Tweaked Space Shuttle Main Engine gets ready for final testing
- Reference: 1696435273
- News link: https://www.theregister.co.uk/2023/10/04/space_shuttle_engine_test/
- Source link:
NASA's Artemis uses parts left over from the Space Shuttle program. It is notable for having managed to turn the Space Shuttle Main Engines from marvels of reusability into disposable units to be dumped into the ocean during launch, along with the rest of the core stage.
However, only a finite number of engines are available, and NASA has contracted Aerojet Rocketdyne to restart production of the RS-25 engine.
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The new engines differ from the Space Shuttle originals. Reusability is no longer required, but extra power is. The engines must also be cheaper to produce so a new design is needed. This design must also be certified, hence the testing.
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The first Artemis mission launched in 2022. The next three will also use modified engines from the Space Shuttle program, tweaked to go to 109 percent of their rated level. The new RS-25 engines will go to 111 percent and be tested to 113 percent to gain a margin of operational safety.
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The October 5 test will take the development engine E0525 to 111 percent and run it for 550 seconds. The longest test will be 650 seconds, and crews will also perform a gimbal test to ensure the engine can pivot correctly. Overall, 6,350 seconds of firing is planned for the test series, and should all go well, the green light will be given to produce 24 new RS-25 engines using the new design.
The tests at the Fred Haise Test Stand at NASA's Stennis Space Center are critical if the Artemis program is to progress beyond the fourth flight in its current form. However, the RS-25 is hardly the only Space Shuttle component that will become scarce should NASA keep launching the SLS.
The Solid Rocket Boosters (SRBs) used in the launch are derived from Space Shuttle parts and expended where the Space Shuttle program would recover and reuse them. NASA has enough parts to get through to Artemis 8 but will need to produce new ones for Artemis 9.
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Similarly, the European Service Module (ESM) currently uses a Space Shuttle Orbital Maneuvering System engine for its primary method of propulsion. From ESM-7, it will require something new.
However, it is the RS-25 engine that is most urgent. Assuming, of course, the SLS is still flying in its current form by the time Artemis V eventually rolls around. ®
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[1] https://www.nasa.gov/news-release/start-your-engines-nasa-to-begin-critical-testing-for-future-artemis-missions/
[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=2ZR3ghXF8hhFYpCeBMobusAAAAFI&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0
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[5] https://www.theregister.com/2023/09/08/nasa_sls_cost_concerns/
[6] https://www.theregister.com/2023/09/07/musks_mighty_missile_is_ready/
[7] https://www.theregister.com/2023/08/22/nasa_moon_space_station/
[8] https://www.theregister.com/2023/08/18/nasa_buildings_upgrades/
[9] 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=44ZR3ghXF8hhFYpCeBMobusAAAAFI&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[10] https://whitepapers.theregister.com/
A similar option for HS2?
250kph Intercity express trains are super-expensive
We have museums full of old steam trains
We fit big resistive electrical heaters in the boilers, run form overhead power lines
= cheap high speed locomotives ready in days
Then we decide we can't electrify the entire line and we've run out of old steam locomotives and we need to make it carbon neutral so we invent miniature nuclear reactors to generate the power to run the heaters to make the steam (we then abandon our design and buy the reactors from N. Korea)
Then we decide it's too dangerous to put the reactors on the train.
So we position them every 10miles along the track, the loco connects to power, raises steam, and runs for 10miles until the boiler is cold
Announce massive success in investing billions in clean power, high speed rail and bringing jobs to run down steam locomotive building regions
Re: A similar option for HS2?
Upvoted for inventive cynicism!
Re: A similar option for HS2?
Ah - the government technical advisor finally reveals (him/her)self. We were wondering where you were hiding.
For all the rubbish thrown at him
..at least Musk has been trying to re-use rockets. Meanwhile, over at NASA it's a case that the ocean's simply one big garbage dump.
Re: For all the rubbish thrown at him
NASA is re-using the rockets
The old ones were built for the Space Shuttle, they are now being "re-used" for this
Then when we run out of the old ones we we build new Space shuttle engines for this project (at only 10x the original cost) - the entire project will then be cancelled and the engines can be take out of storage and "re-used" in a future project
"The new RS-25 engines will go to 111 percent and be tested to 113 percent to gain a margin of operational safety."
Speaking as an engineer, I wouldn't call 2% a margin of operational safety, I'd call it crossing your fingers and hoping nothing goes wrong....
"Speaking as an engineer, I wouldn't call 2% a margin of operational safety, I'd call it crossing your fingers and hoping nothing goes wrong...."
Totally agree. And the "2% margin" mindset was what contributed to the Challenger loss - along with many other things. When the rubber o rings (that held back the hot gasses, and eventually failed on the challenger flight) had failed and burned through half their thickness on earlier flights, senior NASA bods interpreted that as proof of a 50% safety margin (ie there was still 50% o ring left). Other people insisted it was actually all the safety margin gone, and more since the o rings shouldn't have any erosion but they were ignored.
But then, if all space craft were built with a genuine 50% margin they'd probably never get off the ground. Space is hard - and risky.
Yeah, NASA are busy building a nitro drag racer, the sort so extreme the engine block doesn't even have cooling because it only runs for 10 seconds. While crowing about how it's "necessary" and "important" to make it super extreme b/c that extra couple %! When they could build a turbo diesel truck that could be used, I dunno, several times?
Also, wasn't there a report that the production COULD NOT be restarted, because literally ALL of the engineers/machinists were gone, and so rather than calling it "restarting" production, it's more like, developing the production from the ground up all over again.
Not quite
The redesign is "design for manufacture", and "design for lifetime".
The methods used for the original RS25 are still known, and there are still plenty of skilled machinists etc who could build them from the original drawings if desired.
The trouble is that it'd be too expensive, even for the pork barrel that is Artemis - there were many custom tools and labour intensive steps. Humans are expensive.
So they're trying to redesign it for modern manufacturing methods that require fewer highly skilled people, instead using highly flexible CAM machines that they already own and can put to other uses afterwards.
Also, the new ones only need to work once. So as well as higher levels of allowable erosion, it doesn't need to be possible to strip them down for inspection and repair.
It's not really 111% relative to "full power"
It's 100% = nominal level of the 1st generation engines.
Rather than re-calibrating everything (and potential confusion) they kept this as 100% so subsequent Shuttle missions ran at >100% even though this was below full power for later version engines
Isn’t it 1.8%?
> The new RS-25 engines will go to 111 percent
Turn it up to 11! Straight out of the "Spinal Tap" school of rock...etry.
Seriously? This the 21st century and the best NASA can do is use shelved technology from the previous century?
Worse still instead of re-using the old technology as was originally intended now they are just going to dump it into the ocean after one use.
I remember when NASA could be considered the paragon of technical and engineering excellence.
But by leasing the engines back from the project they sold them to and that way, it comes under the monthly current budget and not the capital account !
(round of applause)
Ping!
" to be dumped into the ocean during launch, along with the rest of the core stage."
Are you the type of person who picks up any rubbish you seeing while walking on the beach? Well, you may as well stop bothering.
NASA can dump it quicker that you can pick it up.