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Athena spacecraft declared dead after toppling over on moon

theguardian.com

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Re: Athena spacecraft declared dead after toppling over on moon

#111

Post by bombcar »

bawolff wrote: post #110
bombcar wrote: post #82

Earlier quoted context omitted.

Private large old round blue American metallic robotic spaceship. Sounds a bit wrong, I want to put American first.

Otoh, if you cut out some - "old american spaceship" sounds fine to me, where "american old spaceship" does not (or it makes it sound like "american old" is a brand name)

Part of it might be that the age is changing, but the "American" isn't.

I don't know. It's weird that there's obviously some kind of ruleset here, but it's difficult to nail it down.

Re: Athena spacecraft declared dead after toppling over on moon

#112

Post by bluGill »

BugsJustFindMe wrote: post #91
dreamcompiler wrote: post #78

Good advice: 1. Never invade Russia in winter. 2. Make sure your robotic lunar lander has a low center of gravity.

> Never invade Russia in winter. I thought it was never get involved in a land war in Asia.

There are been lot of land wars in Asia over history. Sometimes it goes well for the defender, sometimes the attacker.

Never get involved in a war is good advice, but sometimes impossible to keep.

Re: Athena spacecraft declared dead after toppling over on moon

#113

Post by ForOldHack »

kulahan wrote: post #95
rrr_oh_man wrote: post #85

Earlier quoted context omitted.

Upvoted, but just wanted to say it explicitly: What an in-depth and thoughtful answer. Thank you for this!

Comments like these are literally why I come to HN honestly. It’s such a wonderful community here.

They are especially flavorful recently.

Re: Athena spacecraft declared dead after toppling over on moon

#115

Post by kristianp »

sho_hn wrote: post #24
nine_k wrote: post #2

One similarly structured craft (thin and tall) reached the Moon a year ago, and also eventually toppled. Maybe next missions will feature less tower-shaped designs and more crab-shaped designs, at least during the landing phase.

Which gives me great amusement about the current human spaceflight plan to land upright Starship on the moon, and lower astronauts from the top of what is effectively a tower-like 13-story building (52.1m without landing legs, at 9m tube width) using some kind of elevator solution. To put things into perspective, this is roughly the same height as the Leaning Tower of Pisa, and with landing legs extended probably abo…

At least they're likely to do unmanned test landings until they successfully land upright. But it seems nobody followed the design of the appollo lander, except the Blue ghost which landed successfully last week.

Re: Athena spacecraft declared dead after toppling over on moon

#116

Post by mathgeek »

JoeAltmaier wrote: post #105
arccy wrote: post #92

Earlier quoted context omitted.

when gravity is 1/6, a lower centre of gravity might not do as much as you think

I think that is entirely irrelevant. It just changes the speed of the topple. Does not affect at all the tendency to tip over?

It's been a while, but IIRC when we assume all other variables as constant, a lower center of mass (a) will decrease the denominator and thus increase the resulting necessary tipping force.

Fₜ = (m × g × cos(θ) × b) / (a + b)

Re: Athena spacecraft declared dead after toppling over on moon

#117

Post by macintux »

mmooss wrote: post #101
sho_hn wrote: post #43

Earlier quoted context omitted.

250 meters is very respectable for a first try. Apollo 14 and 12 achieved 30 meters and 163 meters with human piloting, respectively, and that's after the program made precision landing a high-effort mission goal. The automated missions of the 60s-70s were often off target by a kilometre or more, but Surveyor 3 came in within 200 meters as well in '67. Japan did a mission in 2024 with the express purpose of achieving…

Is 50 year old technology and expertise a good standard for comparison for modern tech?

I'd say relative to the difficulty of accuracy, the hostility of the environment, the known "lumpiness" of the moon, and the challenges of testing any of it in advance...yes?

Re: Athena spacecraft declared dead after toppling over on moon

#118

Post by hansvm »

JoeAltmaier wrote: post #105
arccy wrote: post #92

Earlier quoted context omitted.

when gravity is 1/6, a lower centre of gravity might not do as much as you think

I think that is entirely irrelevant. It just changes the speed of the topple. Does not affect at all the tendency to tip over?

Adding to the sibling @mathgeek's comment, that's only true when there are no outside forces other than gravity. You can see that by taking the counter-argument to its extreme: with gravity of epsilon, even a gentle prod at the top of the object will topple it over.

Re: Athena spacecraft declared dead after toppling over on moon

#120

Post by smj-edison »

spelunker wrote: post #87
nine_k wrote: post #2

One similarly structured craft (thin and tall) reached the Moon a year ago, and also eventually toppled. Maybe next missions will feature less tower-shaped designs and more crab-shaped designs, at least during the landing phase.

I mean, eventually everything is crab right?

Mandatory xkcd 2314.
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