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

arstechnica.com

181–190 of 277 posts

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

#181

Earlier quoted context omitted.

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

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

There's tons... Firefox: https://addons.mozilla.org/en-US/firefox/addon/clearurls/ Android: https://github.com/svenjacobs/leon

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

#182

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.

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.

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

#183
post #17

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. A…

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

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

#185
post #26

Earlier quoted context omitted.

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 gra…

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)

Buried "mascons" (mass concentrations), https://en.wikipedia.org/wiki/Gravitation_of_the_Moon has some nice color maps of the deviations/anomalies. (TLDR: some of it is explained by basalt but not all of it, and it's still being studied, because it interferes with low altitude lunar orbits.)

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

#186

Earlier quoted context omitted.

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

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

Just in case, I’m using my own violentmonkey scripts rather than hoping for extensions, and everyone can do that too (now only on firefox, I guess, and maybe brave).

For example, I remove &t= from urls that youtube added recently in addition to regular watch position restoration. This broke it for me and they don’t seem to plan a revert.

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

#187
post #135

Earlier quoted context omitted.

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.

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.

I noticed it didn't have the Celsius value at the beginning, and a while later I noticed it was there. But "minus 280 F / 173 C" is terrible formatting, it looks like it's positive in Celsius...

Considering the conversion between the 2 temperature scales can flip the sign (e.g. -10C is 14F), "-280F/-173C" would've been a lot clearer.

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

#189

Earlier quoted context omitted.

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.

Any moderately active satellite has far more issues with excess heat

It depends on the size of the satellite and its power use. Small spacecraft often don't use enough power to generate enough heat to warm themselves. The problem then is batteries get cold (which is one of the places you need heaters) and become inefficient and then you end up in death spiral. Here the probe likely wasn't generating enough power anyway, so that would almost certainly kill it before the cold.

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

#190
post #178

Earlier quoted context omitted.

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.

>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.

Is that really "space" as opposed to "the lingering effects of the big bang"? (or less interestingly, the temperature of the CMB photon gas)
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