Still unclear what happened. Did they not anticipate a big moon hole or did navigation fail when the rangefinder failed?
Scott Manley has a great video explaining what he thinks happened.
https://youtu.be/ISZTTEtHcTg?si=0LZFyiCysBiFZrMz
Athena landed in a dark crater where the temperature was -280° F / -173° C
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Re: Athena landed in a dark crater where the temperature was -280° F / -173° C
#42Earlier quoted context omitted.
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.
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.
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.)
Re: Athena landed in a dark crater where the temperature was -280° F / -173° C
#43Dumb 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.
How about a parachute to keep it the right way up?
Re: Athena landed in a dark crater where the temperature was -280° F / -173° C
#44If 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 Tru…
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
What an absolutely phenomenal speech and video. Just a sort of +1 highly recommended thing. That video was crazy insightful.
Re: Athena landed in a dark crater where the temperature was -280° F / -173° C
#45Earlier quoted context omitted.
Was there no functioning laser or radar altimeter for the final descent phase?
"However, the lander's altimeter had failed."
Looking at this closely, it was working, however it was noisy. I speculate that they didn't correctly anticipate the moon dust problem. Laser rangefinders may not be a workable solution for future landings.
So engineers at Intuitive Machines had checked, and re-checked, the laser-based altimeters on Athena. When the lander got down within about 30 km of the lunar surface, they tested the rangefinders again. Worryingly, there was some noise in the readings as the laser bounced off the Moon. However, the engineers had reason to believe that, maybe, the readings would improve as the spacecraft got nearer to the surface.
Re: Athena landed in a dark crater where the temperature was -280° F / -173° C
#46Earlier quoted context omitted.
"However, the lander's altimeter had failed."
Looking at this closely, it was working, however it was noisy. I speculate that they didn't correctly anticipate the moon dust problem. Laser rangefinders may not be a workable solution for future landings. So engineers at Intuitive Machines had checked, and re-checked, the laser-based altimeters on Athena. When the lander got down within about 30 km of the lunar surface, they tested the rangefinders again. Worryingl…
Noise at 30km altitude probably points more towards a sensor issue than dust.
Re: Athena landed in a dark crater where the temperature was -280° F / -173° C
#47Earlier quoted context omitted.
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 eng…
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 tra…
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.
Re: Athena landed in a dark crater where the temperature was -280° F / -173° C
#48Earlier quoted context omitted.
If navigation was fine, why was touchdown on a plateau?
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
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Re: Athena landed in a dark crater where the temperature was -280° F / -173° C
#49Still unclear what happened. Did they not anticipate a big moon hole or did navigation fail when the rangefinder failed?
Scott Manley has a great video explaining what he thinks happened. https://youtu.be/ISZTTEtHcTg?si=0LZFyiCysBiFZrMz
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.
Re: Athena landed in a dark crater where the temperature was -280° F / -173° C
#50Earlier quoted context omitted.
Scott Manley has a great video explaining what he thinks happened. https://youtu.be/ISZTTEtHcTg?si=0LZFyiCysBiFZrMz
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
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.