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

arstechnica.com

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

#31

Post by cratermoon »

dylan604 wrote: post #23
ordu wrote: post #19

Earlier quoted context omitted.

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 le…

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 we…

Okay but successfully landing an inanimate carbon rod is easy, but why?

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

#32

Post by ceejayoz »

walrus01 wrote: post #27
ceejayoz wrote: post #8

Earlier 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.

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

"However, the lander's altimeter had failed."

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

#33

Post by ceejayoz »

1970-01-01 wrote: post #25
ceejayoz wrote: post #8

Earlier 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.

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

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

#35

Post by dylan604 »

cratermoon wrote: post #31
dylan604 wrote: post #23

Earlier quoted context omitted.

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 we…

Okay but successfully landing an inanimate carbon rod is easy, but why?

Who said it was easy? I'm saying they are not giving it enough respect because of the attitude of "it's only a test". That's bad. It's still expensive to get to that point. They have become complacent/lazy with the luxury of being able to iterate. Rather than spending money on engineering testing, they just build "real things" that don't work and improve the failed things. Never mind that if procedure 10 failed, you never get to test procedure 11+. So your next launch fails at procedure 11. It's just a bad attitude.

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

#38

Post by s1artibartfast »

areoform wrote: post #16
jjmarr wrote: post #14

Earlier 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 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.

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

#39

Post by ceejayoz »

mystified5016 wrote: post #30
dist-epoch wrote: post #4

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.

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

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

$32k/kilo or so.

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

#40

Post by JshWright »

ceejayoz wrote: post #8
1970-01-01 wrote: post #7

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

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.
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