Artemis I Launch Attempt Scrubbed • Hacker News Board

Re: Artemis I Launch Attempt Scrubbed

#31

Post by DougWebb » Sat, Sep 03, 2022, 5:41 PM UTC

the_third_wave wrote: post #15

I assume this means the SRBs need to be disassembled to replace the sealing between the segments seeing as how these were stacked beginning in January 2021 [1] and the sealing is guaranteed for 12 months. This has already been extended for 7-8 months but if the launch is to be postponed until October or later they're coming up to 2 years: The joints connecting each piece of Space Launch System’s five-segment rocket m…

Yeah, it's not like NASA has ever had a problem ignoring their own procedures when it comes to the seals on these kinds of rockets...

Re: Artemis I Launch Attempt Scrubbed

#32

Post by JumpCrisscross » Sat, Sep 03, 2022, 5:43 PM UTC

tonetheman wrote: post #23

thetinguy wrote: post #17

Earlier quoted context omitted.

Artemis is a federal jobs program.

Military budget for the year was 777B... Give what you said all of the military is a jobs program also.

Size of budget doesn’t determine jobs or not. Artemis exists because Congress didn’t like Constellation’s cancellation. Its Block II configuration underperforms Starship at significantly higher cost, both to develop and to operate, all without anywhere close to the technological progress of even Falcon Heavy. SLS exists first to provide jobs. The military-industrial complex has an obvious first and foremost purpose, and it’s pretty good at it.

Re: Artemis I Launch Attempt Scrubbed

#33

Post by thepasswordis » Sat, Sep 03, 2022, 5:45 PM UTC

At this rate it seems really unlikely to me that the next mission will have humans on it.

Re: Artemis I Launch Attempt Scrubbed

#34

Post by hfgbvhevrt » Sat, Sep 03, 2022, 5:47 PM UTC

madaxe_again wrote: post #25

perihelions wrote: post #13

Likely no next attempt until October, per Eric Berger ( Ars Technica ): - "Hearing a rollback to the VAB of the SLS rocket is likely, but I don't have confirmation. If that happens, it is very likely that Artemis I does not launch before October 17, at the earliest." - "I'm told that Space Launch System program officials will recommend a rollback to the VAB to investigate the hydrogen leak. The Artemis I mission mana…

I have my doubts that it will ever launch - the way things are proceeding, they’ll miss October, push to ‘23, and will then end up with parts and systems ageing out due to wear and duty cycles - the rollback to the VAB alone incurs significant wear. Meanwhile, starship will see its first orbital flight (likely not before a few RUDs) while SLS just grows mould. That said, the whole purpose of SLS was to provide jobs a…

When is that first starship orbital launch again?

Re: Artemis I Launch Attempt Scrubbed

#35

Post by Rebelgecko » Sat, Sep 03, 2022, 5:49 PM UTC

somenameforme wrote: post #20

Rebelgecko wrote: post #7

Earlier quoted context omitted.

The record for the shuttle was 6

Make sure you're comparing apples to apples. Launches are usually scrubbed because of weather. Repeatedly bringing a rocket to the pad on launch day that's ultimately not flight-worthy is different than scrubbing because of higher than nominal cross winds. And this case is particularly spectacular because while it's ostensibly just a test, they are literally using the exact same engines that the Space Shuttle used. N…

Sure, STS-61c had 4 scrubs for mechanical issues. STS-71 had a similar ratio. So 4 mechanical scrubs on a semi mature vehicle

Re: Artemis I Launch Attempt Scrubbed

#36

Post by wolfram74 » Sat, Sep 03, 2022, 5:49 PM UTC

jmyeet wrote: post #24

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.

“Wrong” by what standard? Hydrogen has the highest specific impulse but I’d much harder to work with. We have no better propellant. A lot of other launch vehicles use RP-1, which is basically just kerosene. Lower specific impulse so lower payload capacity but it doesn’t need to be cryogenically stored and cooled with everything that entails. That’s a fine choice for single use rockets but when you get into reusable r…

as you said, RP-1 is probably a better choice for throwaway rockets, which SLS is.

Re: Artemis I Launch Attempt Scrubbed

#37

Post by TT-392 » Sat, Sep 03, 2022, 5:55 PM UTC

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.

It is what their engines use, and they weren't gonna use different engines

Re: Artemis I Launch Attempt Scrubbed

#38

Post by AstralStorm » Sat, Sep 03, 2022, 5:55 PM UTC

jmyeet wrote: post #24

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.

“Wrong” by what standard? Hydrogen has the highest specific impulse but I’d much harder to work with. We have no better propellant. A lot of other launch vehicles use RP-1, which is basically just kerosene. Lower specific impulse so lower payload capacity but it doesn’t need to be cryogenically stored and cooled with everything that entails. That’s a fine choice for single use rockets but when you get into reusable r…

Unfortunately methane being a GHG brings additional important problems. Launching a lot of methane rockets would be really expensive to the environment.

(We need to finally replace SRBs with something cleaner too.)

Re: Artemis I Launch Attempt Scrubbed

#39

Post by melling » Sat, Sep 03, 2022, 5:57 PM UTC

IshKebab wrote: post #29

2OEH8eoCRo0 wrote: post #19

Earlier quoted context omitted.

Dark Star. Good movie.

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.

Re: Artemis I Launch Attempt Scrubbed

#40

Post by DanBC » Sat, Sep 03, 2022, 5:59 PM UTC

AstralStorm wrote: post #38

jmyeet wrote: post #24

Earlier quoted context omitted.

“Wrong” by what standard? Hydrogen has the highest specific impulse but I’d much harder to work with. We have no better propellant. A lot of other launch vehicles use RP-1, which is basically just kerosene. Lower specific impulse so lower payload capacity but it doesn’t need to be cryogenically stored and cooled with everything that entails. That’s a fine choice for single use rockets but when you get into reusable r…

Unfortunately methane being a GHG brings additional important problems. Launching a lot of methane rockets would be really expensive to the environment. (We need to finally replace SRBs with something cleaner too.)

> Launching a lot of methane rockets would be really expensive to the environment.

What does it turn into when burnt? Would there be much unburnt methane leaking into the environment from these rockets and the infrastructure to support these rockets?