athena landed in a dark crater where the temperature was -280° F / -173° C
276 comments
·March 14, 20251970-01-01
freeopinion
Great shoutout to Arizona State University for the images. I like to see when someone or some group gets some recognition for work they have performed in relative obscurity for a very long time. Years of craft, getting better and better at something most don't bother with. Then suddenly your expertise gets a spotlight in a meaningful way.
(Yes, I suppose there are many other sources that could provide images. These happen to be from ASU.)
CarRamrod
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
dang
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)
inamberclad
Welp, I worked on this one. Specifically, I worked on the laser rangefinders which are under so much scrutiny. I no longer work at Intuitive Machines, but I'm certainly interested in finding out what happened to the lasers this time.
krisoft
Ooo. Not sure if you can tell us anything. If you can’t I totally understand.
But in case you can: Was a radar based altimeter considered?
How do you guys deal with kicked up regolith? (I have seen first hand how hard heavy snow is on lidars, and would imagine that regolith “shower” is similar, but what do I know.)
inamberclad
The lasers are smaller and lighter than most radar systems. They're also pointed out at about 45 degrees from the lander and they're not supposed to be used for the last few dozen meters of descent.
krisoft
Thank you!
yieldcrv
some of the comments here are suggesting the lander chose that spot, as opposed to crashing and skidding across the surface before settling in the spot purely due to inertia, what's the merit to that?
inamberclad
I did not work on the HDA algorithm which is responsible for landing site deviation, but this technology was inherited from NASA's Project Morpheus, which could intelligently detect hazards and divert to safer sites.
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.
someothherguyy
Does anyone know an extension that strips this tracking information and normalizes YouTube URLs?
tennox
There's tons... Firefox: https://addons.mozilla.org/en-US/firefox/addon/clearurls/ Android: https://github.com/svenjacobs/leon
wruza
Just in case, I’m using my own violentmonkey scripts rather than hoping for extensions, and everyone can do that too (now only on firefox, I guess, and maybe brave).
For example, I remove &t=<n> from urls that youtube added recently in addition to regular watch position restoration. This broke it for me and they don’t seem to plan a revert.
numpad0
tldw: speculation: landed with too much lateral velocity and one of legs broke
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?
meindnoch
But if they knew where it was relative to the surface of the Moon, they could have subtracted that from where it wasn't, or where it wasn't from where it was (whichever is greater), to obtain a difference, or deviation. The guidance subsystem could then use deviations to generate corrective commands to drive the missile from a position where it was to a position where it wasn't.
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.)
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.
tekla
Why do people keep thinking this thing is top heavy just because its taller than wide?
The heavy bits are at the bottom.
_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.
walrus01
Was there no functioning laser or radar altimeter for the final descent phase?
ceejayoz
"However, the lander's altimeter had failed."
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
russdill
It touched down with a large horizontal velocity component
PantaloonFlames
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
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
Yes, through image analysis.
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.
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.
nine_k
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
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.
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.
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.
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.
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.
echoangle
> 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.
nexuist
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.
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.
Alex-Programs
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.
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.
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.
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!
moffkalast
Just give the RCS thrusters enough power to lift it sideways. Works every time in KSP.
ragebol
Moe parts, more complexity, more weight.
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?
lionkor
the altimeter? Surely you would put three on there?
mattlondon
+1
They had the altimeter fail on the previous mission too. Seems like a fairly crucial component of a moon lander.
Armchair rocket scientist here, but if I were on that engineering team I'd lobby hard for less science payloads and more backups for critical instruments for the actual flight of the craft.
The rover and hopper and drill etc all sound cool yes, but worthless if you can't land. Again. For the second time. Because the same critical component failed, again. With apparently no backup, again.
Of course, it sounds so simple. I am sure there is more to it (e.g. perhaps they had backups and everything worked, but they just weren't fit for purpose?)
T-A
> They had the altimeter fail on the previous mission too.
Not really. They forgot to toggle the safety switch on before launch, so the laser could not be used:
https://spaceq.ca/simple-error-could-have-resulted-in-intuit...
JonChesterfield
Had two. One showed so much measurement noise they couldn't trust it, other kept cutting out. Not great.
lionkor
So three ones, two different models, one in a different location. These are like... basics, no?
ricardobeat
If you multiply every critical component by 3x there will be no room left for anything else.
bilekas
If I’m not mistaken there are three on commercial aircraft.. Seems like the bare minimum for a lunar lander .. I can’t imagine they’re THAT heavy
florbo
Heavier than you think, probably. I tried looking up laser altimeters suitable for moon landings and was met with a much higher than anticipated amount of complexity. One thing was clear: the higher the altimeter needs to work, the heavier.
adastra22
Every gram of weight is directly trading off payload.
Aerroon
Is there any reason why we couldn't have some rudimentary GPS-like satellites around the moon? That could help out these kinds of landers, no?
tliltocatl
High lunar orbits is unstable because of Earth influence (i. e. long-term orbiting requires lots of fuel for extensive orbit maintenance). Most low orbits are unstable as well because of uneven mass distribution, but there are some exceptions: https://en.wikipedia.org/wiki/Frozen_orbit Low orbits would also require either more satellites for complete coverage or synchronizing launch window, which is PITA enough as it is now.
scoofy
But would they need to be in the orbit? Since nothing is on the moon, couldn't you just create a GPS array on the ground?
addaon
For a GNSS-type system to work, you need four transmitters in sight. This would imply a moderately dense ground network on the moon for a receiver at orbital height -- and as this article points out, we're not doing great at building even a spare ground network of right-side-up transmitters right now -- but would need increasing density for a descending receiver. We don't really have challenges right now with accurately determining orbital parameters of probes above the moon, it's the final few miles where GNSS-level accuracy would be tempting; but that's also the domain where seeing four ground-based transmitters is basically impossible.
tliltocatl
>nothing is on the moon
It's not exactly nothing, the moon itself with its mountains is there and blocking the radio signal and it means propagation isn't unlike that of VHF/UHF on Earth. You still only have no visibility beyond the horizon. In order for it to be visible and useful during landing you would need the base station to be reasonably close. I guess that would make it more akin to ILS/VOR/DME than GPS. That obviously wouldn't be feasible until we have a permanent base there (perhaps an unmanned one).
freeopinion
Who do you propose should fund lunar GPS for the benefit of private companies who want to land on the moon?
krisoft
The private companies.
But “who should fund this?” is a separate question from “would this help?”.
I don’t think it would really help that much, and that is the reason why the private companies are not doing it.
h3half
Not really, yes (though possibly not for the actual landing, depending on accuracy), and it's actively being worked on: https://www.intuitivemachines.com/post/nasa-awards-intuitive...
IM didn't win the contact because of their landers per se, but obviously as a company they have a vested interest in this kind of lunar infrastructure. Being able to build it with a bunch of public money is a huge win for them
ghostly_s
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
What’s the prevailing criticism? High COG?
JonChesterfield
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
hey man we made it on the rock and checked the weather thats cool right
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.
PantaloonFlames
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
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
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.
TimByte
The challenge, though, isn't just landing softly - it's surviving afterward
jiggawatts
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.
Here's the hole it fell into:
https://www.lroc.asu.edu/images/1408