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Artemis I Launch Attempt Scrubbed

blogs.nasa.gov

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Re: Artemis I Launch Attempt Scrubbed

#81

Post by endymi0n »

theteapot wrote: post #78
endymi0n wrote: post #73

Does anyone get the point with Artemis? Because I really don‘t. To my untrained eye the current outlook on the program looks like that rocket is right now only supposed to make two roundtrips along the moon — and then in that third „Starship HLS“ mission Artemis’ only job is to take up the astronauts to orbit: while Starship (notably designed to be human rated) will be doing all the heavy lifting of the mission. In t…

> Does anyone get the point with Artemis? Because I really don‘t. They want to go to the moon.

That‘s exactly what I mean. In their newest plan, they don’t. Someone else does.

Re: Artemis I Launch Attempt Scrubbed

#82

Post by engineer_22 »

endymi0n wrote: post #73

Does anyone get the point with Artemis? Because I really don‘t. To my untrained eye the current outlook on the program looks like that rocket is right now only supposed to make two roundtrips along the moon — and then in that third „Starship HLS“ mission Artemis’ only job is to take up the astronauts to orbit: while Starship (notably designed to be human rated) will be doing all the heavy lifting of the mission. In t…

When they started the project (2011) Starship wasn't even a twinkle in Elon's eye (BFR around 2016). Starship started looking like a real product in 2020. In hindsight, you're right, SLS looks silly, but not many people were betting on SpaceX developing a super heavy launch system in 6 years like they've (apparently) done. They've invested a lot of money in SLS and there's probably still lessons to learn there. If Starship is successful SLS will probably not be deployed very frequently.

Re: Artemis I Launch Attempt Scrubbed

#83

Post by huhtenberg »

theteapot wrote: post #78
endymi0n wrote: post #73

Does anyone get the point with Artemis? Because I really don‘t. To my untrained eye the current outlook on the program looks like that rocket is right now only supposed to make two roundtrips along the moon — and then in that third „Starship HLS“ mission Artemis’ only job is to take up the astronauts to orbit: while Starship (notably designed to be human rated) will be doing all the heavy lifting of the mission. In t…

> Does anyone get the point with Artemis? Because I really don‘t. They want to go to the moon.

They want to keep lots of people employed.

Re: Artemis I Launch Attempt Scrubbed

#84

Post by theteapot »

Teever wrote: post #50
yarpnird wrote: post #43

Earlier quoted context omitted.

Think about all the work done by people that you are discounting...

What is the point that you're trying to make here? I'm sure we've all experienced situations where we realize that the work we're being paid to do is futile and will never reach achieve it's intended purpose. It's really demoralizing but the thing to remember in that situation is that you're still getting paid. Would you rather be an aeronautical engineer who gets paid and doesn't launch of a rocket, or an aeronautic…

> ... the thing to remember in that situation is that you're still getting paid.

That's the spirit.

Re: Artemis I Launch Attempt Scrubbed

#85

Post by theteapot »

endymi0n wrote: post #81
theteapot wrote: post #78

Earlier quoted context omitted.

> Does anyone get the point with Artemis? Because I really don‘t. They want to go to the moon.

That‘s exactly what I mean. In their newest plan, they don’t. Someone else does.

Who? They're all on the same team, team USA! Or are you implying the glacial pace will inevitably mean China gets there first?

Re: Artemis I Launch Attempt Scrubbed

#86

Post by pengaru »

melling wrote: post #39
IshKebab wrote: post #29

Earlier quoted context omitted.

IMDB disagrees! 6.2.

6.2 isn’t good but this is a John Carpenter movie, written and directed. In fact, it was his student film. Looks like he was going for a 2001 A Space Odyssey feel.

> Looks like he was going for a 2001 A Space Odyssey feel.

I thought he was communicating just how _boring_ and time consuming space exploration will be, being such vast emptiness.

Re: Artemis I Launch Attempt Scrubbed

#87

Post by theteapot »

allenrb wrote: post #9

Consequences of choosing the wrong first stage fuel (hydrogen) are many. Those tiny molecules want nothing more from life than to sneak through the smallest of openings. Well, possibly second to mating violently with oxygen.

Worked pretty well for 135 shuttle missions.

Re: Artemis I Launch Attempt Scrubbed

#88

Post by mabbo »

adastra22 wrote: post #65
mabbo wrote: post #21

Earlier quoted context omitted.

Like all engineering decisions, hydrogen is a choice with tradeoffs. It's specific impulse ('fuel efficiency') is unbeatable. That buys you a lot more cargo capacity for the same sized rocket. And since this program is putting large items into lunar orbit, you need that badly. But as you said, it's... complex to work with. Hey it worked for the space shuttle.

> That buys you a lot more cargo capacity for the same sized rocket. I think you mean the same mass rocket, because hydrogen is not dense, which factors into the tradeoffs (more structural mass to contain it).

An excellent point.

Fortunately bigger tanks get better and better the bigger they are. The mass of the tanks is mostly a function of it's surface area, growing with n^2, while the fuel stored grows by n^3.

And the SLS tank is pretty darned big indeed, with a very large diameter.

Re: Artemis I Launch Attempt Scrubbed

#89

Post by endymi0n »

theteapot wrote: post #85
endymi0n wrote: post #81

Earlier quoted context omitted.

That‘s exactly what I mean. In their newest plan, they don’t. Someone else does.

Who? They're all on the same team, team USA! Or are you implying the glacial pace will inevitably mean China gets there first?

So even if it was this easy and logical, the only logical consequence would be scrapping SLS right now.

Artemis 3 isn‘t just depending on one, but two super heavy launchers that haven‘t even left the ground yet.

And if you put Starship in the critical path, why would you spend billions to introduce another bottleneck that‘s literally just duplicating Starship‘s ground to orbit capability?

If NASA agenda really only was getting the USA to the moon, the only rational choice would be doubling down on Starship all the way.

Re: Artemis I Launch Attempt Scrubbed

#90

Post by wumpus »

mabbo wrote: post #88
adastra22 wrote: post #65

Earlier quoted context omitted.

> That buys you a lot more cargo capacity for the same sized rocket. I think you mean the same mass rocket, because hydrogen is not dense, which factors into the tradeoffs (more structural mass to contain it).

An excellent point. Fortunately bigger tanks get better and better the bigger they are. The mass of the tanks is mostly a function of it's surface area, growing with n^2, while the fuel stored grows by n^3. And the SLS tank is pretty darned big indeed, with a very large diameter.

Big tanks are a big part of why SLS is financially inefficient.
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