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Artemis II Launch Day Updates

nasa.gov

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Re: Artemis II Launch Day Updates

#731

Post by kortilla »

JumpCrisscross wrote: post #691
SyzygyRhythm wrote: post #681

Earlier quoted context omitted.

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 Ra…

> 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.

It’s not a significant challenge compared to what they’ve already done.

Each of those previous tests could have easily gone to LEO running the engines just a tiny bit longer.

OPs point is that they intentionally didn’t.

achieving LEO means you need a relight to have a controlled reentry. You don’t want that if you want to avoid countries being mad at you while you iron out those controls

Re: Artemis II Launch Day Updates

#732

Post by dirasieb »

krapp wrote: post #612
WaterRun wrote: post #599

Earlier quoted context omitted.

Developing something like this would push the frontiers of human technology. Without the Apollo program, not to mention anything else, the personal computer boom in the 1970s might have been delayed by a long time.

We're redoing things we did before most people in this thread were even born, how would any of this "push the frontiers of human technology?"

>We're redoing things we did before most people in this thread were even born

oh really? show me a picture of the dark side of the moon then

not a reconstruction, not touched up crap based on data like that black hole pic that went viral a few years ago, an actual photograph taken by an astronaut of the dark side of the moon

Re: Artemis II Launch Day Updates

#733

Post by wileydragonfly »

vjvjvjvjghv wrote: post #547

The camera work was just terrible. They really need to learn from SpaceX how to do this right. Minus the obnoxious cheering. SpaceX does these beautiful drone shots and live telemetry so well. Considering that each SLS launch costs in the billions it would be nice to do a little better on production I felt the commentary during the launch also wasn't good. And I am not too interested in hearing from some Hollywood pe…

[flagged]

Re: Artemis II Launch Day Updates

#734

Post by bch »

Is anybody aware of audio-only coverage of this mission? I'd have loved to just tuned into most of the launch like radio, rather than having my unwatched youtube running.

Re: Artemis II Launch Day Updates

#735

Post by hcs »

marcus_holmes wrote: post #721
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…

I am standing on the ground. I feel 1G acceleration. My speed is not changing. How much am I accelerating?

You are more quickly being carried by the ground further from where you would otherwise be. Hope that clears it up.

Re: Artemis II Launch Day Updates

#736

Post by JumpCrisscross »

kortilla wrote: post #731
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.

It’s not a significant challenge compared to what they’ve already done. Each of those previous tests could have easily gone to LEO running the engines just a tiny bit longer. OPs point is that they intentionally didn’t. achieving LEO means you need a relight to have a controlled reentry. You don’t want that if you want to avoid countries being mad at you while you iron out those controls

> It’s not a significant challenge compared to what they’ve already done

I don't know an aersospace engineer, within SpaceX or without, who would agree. When you increase speeds you increase energies faster. That has an effect on everything from pump performance to re-entry physics.

> Each of those previous tests could have easily gone to LEO running the engines just a tiny bit longer

Which risks recovery. Given they were replacing their Raptors in the next refresh, pushing an already-obsolete engine for shits and giggles doesn't make sense when you can get good data on e.g. skin performance.

> achieving LEO means you need a relight to have a controlled reentry. You don’t want that if you want to avoid countries being mad at you while you iron out those control

There is zero indication diplomatic pressure has been a constraint on the U.S. space programmes in the last couple years.

Re: Artemis II Launch Day Updates

#737

Post by storus »

bee_rider wrote: post #42
runarberg wrote: post #36

Earlier quoted context omitted.

I think there is a major difference though. Sports events are not pretending to be anything else. The Artemis mission claims to be advancing science and claims to be a stepping stone for an eventual moon base and a manned mission to Mars. I personally have serious questions about all of these.

I don’t have any questions about a mission to Mars, it is a stupid and pointless trip that I don’t want to ask any questions about. The Moon, I dunno, it’s at least in Earth’s gravity well so it isn’t like we’re going totally the wrong direction when we go there, right? At best it could be a gas station on the trip to somewhere interesting like the Asteroid belt, though.

Mars pushes the frontier (even if no one might survive the trip due to human body deteriorating), going around the Moon is meh - we were there ~57 years ago multiple times so what's the point?

Re: Artemis II Launch Day Updates

#739

Post by bryanlarsen »

JumpCrisscross wrote: post #736
kortilla wrote: post #731

Earlier quoted context omitted.

It’s not a significant challenge compared to what they’ve already done. Each of those previous tests could have easily gone to LEO running the engines just a tiny bit longer. OPs point is that they intentionally didn’t. achieving LEO means you need a relight to have a controlled reentry. You don’t want that if you want to avoid countries being mad at you while you iron out those controls

> It’s not a significant challenge compared to what they’ve already done I don't know an aersospace engineer, within SpaceX or without, who would agree. When you increase speeds you increase energies faster. That has an effect on everything from pump performance to re-entry physics. > Each of those previous tests could have easily gone to LEO running the engines just a tiny bit longer Which risks recovery. Given they…

They didn't have to increase speeds, they already achieved orbital velocity. To circularize all they need to do is relight. Relighting an engine is very difficult for an engine like Raptor, but they've already demonstrated relight.

Re: Artemis II Launch Day Updates

#740

Post by JumpCrisscross »

bryanlarsen wrote: post #739
JumpCrisscross wrote: post #736

Earlier quoted context omitted.

> It’s not a significant challenge compared to what they’ve already done I don't know an aersospace engineer, within SpaceX or without, who would agree. When you increase speeds you increase energies faster. That has an effect on everything from pump performance to re-entry physics. > Each of those previous tests could have easily gone to LEO running the engines just a tiny bit longer Which risks recovery. Given they…

They didn't have to increase speeds, they already achieved orbital velocity. To circularize all they need to do is relight. Relighting an engine is very difficult for an engine like Raptor, but they've already demonstrated relight.

> They didn't have to increase speeds, they already achieved orbital velocity

My undertstanding is Starship didn't hit 17,000 mph [1]. LEO orbits tend to be 17,500 mph and up.

Like, I'm not arguing that SpaceX couldn't have circularised on previous tests. But it would have added material risk without any reward. And taking a ship, particularly a re-usable one, particularly a novel one, into its first orbital flight is always exhausting and novel.

[1] https://www.thespacereview.com/article/4761/1#:~:text=As%20S...

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