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

https://arstechnica.com/space/2025/03/athena-landed-in-a-dark-crater-where-the-temperature-was-minus-280-f/

by 01-_- • 1 year ago

231 267 1 year ago

bell-cot• 1 year 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.)

ceejayoz8• 1 year ago

You’d probably wanna make sure that’s the problem area first.

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

PantaloonFlames4• 1 year 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• 1 year ago

They could hire MMO players from areas with crap ping to the servers :)

dist-epoch• 1 year ago

Dumb question, but why can't it have a few simple telescopic sticks which extend to flip it over if it lands upside down.

Seems it's the second time they fail in this mode.

ragebol• 1 year ago

Moe parts, more complexity, more weight.

hulitu• 1 year 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.

somenameforme4• 1 year 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

notTooFarGone• 1 year ago

battlebots did it first!

mystified5016• 1 year 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

ceejayoz8• 1 year ago

NASA paid $65M for the launch. It's about 2,000 kilos.

$32k/kilo or so.

tapotatonumber92• 1 year ago

How about a parachute to keep it the right way up?

appleorchard462• 1 year ago

Not enough of an atmosphere.

moffkalast• 1 year ago

Just give the RCS thrusters enough power to lift it sideways. Works every time in KSP.

1970-01-016• 1 year ago

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

ceejayoz8• 1 year 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.

1970-01-016• 1 year ago

If navigation was fine, why was touchdown on a plateau?

walrus01• 1 year ago

Was there no functioning laser or radar altimeter for the final descent phase?

JshWright• 1 year 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.

nomel3• 1 year 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.

meindnoch• 1 year ago

But if they knew where it was relative to the surface of the Moon, they could have subtracted that from where it wasn't, or where it wasn't from where it was (whichever is greater), to obtain a difference, or deviation. The guidance subsystem could then use deviations to generate corrective commands to drive the missile from a position where it was to a position where it wasn't.

martin_drapeau• 1 year ago

Scott Manley has a great video explaining what he thinks happened. https://youtu.be/ISZTTEtHcTg?si=0LZFyiCysBiFZrMz

1970-01-016• 1 year 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

numpad02• 1 year ago

tldw: speculation: landed with too much lateral velocity and one of legs broke

someothherguyy• 1 year ago

Does anyone know an extension that strips this tracking information and normalizes YouTube URLs?

russdill• 1 year ago

It touched down with a large horizontal velocity component

PantaloonFlames4• 1 year 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?

areoform2• 1 year 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.

dylan6043• 1 year 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• 1 year 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.

cratermoon3• 1 year 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.

j_bum• 1 year 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

somenameforme4• 1 year ago

What an absolutely phenomenal speech and video. Just a sort of +1 highly recommended thing. That video was crazy insightful.

antonvs2• 1 year 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.

somenameforme4• 1 year 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• 1 year 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• 1 year 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

areoform2• 1 year 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.

Macha• 1 year 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.

1970-01-016• 1 year 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.

dmurray• 1 year 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.

echoangle3• 1 year 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.

nexuist• 1 year 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.

throwaind29k• 1 year 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.

IX-103• 1 year ago

If they can fit 10x the payload for 1/100 the price, then maybe it's okay if some of them fail? Quantity has a quality of it's own.

ck2• 1 year ago

Kinda explain why Neil Armstrong burned up all their fuel except for a few seconds scoping out the landing site in paranoia.

Instead of building all these expensive to launch big landers, why not get some pizza-box sized probes into earth orbit AND THEN do like a slo-mo golf shot arcing to where the moon will be for a super slow/soft landing?

Some will fail but if you launch 100 and get 20-30 working, there you go.

As technology progresses, get it down to a shoe-box sized probe and then in 10 years smartphone sized (in 100 years tic-tac sized).

btbuildem• 1 year ago

Combine that with leaving the long-range comms (and higher-powered equipment) in lunar orbit as the "master" for all the probes scattered on the surface, and maybe the problem becomes simpler by breaking it in two.

mapt• 1 year 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• 1 year 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.

accrual2• 1 year 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.

PantaloonFlames4• 1 year 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)

TimByte3• 1 year ago

The challenge, though, isn't just landing softly - it's surviving afterward

1970-01-016• 1 year ago

Here's the hole it fell into:

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

CarRamrod• 1 year 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

freeopinion2• 1 year ago

Great shoutout to Arizona State University for the images. I like to see when someone or some group gets some recognition for work they have performed in relative obscurity for a very long time. Years of craft, getting better and better at something most don't bother with. Then suddenly your expertise gets a spotlight in a meaningful way.

(Yes, I suppose there are many other sources that could provide images. These happen to be from ASU.)

dang4• 1 year 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)

Koshkin2• 1 year ago

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

littlestymaar2• 1 year 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?)

antonvs2• 1 year 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).

kQq9oHeAz6wLLS3• 1 year 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.

shadowgovt2• 1 year 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.

dang4• 1 year ago

[stub for offtopicness]

ThePowerOfFuet• 1 year ago

-173°C.

oneshtein• 1 year ago

100K

elviejo• 1 year ago

I know I'm a snob... but I can't read science news using the imperial system.

ggm• 1 year 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.

jdminhbg• 1 year 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.

nntwozz• 1 year 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

shmerl• 1 year 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.

ninalanyon• 1 year ago

But it only looks like Imperial, it's almost certainly actually US Customary.

kiicia2• 1 year ago

No sane person can

Koshkin2• 1 year ago

   -280F = -173.33333C
   +280F = +137.77777C

chairmansteve• 1 year ago

Wow. Cosmic resonance man...

scotty79• 1 year 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.

jdlyga• 1 year ago

Minus 173° C. The US does use Fahrenheit, but not for science.

Symbiote• 1 year 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.

dang4• 1 year 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.

smolder• 1 year 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• 1 year ago

The articles (except for the syndicated Wired articles) are great, but the comment section is Reddit-level degeneracy.

accrual2• 1 year 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.

driggs3• 1 year 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?

kQq9oHeAz6wLLS3• 1 year 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.

driggs3• 1 year 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.

ghostly_s• 1 year 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• 1 year ago

What’s the prevailing criticism? High COG?

JonChesterfield2• 1 year 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• 1 year ago

hey man we made it on the rock and checked the weather thats cool right

yieldcrv2• 1 year 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”

ivanjermakov2• 1 year 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.

rtkwe2• 1 year ago

The ground it's laying on though does though.

elzbardico3• 1 year ago

The space surrounding you may not have a temperature but your spacecraft does, and it will lose heat via radiation, batteries and electronics will stop working after your temperature reaches a certain low.

kortilla• 1 year ago

Any moderately active satellite has far more issues with excess heat

NL807• 1 year 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.

dredmorbius2• 1 year ago

And: if one designed ones spacecraft / lander with a presumption of being exposed to solar radiation, which peaks around 120°C (250°F), then the temperature-management problem is one of excess heat, not insufficient heat, and would feature radiators and foil insulation to avoid acquiring more heat.

Designing for a wide range of temperatures in space where shedding heat is a challenge and running heaters (during dark/cold periods) is necessary, and where at the best of times re-deploying radiators and heat shields is difficult, let alone when the craft is lying on its side.

So ambient temperature matters. As another comment notes, in most cases, the problem is excess heat and the shedding of it. Particularly for Earth-orbiting satellites, which are subject to 1kW/m² solar radiation and are in shadow for only a small portion of their orbit (less with higher altitudes).

Dylan16807• 1 year ago

It's small enough to lose plenty of heat without conduction.

humanfromearth9• 1 year ago

Because it's lethal

TimByte3• 1 year 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.

ivanjermakov2• 1 year ago

Does it matter, if vacuum does not conduct heat? Lander would not experience conductive heat unless it has a great contact with the ground.

behnamoh• 1 year ago

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

hilbert42• 1 year ago

This is horribly disappointing but I'm surprised the altimeter failed as I'd have thought this would have been one of the more reliable aspects of the mission.

How does its altimeter work, exactly what tech does it use? It's worth remembering that radar-type altimeters have been around for a long time and are well developed. For example, Little Boy that was dropped on Hiroshima 80 years ago used radar altimeters in a redundancy arrangement (four devices) and that worked on first attempt.

So what went wrong? Second question, was redundancy employed in the altimeter's design? Third, if the altimeter employed redundancy then why weren't its multiple sections of different designs to allow for the possibility that the reflected signal may be weak and noisy?

(The strength of a returned wave from a radar transmission depends on various factors including its wavelength and the properties of the surface it's being reflected from. If there's any doubt the returned signal's S/N would be such that noise could be a problem it'd make sense for a redundant system to employ multiple wavelengths whose frequencies are far enough apart to take advantage of the fact that the moon's surface would reflect different wavelengths in different ways and at different signal strengths.)

virgildotcodes• 1 year ago

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

Is there a reason for this or am I just tripping?

marcusverus• 1 year ago

There is no atmosphere, ergo no light diffusion. Shadows will be crisper, lit spots will be brighter, dark spots darker. It makes sense that such differences could make an image feel "off".

alex_young• 1 year ago

I’m not sure I get it. Can’t you just look at it yourself? It seems pretty real to me.

bbor• 1 year 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?

TimByte3• 1 year ago

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

wesselbindt• 1 year ago

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

lionkor3• 1 year ago

the altimeter? Surely you would put three on there?

mattlondon• 1 year ago

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• 1 year ago

They had the altimeter fail on the previous mission too.

Not really. They forgot to toggle the safety switch on before launch, so the laser could not be used:

https://spaceq.ca/simple-error-could-have-resulted-in-intuit...

JonChesterfield2• 1 year ago

Had two. One showed so much measurement noise they couldn't trust it, other kept cutting out. Not great.

lionkor3• 1 year ago

So three ones, two different models, one in a different location. These are like... basics, no?

bilekas• 1 year ago

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• 1 year ago

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.

adastra225• 1 year ago

Every gram of weight is directly trading off payload.

jiggawatts• 1 year 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.

jmmcd• 1 year ago

The Athena spacecraft was not exactly flying blind as it approached the lunar surface one week ago. The software on board did a credible job of recognizing nearby craters, even with elongated shadows over the terrain. However, the lander's altimeter had failed.
So while Athena knew where it was relative to the surface of the Moon, the lander did not know how far it was above the surface.

This is really crappy writing. That second paragraph sounds like a self-contradiction. Unless "the lander" is a separate entity from "Athena"? Some publications refuse to use the same term twice, even if it introduces ambiguity as here.

EGG_CREAM• 1 year 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.

kryogen1c• 1 year ago

That second paragraph sounds like a self-contradiction

Aside from the point you made, it actually IS a contradiction. Paraphrased:

> Athena knew where it was relative to the surface of the Moon, but Athena did not know how far it was above the surface of the moon.

Relative position includes height/altitude? One understands from context, but this sentence does not carry meaning itself.

HenryBemis• 1 year ago

I read this and I thought it was a bad writing, and I assumed (right or wrong) that (metaphor ensues):

The airplane's pilot could see where the ground was and he estimated it was 1000m-1200m below. But the instrument of the airplane were malfunctioning and reported that the ground was at 500m (or 5000m). This caused the plane to override/resist the pilot's manual landing efforts causing the plane to ultimately crash but not allowing the wheels to come down and the flaps to do turn.

So two different mechanisms, providing contradicting evidence, and the lack of a 'higher' deciding authority to use 'judgment' and/or other inputs to 'decide' which reported measurements are more accurate, and thus make the viable decision/take the viable action.

I get that for such devices every-gram-counts, and perhaps from now on some devices/mechanisms that are truly single-points-of-failure, will get 2x or 3x for redundancy/contingencies. If your ABC-camera fails, it's 'ok' you can still get images from your DEF and GHI will give you some data, reducing to 80% the output of the mission, but still not making it 5%. Your 'landing equipment' fails, and you get out only 5% of the value (flying/trajectory/telemetry of flight/perhaps some eclipse photos).

randallsquared• 1 year ago

It knew where it was selenographically, which is what the author means by "relative to the surface of the moon", I think.

Aerroon• 1 year ago

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

freeopinion2• 1 year ago

Who do you propose should fund lunar GPS for the benefit of private companies who want to land on the moon?

krisoft3• 1 year ago

The private companies.

But “who should fund this?” is a separate question from “would this help?”.

I don’t think it would really help that much, and that is the reason why the private companies are not doing it.

tliltocatl3• 1 year ago

High lunar orbits is unstable because of Earth influence (i. e. long-term orbiting requires lots of fuel for extensive orbit maintenance). Most low orbits are unstable as well because of uneven mass distribution, but there are some exceptions: https://en.wikipedia.org/wiki/Frozen_orbit Low orbits would also require either more satellites for complete coverage or synchronizing launch window, which is PITA enough as it is now.

scoofy3• 1 year ago

But would they need to be in the orbit? Since nothing is on the moon, couldn't you just create a GPS array on the ground?

h3half• 1 year ago

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

inamberclad4• 1 year ago

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

yieldcrv2• 1 year ago

some of the comments here are suggesting the lander chose that spot, as opposed to crashing and skidding across the surface before settling in the spot purely due to inertia, what's the merit to that?

inamberclad4• 1 year ago

I did not work on the HDA algorithm which is responsible for landing site deviation, but this technology was inherited from NASA's Project Morpheus, which could intelligently detect hazards and divert to safer sites.

krisoft3• 1 year ago

Ooo. Not sure if you can tell us anything. If you can’t I totally understand.

But in case you can: Was a radar based altimeter considered?

How do you guys deal with kicked up regolith? (I have seen first hand how hard heavy snow is on lidars, and would imagine that regolith “shower” is similar, but what do I know.)

inamberclad4• 1 year ago

The lasers are smaller and lighter than most radar systems. They're also pointed out at about 45 degrees from the lander and they're not supposed to be used for the last few dozen meters of descent.

villmann• 1 year ago

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

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

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