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Artemis II Launch Day Updates

nasa.gov

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Re: Artemis II Launch Day Updates

#841

Post by ACCount37 »

jojobas wrote: post #823
JumpCrisscross wrote: post #820

Earlier quoted context omitted.

> They are persisting with HLS though Through what? What experimental data do you think renders this path foolish? Because I’m seeing a rapid-reuse heavy lift system with a fuel depot being built.

I dunno, the fact that nobody can say how many fuel launches a moonshot is going to take, but at least 12? And that the lunar orbit chosen due to available energy makes rapid extraction impossible?

"How many fuel launches" is the error margin.

If they get less performance or more mission payload, they can add tanker launches. If they get more performance or less mission payload, they can remove tanker launches.

People ran into "the design is 10% heavier than planned for unexpected engineering reasons and now we have to make hard choices" on space missions far less complex than a literal Moon landing. SpaceX has externalized the "hard choices" into the tanker count, pre-emptively.

The lunar orbit of Artemis is defined mainly by SLS/Orion's performance, or lack of thereof. The specific NRHO was a Gateway choice, and might now be dead alongside it, but by itself, Orion can't get to low Lunar orbit. Which drives some peculiar design choices.

Re: Artemis II Launch Day Updates

#842

Post by amai »

sd9 wrote: post #320

Minutes after launch they reached "ten thousand miles per hour". That's 2.78 miles per second. Nuts. No doubt the speeds go even higher later too. I'm sure people here are already familiar with the speeds these things go, but that's the first time I've confronted a fact like that and it blew me away.

NASA uses metric units even under Trump. So this is 16093 km/h or 4.474 km/s .

Re: Artemis II Launch Day Updates

#843

Post by prohobo »

pineaux wrote: post #836
prohobo wrote: post #821

Earlier quoted context omitted.

Ughhh, Elon Moosk amirite? Such a fraud, because [???] I don't really understand why these kinds of comments persist except as some pathological cope when confronted with a world that doesn't work the way you want it to. It's not convincing, it immediately outs you as a zealot, it's counterproductive in every single way. Why keep doing it?

just saying: he is good at vaporware on a large scale and kind of a fucked up person. It's not weird people are skeptical. But he also has basically an endless money supply so he can throw money at problems and make them go away eventually. But his timelines are basically all lies used to get venture and retail money into the game.

That describes basically all founders though, minus the endless money supply. That's how business/sales works: make promises, build product later.

Also SpaceX, Tesla, PayPal, OpenAI, Grok and Neuralink aren't vaporware...

The claim fundamentally doesn't make any sense.

Re: Artemis II Launch Day Updates

#845

Post by ben_w »

JumpCrisscross wrote: post #741
p1mrx wrote: post #715

Earlier quoted context omitted.

According to general relativity, you (and the ground) are accelerating at 1g, and feel weight because your inertia resists that acceleration. If you jump off a cliff, you'll stop accelerating for a bit, until the ground hits you. Edit to reply: > I am standing on the ground. I feel 1G acceleration. My speed is not changing. How much am I accelerating? You are accelerating at 1g through curved spacetime. Newtonian "sp…

> According to general relativity, you (and the ground) are accelerating at 1g I don't believe this is correct. If I lock two rockets in opposition to each other, they aren't accelerating. They're pushing at each other. And their propellant is accelarating away. But their displacement and orientation are unchanging, which means their velocity is zero which means acceleration isn't happening. Similarly, the normal for…

As I understand it, in GR acceleration is indistinguishable* from gravity, so while you're on the ground feeling 1 gee, you're being accelerated up at 1 gee, and so is the ground.

When you're in free-fall, that's when you're in a non-accelerating frame, even though a non-relativistic description** would say that you are, in fact, accelerating.

Caveat: I only do physics as a hobby, neither academically nor professionally, so take with appropriate degree of doubt.

* for point-like observers at least

** ignoring rotation and curved orbits

Re: Artemis II Launch Day Updates

#846

Post by ainch »

dotancohen wrote: post #726
gammarator wrote: post #687

Earlier quoted context omitted.

You’ve got to normalize by dollars spent, though.

If your goal is to save money, just ignore the moon. This is not the west indies to be exploited, at least not yet. These are scientific missions, not economic missions. The philosopher Randall Munroe once wrote: > The universe is probably littered with the one-planet graves of cultures which made the sensible economic decision that there's no good reason to go into space - each discovered, studied, and remembered by…

Randall Munroe of xkcd? I like his work but I'm not sure I'd call him a philosopher...

Re: Artemis II Launch Day Updates

#847

Post by JumpCrisscross »

pwndByDeath wrote: post #840
JumpCrisscross wrote: post #691

Earlier quoted context omitted.

> Starship "making LEO" is not a significant challenge Of course it is. I say this as someone who sturdied astronautics. You’re broadly correct, though. My point is the action shifts to Hawthorne and West Texas for the next year or so. Then pivots back to NASA for Artemis IV.

"Project Gemini has entered the chat." Did I do that right? Anyway, what are we talking about?

> Did I do that right?

Unless you’re trying to make a reference to the Gemini programme. No.

Re: Artemis II Launch Day Updates

#848

Post by JumpCrisscross »

prohobo wrote: post #821
jojobas wrote: post #802

Earlier quoted context omitted.

> But they’re ridiculously good at not persisting with stupid. They are persisting with HLS though.

Ughhh, Elon Moosk amirite? Such a fraud, because [???] I don't really understand why these kinds of comments persist except as some pathological cope when confronted with a world that doesn't work the way you want it to. It's not convincing, it immediately outs you as a zealot, it's counterproductive in every single way. Why keep doing it?

> don't really understand why these kinds of comments persist

One, you can make money criticizing Elon on the internet.

Two, controversy is catnip to the man. DOGE was a disaster. X and xAI look like aborted disasters. And he’s clearly gotten bored with Tesla. It isn’t hard to project that on SpaceX if you don’t know the heritage.

Re: Artemis II Launch Day Updates

#849

Post by karmakurtisaani »

chromacity wrote: post #653
MarkusWandel wrote: post #583

Earlier quoted context omitted.

When I see numbers like that ($38 billion) thrown around I always wonder: Where did that money go? In the best case, it stayed in the economy in the form of salaries and such. In the worst case, it goes directly into an offshore pile of mega-wealth where it won't benefit the economy and likely won't even be taxed. Is there any way to determine where on this continuum this program stands? I'm guessing the 1960s space…

That kind of money, even if it goes to a single person, doesn't get taken out of the economy. No one puts it under the mattress. It's invested, so it's basically given to other people in exchange for a promise of equity / future returns. It might not be the allocation of capital we like, but it doesn't disappear.

> No one puts it under the mattress. It's invested, so it's basically given to other people in exchange for a promise of equity / future returns.

You make wealth concentration sound like a good thing somehow. This was publicly collected tax money, that will go on to enrich some already rich douchebag.

Re: Artemis II Launch Day Updates

#850

Post by renewiltord »

duped wrote: post #80
lp0_on_fire wrote: post #34

Earlier quoted context omitted.

Artemis was already set in stone well before DOGE came about and IMO if the federal government is going to set mountains of cash on fire I'd rather it be to NASA than half the crap the government wastes every year.

My point is that DOGE killed a bunch of government programs that help people while saving no money, yet this giant waste of money survived. Cancelling Artemis II alone in favor of III would save a billion dollars by itself.

Guy who runs space program joins government to kill his competitor would be a beautiful story.
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