Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

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

arstechnica.com

Post reply on HN
Print view View original

81–90 of 277 posts

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

#81

Post by _bin_ »

JshWright wrote: post #40
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.

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.

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.

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

#82

Post by JumpCrisscross »

sandworm101 wrote: post #80
JumpCrisscross wrote: post #61

Earlier quoted context omitted.

> Just wait for SpaceX to start trying to land starships on the moon. Also vertically SpaceX has done it. To date, other nation-states have tried and failed to replicate their achievements in this domain. IM’s design is wrongly optimised and probably requires a rethink. That the CEO won’t contemplate this isn’t a great sign for the company.

Lol. SpaceX has landed on prepared surfaces, concrete pads on land or on large barges. They literally have a big X to mark the target. Let's see them land on some random beach, an uneven surface that may or may not subside. But that is still peanuts comparted to the moon's surface.

> that is still peanuts comparted to the moon's surface

Sure. I'm not trivialising the problem in an absolute sense. Just going from floating barge or chopsticks to Moon is a simpler set of problems than reïnventing the sort of translational velocity and attitude control needed to get to first base.

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

#83

Post by Aspos »

ceejayoz wrote: post #46
1970-01-01 wrote: post #45

Earlier quoted context omitted.

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.

May it be that laser bounced off exhaust plume?

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

#84

Post by sandworm101 »

JumpCrisscross wrote: post #82
sandworm101 wrote: post #80

Earlier quoted context omitted.

Lol. SpaceX has landed on prepared surfaces, concrete pads on land or on large barges. They literally have a big X to mark the target. Let's see them land on some random beach, an uneven surface that may or may not subside. But that is still peanuts comparted to the moon's surface.

> that is still peanuts comparted to the moon's surface Sure. I'm not trivialising the problem in an absolute sense. Just going from floating barge or chopsticks to Moon is a simpler set of problems than reïnventing the sort of translational velocity and attitude control needed to get to first base.

For selecting and touching down on an unprepared surface, rockets are not the stepping stone. Start with helicopters. It is the same problem: can I land there and what will happen when I put weight on the surface. Try programing a large helicopter to identify and land on a random chunk of rocky terrain. It is not easy. And the bigger/taller the craft, the more difficult it becomes. Then add a 10-second time limit.

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

#86

Post by usrnm »

scotty79 wrote: post #73
Koshkin wrote: post #58

Earlier quoted context omitted.

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

I refuse to believe anyone knows how cold -280F is. When you have such extreme temperatures you think in Kelvin or at least Celsius.

It's not like using Kelvin or Celsius helps you grasp these temperatures. -173C is very, very cold, but how cold? What can you compare it to? Not many humans have any experience with something of this scale

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

#87

Post by MegaButts »

JumpCrisscross wrote: post #67
CamperBob2 wrote: post #65

Earlier quoted context omitted.

SpaceX has done it. SpaceX has landed Starship on the moon?!

SpaceX has repeatedly and reliably landed vertical stacks. On any body. Out of the engineering problems inherent to HLS, sticking the landing isn’t material because for them, for that team, it isn't as novel a problem as e.g. in-orbit refuelling or getting Raptors to relight on the Moon. Put another way, just because SpaceX has done it doesn't mean the same problem carries the same risk for a team like IM's.

Has SpaceX ever landed their rocket on a surface that isn't purposefully engineered to be flat?

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

#88

Post by antonvs »

littlestymaar wrote: post #66

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?)

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).

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

#89

Post by layer8 »

dietr1ch wrote: post #62
layer8 wrote: post #37

Earlier quoted context omitted.

It’s roughly a third of room temperature.

Which is hard to grok since a third of something warm doesn't seem to be extremely cold.

It’s sort-of the point to realize that it actually is (a third of something). The lander is receiving a third of the thermal energy that it would receive at room temperature.

Warm-blooded mammals of course have a reference point based on their thermal homeostatic capabilities (ability to maintain body temperature). “Warm” and “cold” is in relation to that.

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

#90

Post by alwayslikethis »

usrnm wrote: post #86
scotty79 wrote: post #73

Earlier quoted context omitted.

I refuse to believe anyone knows how cold -280F is. When you have such extreme temperatures you think in Kelvin or at least Celsius.

It's not like using Kelvin or Celsius helps you grasp these temperatures. -173C is very, very cold, but how cold? What can you compare it to? Not many humans have any experience with something of this scale

Liquid nitrogen (boiling at -196 C) is a semi-common substance that people would have heard of, though not everyone would have seen or interacted with it.
Post reply on HN