NASA scrubs Artemis mission yet again because SLS just can't handle the pressure
- Reference: 1662222034
- News link: https://www.theregister.co.uk/2022/09/03/artemis_nasa_scrubbed/
- Source link:
Once again, the countdown was fraught with drama when over-pressure warnings were triggered in the liquid oxygen and hydrogen lines as engineers chilled down the plumbing of the vehicle prior to the loading of chilled fuel. Déjà vu struck as a leak was detected at an 8-inch quick disconnect (QD) point for the hydrogen fueling umbilical line at the base of the rocket (a different QD to the one that leaked during [1]the first attempt earlier this week.)
Engineers paused liquid hydrogen loading to allow the hardware in the area to warm up in the hope that the leak would seal itself. When that failed, engineers had a crack at pressurizing lines to force the balky seal to reseat itself as the countdown clock continued its relentless march toward the launch window.
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Alas, it was all for naught as NASA confirmed the inevitable. There will be no launch of the SLS into the Florida sky today. At least they managed to fill the tanks on the earlier attempt, this time they didn't even get that far before things went wrong.
The [3]#Artemis I mission to the Moon has been postponed. Teams attempted to fix an issue related to a leak in the hardware transferring fuel into the rocket, but were unsuccessful. Join NASA leaders later today for a news conference. Check for updates: [4]https://t.co/6LVDrA1toy [5]pic.twitter.com/LgXnjCy40u — NASA (@NASA) [6]September 3, 2022
Observers would be forgiven for pondering the wisdom of using such a fuel; sure, it gives a bigger bang than the RP-1 favored by the likes of SpaceX's Falcon 9 but, as ably demonstrated by the SLS's woes, has its downsides.
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[8]
The selection of fuel was driven by NASA's decision to use left-over Space Shuttle bits for the SLS - in this case, the RS-25 engines which run on a mixture of liquid oxygen and hydrogen. With more than a decade since the Space Shuttle last launched, dealing with the problematic propellant has presented challenges throughout the dress rehearsal for the SLS launch, and on both the first two launch attempts.
[9]NASA scrubs Artemis SLS Moon rocket launch
[10]NASA identifies landing sites for America's return trip to the Moon
[11]Commercial space station Orbital Reef's design phase passes NASA review
[12]Russian cosmonauts abort ISS spacewalk after suit power fluctuates
It has been said that with Apollo, President John F. Kennedy pulled a bit of the 21st century into the 1960s. It is difficult to avoid the suspicion that with the SLS, NASA has dragged a chunk of the 1970s into the present day. While other rocket operators look to reusability and alternative fuels, the SLS is resolutely expendable and relies on the clearly difficult-to-handle liquid hydrogen.
There remains the potential for a third and final opportunity to launch before the SLS must be hauled back to the Vehicle Assembly Building on September 5. NASA did not confirm if it would take this opportunity or simply admit defeat and roll out the crawler to take the SLS back to the workshop.
The agency will face some awkward questions over the SLS. Excuses such as "but it's a new rocket" will fail to cut the mustard considering the heritage hardware at play and NASA's previous Shuttle experience. The stakes also could not be higher, particularly considering the SpaceX launch pads lurking behind the SLS as a reminder that there is another way. ®
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[1] https://www.theregister.com/2022/08/29/nasa_sls_artemis_scrubbed/
[2] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2YxPOegXtlgD7TZvklq-vDwAAAM0&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0
[3] https://twitter.com/hashtag/Artemis?src=hash&ref_src=twsrc%5Etfw
[4] https://t.co/6LVDrA1toy
[5] https://t.co/LgXnjCy40u
[6] https://twitter.com/NASA/status/1566083321502830594?ref_src=twsrc%5Etfw
[7] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44YxPOegXtlgD7TZvklq-vDwAAAM0&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[8] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33YxPOegXtlgD7TZvklq-vDwAAAM0&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0
[9] https://www.theregister.com/2022/08/29/nasa_sls_artemis_scrubbed/
[10] https://www.theregister.com/2022/08/22/nasa_moon_landing/
[11] https://www.theregister.com/2022/08/23/commercial_space_station_orbital_reef/
[12] https://www.theregister.com/2022/08/19/iss_spacewalk_power/
[13] https://whitepapers.theregister.com/
Recycling
And the reason that the Shuttle main engines used hydrogen/oxygen is that they were based on the Saturn V 2nd stage engines.
Engines in space need to be Hydrogen/Oxygen cos it gets most zoom/blue-whale which is important if you have to lift all the fuel into space.
But you get less total zoom than oxygen/aga-fuel which is why the Shuttle needed the big fireworks, which fortunately caused no problems, and is the reason that everyone else uses oxygen/aga 1st stages (including the Saturn V)
Re: Recycling
Lots of rockets not using LH use boosters as well to take off. There were alternatives Shuttle designs that used a first stage and didn't use boosters.
I don't remember many issues filling the Shuttle main tank - one would think NASA knows what it is doing - in the Saturn V itself two whole stages had to be filled with LH for launch anyway - so if you get issue loading tanks it doesn't really matter where they are.
One reason NASA get on the Moon and far beyond Mars was because it mastered LH technology (Centaur included). Maybe today it could be replaced by something less - but we have to see yet one rocket achieving it.
Re: Recycling
Boosters are a really cheap way of getting extra-zoom, they just occasionally go kaboom.
The Shuttle used oxygen/hydrogen engines purely as a time+cost saving redesign. The statement at the time accepted that it would lead to higher launch costs but didn't mention any risks
I'm as critical as anyone regards SLS, but the ship isn't leaking - the first scrub was a sensor issue, this scrub was on the lines pumping the fuel IN to the rocket.
It is obsolete by design and bordering on a dead duck, but let's be factually accurate.
> this scrub was on the lines pumping the fuel IN to the rocket.
The worrying thing is that this (loading H2) is something that has happened many times before on this hardware. NASA should not be discovering that their equipment is broken at this stage in the preparations.
And the one part that cannot be tested is the SRBs.
the first scrub was a sensor issue
No. The sensor issue was the final nail in the coffin for the launch attempt. There were other issues too.
Hydrogen is HUGE
The main problem with hydrogen is it requires an enormous tank, which gets heavy.
The core up to the bottom of the nose cone of the boosters is the hydrogen tank. That huge tank only holds 317,000lbs of hydrogen.
The tiny rest of the tank from there to the part that necks down is the oxygen tank, which is 1,860,000lbs of oxygen.
If you were flying with methane or RP-1, that tank would be a LOT smaller and more importantly, lighter. That's why the Saturn V used RP-1 in the first stage.
And no, the Saturn V didn't use hydrogen in the first stage, for that reason.
Re: Hydrogen is HUGE
Solid hydrogen is a bit denser than liquid, but then you would need firemen/stokers to shovel the fuel into the engines.
Re: Hydrogen is HUGE
There is a lot on this in "Ignition!: An informal history of liquid rocket propellants" where the multiple trade-offs in terms of specific impulse, storage size, and handling difficulties is covered.
TL;DR H2 & O2 has the highest specific impulse of and sane-to-handle fuel choices, but it is pain to handle.
Gimme a spanner...
... and a ladder! I'll get in and fix it!
Third time's a .... ?
OK, one scrub - that happens.
Twice - unlucky
but after that it's starting to look like incompetence is creeping into the picture.
Re: Third time's a .... ?
Just remember, SLS is a quick & easy build as it's reusing shuttle boosters & engines.
Re: Third time's a .... ?
Well I mean, it is possible that they were using the new Boeing delivery model...
Re: Third time's a .... ?
They should have not trained new engineers using Lego sets...
Re: Third time's a .... ?
Assuming we actually start mining ice on the moon, and split it into hydrogen and oxygen, won't we be using mostly hydrogen/oxygen propulsion engines for further exploration/trips? Seems this sort of engine is necessary or am I missing something?
Re: Third time's a .... ?
Yep, nobody actually cares about the moon. SLS is going to the moon because putting persons on the moon is the simplest achievable goal that the public understands.
Cos wasn't JFK cool and weren't the 60s awesome (if you were a square-jawed white guy fighter pilot)
So we are going to do that again, only this time one of the persons will be an ethnic and one will be a women (although all will be squared-jawed ex-fighter pilots)
Mars has CO2 so we can make methane locally, there is no real advantage in landing on the moon and taking off again to get to Mars
Re: Third time's a .... ?
Man mars mission isn't gonna happen in our life time unless magic travel happens as it takes so long to get there in such a tight space, you'd have to make sure you pick someone who's not gonna go nuts on the way & take out the rest of the crew.
Re: Third time's a .... ?
There's a HUGE reason to go back to the Moon first, and that reason is...
Oops.
If something catastrophic goes ping on the Moon, everyone can evac back to Earth in a lifeboat craft in a couple of days. If you're on Mars, it may take a year or the better part of a decade depending on where the two planets are in orbit. Build on the Moon, figure out how to do it all while relatively close to Earth, figure out your failure points, THEN go to Mars. And who knows, while we're working the problems out perhaps we'll make a quantum leap in transportation technology and Mars becomes an hour-long trip even at the furthest point in orbit ftom Earth.
I really enjoy following these things, but I hope all the campers on Cocoa Beach get a show and don’t go home disappointed. I’ve been there to watch a shuttle go up and it’s a great community but they are going to need to catch their scheduled flights and go back to work soon,
There is going to be HUGE pressure to make the next launch a success.
I do hope the engineers have the balls to stand their ground and scrub if they have reason for it, rather than giving it a go anyway…
Hydrogen Leaks
[1]https://twitter.com/offnom/status/1566028264233107457
[1] https://twitter.com/offnom/status/1566028264233107457
Go Starship go!
Why use hydrogen when Musk has shown methane is far superior? Honestly, just coz they had some old shuttle engines lying around...
It's looking like Starship/Super Heavy will be the first, despite the FAA's attempts to delay it.