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Artemis II Launch Day Updates

nasa.gov

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Re: Artemis II Launch Day Updates

#681

Post by SyzygyRhythm »

JumpCrisscross wrote: post #300

April 6: flyby April 10: splashdown After that, the exciting work will be in Starship making LEO and testing propellant transfer (a humanity first) [1] and Blue Origin testing its rocket and lunar lander [2], both scheduled for 2026, to enable Artemis II (EDIT: III), currently scheduled—optimistically, in my opinion—for next year. [1] https://en.wikipedia.org/wiki/List_of_Starship_launches#Futu... [2] https://en.wiki…

Starship "making LEO" is not a significant challenge--the existing flights have explicitly targeted a (very slightly) suborbital trajectory. They could have done otherwise at any point, but for now it's more important to guarantee that the stage comes down immediately. None of their current objectives require more than ~1/2 of an orbit.

Starship v3 flying will be a significant leap, though. It's the first with the Raptor v3 engines and has many other improvements as well, such as updated grid fins and hot staging ring. It will be the first that achieves close to the intended capacity of ~100 tons.

Propellant transfer is indeed a significant challenge. They have already demonstrated internal transfers between tanks, but not between spacecraft.

Very exciting times ahead!

Re: Artemis II Launch Day Updates

#682

Post by vscode-rest »

reactordev wrote: post #662
layer8 wrote: post #538

Earlier quoted context omitted.

It’s absolute in the sense that you can determine your acceleration without any external reference. You feel a certain force (like what you feel in an elevator). That’s your acceleration. You don’t accelerate relative to Earth, or relative to anything else. You accelerate relative to when you wouldn’t be accelerating (your inertial rest frame, a state of free fall). If you are in space accelerating and the Earth woul…

"You feel a certain force" is that true in zero-g?

[dead]

Re: Artemis II Launch Day Updates

#683

Post by JumpCrisscross »

bee_rider wrote: post #645
JumpCrisscross wrote: post #223

Earlier quoted context omitted.

> Whether a moon base is needed or even beneficial is a question I have not heard a convincing answer in favor If we want to go to Mars, the Moon is a good place to learn. Simple things like how to do trauma medicine in low g; how to accommodate a variety of human shapes, sizes and fitness levels; how to do in situ manufacturing; all the way to more-speculative science like how to gestate a mammal. These are easier t…

I think I mostly agree with the other comment by runarberg—Earth is the place to be. But it is also worth noting that even if we do end up colonizing space, Mars is still really pointless. Mars is not significantly more habitable than orbit. There’s some gravity: the wrong amount. In space, you can at least get 1G with centripetal force. In orbit, you are halfway to anywhere. On Mars, you’ve gone back down the well.…

> Earth is the place to be. But it is also worth noting that even if we do end up colonizing space, Mars is still really pointless. Mars is not significantly more habitable than orbit

I’m not pitching a specific destination. And I’m not pitching exploration to the masses. Most people on the planet never have and never will leave their home country.

If we want to go to space, we probably want a lunar base.

> There’s some gravity: the wrong amount. In space, you can at least get 1G with centripetal force

Maybe this is important. Maybe it’s not. We need physiological experiments.

> In orbit, you are halfway to anywhere. On Mars, you’ve gone back down the well

In orbit you’re perpetually nowhere. On a surface you have in situ resources.

> Mars is just a bunch of irradiated rocks. Bring your own ecosystem, and wait a couple thousand years while it installs

Maybe it’s age. Maybe it’s moving from New York to Wyoming. Maybe those are the same thing. But I’m more of a red Mars advocate today than I was when I read Robinson’s trilogy in my twenties.

> only thing Mars has going for it is that it’s really far away, so we can still pretend to entertain sci-fi plans about colonizing it

It’s mass and an atmosphere. That’s a lot to what Earth has going for us.

> practical next step for space colonies would be large investments in additional space stations

Practical next steps are lots of experiments in centrifuges and micro and low gravity. To fund and focus that you need a goal.

Re: Artemis II Launch Day Updates

#684

Post by Teever »

JumpCrisscross wrote: post #559
Teever wrote: post #537

Earlier quoted context omitted.

All of this stuff is really great but it's not worth the cost that was spent on it. The thing you have to keep asking yourself is "what could 100 billion dollars of non-pork barrel spending have bought instead of what we ended up with?"

> All of this stuff is really great but it's not worth the cost that was spent on it It’s building towards a system. If we get Starship and in-orbit propellant depots and a lunar nuclear reactor and then kill the programme, it will probably be judged by history as a success. > what could 100 billion dollars of non-pork barrel spending have bought instead of what we ended up with? Rien . This is the system we have, an…

It may be building towards a system. Or it could all be cancelled in 3-4 weeks after these four explorers burn up on reentry.

And then all these hopes and dreams that you have will be gone, like that $100 billion dollars just up in smoke.

I can tell that you're as passionate about space exploration and colonization as I am, but this isn't the way my friend.

This program is coming at the cost of the Aldrin Cyclers and Von Braun Wheels that you and I know could and should have existed decades ago and while you may think that those things will come from this program I think you should consider the fact that root cause of this program's dysfunction is what is denying us this reality of humanity spreading across the stars.

Re: Artemis II Launch Day Updates

#685

Post by JumpCrisscross »

ls65536 wrote: post #658
JumpCrisscross wrote: post #644

Earlier quoted context omitted.

> ABC News says 330 habitable cubic feet or about the interior space of two minivans I did lockdown in a ~450 sq. ft. Habitable under 400. Partner. Cat. Me. The astronauts will be fine.

~450 square feet, with how many feet in the third dimension? You probably had an order of magnitude more volume than 330 cubic feet there.

> You probably had an order of magnitude more volume than 330 cubic feet there

I’m 6’, so that’s the usable volume. (I’m not claustrophobic heighwise.)

I honestly don’t see an issue spending a couple days with folks I respect and admire in close quarters for ten days.

Re: Artemis II Launch Day Updates

#686

Post by Teever »

idiotsecant wrote: post #620
Teever wrote: post #537

Earlier quoted context omitted.

All of this stuff is really great but it's not worth the cost that was spent on it. The thing you have to keep asking yourself is "what could 100 billion dollars of non-pork barrel spending have bought instead of what we ended up with?"

What a simultaneously cynical and boring and completely useless attitude. Is it your position that if this hadn't happened 100b of otherwise more important spending would have happened?

I think that $100 billion, spent effectively could have resulted in Von Braun Wheels in LEO. I think that it could have resulted in teleoperated lunar mining and smelting that would be allowing us to build human bases on Earth now instead of a single fly by that may end in the death of these four amazing explorers.

Re: Artemis II Launch Day Updates

#687

Post by gammarator »

areoform wrote: post #207
dekhn wrote: post #173

Earlier quoted context omitted.

Are you referring to https://en.wikipedia.org/wiki/Troctolite_76535 ( https://en.wikipedia.org/wiki/Harrison_Schmitt#NASA_career )?

Yes, and more! > Apollo was over three orders of magnitude more efficient in producing scientific papers per day of fieldwork than are the MERs. This is essentially the same as Squyres’ (2005) intuitive estimate given above, and is consistent with the more quantitative analogue fieldwork tests reported by Snook et al. (2007). Scientific papers are a pretty poor measure of productivity so here's another one. We know a…

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

Re: Artemis II Launch Day Updates

#688

Post by kd0amg »

lionkor wrote: post #515
layer8 wrote: post #459

Earlier quoted context omitted.

Maybe you’ll like this too: The Earth’s speed around the sun is around 67,000 mph. So it moves significantly faster than the rocket, though not orders of magnitude. The solar system itself moves at 43,000 mph relative to its local neighborhood. But speed is always just relative to some frame of reference. Acceleration, on the other hand, is absolute, and so might be the more interesting thing to look at here.

Acceleration is change in speed, so it is, by its very nature, relative just like speed is. If I fall, I might accelerate at G meters per second, relative to the earth, but I don't absolutely accelerate. If the earth decelerates at the same time, I'm now both accelerating an decelerating. It's relative.

Think of it more as "speed is the indefinite integral of acceleration" with the extra constant denoting a choice of inertial reference frame.

Re: Artemis II Launch Day Updates

#689

Post by cdot2 »

healthworker wrote: post #667
mcmcmc wrote: post #651

Earlier quoted context omitted.

[flagged]

Do you prefer that we not even try to spread beyond our one planet, when an entire galaxy, or maybe even the neighboring ones, might be in reach if we try? What if someday at the very end of the lifetime of our sun and similar stars, we look back, and regret not trying?

There have always been lame people like this and for all of human history we have continued to explore and expand. I think at this point those people can safely be ignored.

Re: Artemis II Launch Day Updates

#690

Post by JumpCrisscross »

Teever wrote: post #684
JumpCrisscross wrote: post #559

Earlier quoted context omitted.

> All of this stuff is really great but it's not worth the cost that was spent on it It’s building towards a system. If we get Starship and in-orbit propellant depots and a lunar nuclear reactor and then kill the programme, it will probably be judged by history as a success. > what could 100 billion dollars of non-pork barrel spending have bought instead of what we ended up with? Rien . This is the system we have, an…

It may be building towards a system. Or it could all be cancelled in 3-4 weeks after these four explorers burn up on reentry. And then all these hopes and dreams that you have will be gone, like that $100 billion dollars just up in smoke. I can tell that you're as passionate about space exploration and colonization as I am, but this isn't the way my friend. This program is coming at the cost of the Aldrin Cyclers and…

> It may be building towards a system

It may build. It is building.

> it could all be cancelled in 3-4 weeks after these four explorers burn up

We’d have wasted money. But we’d still be ahead. Artemis has funded a lot of development.

> can tell that you're as passionate about space exploration and colonization as I am, but this isn't the way my friend

In a perfect world? No. Is it a legitimate way? Absolutely. We’re still moving forward.

> This program is coming at the cost of the Aldrin Cyclers and Von Braun Wheels

Nobody is funding these. We’re beating the Chinese to land. That clicks. That sells. Space-based infrastructure is hallucinated competition.

> that root cause of this program's dysfunction is what is denying us this reality

The alternative is we spend NASA’s Artemis budget on Medicaid billing at autism centers in Indiana.

I’d prefer the vision you painted. But I won’t let perfect be the enemy of the good. This program moves us forward and funds roads to alternatives. Starship, for example.

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