Space Launch System - Orion
Discussion
Congress wanted them to use existing Shuttle components and being the great boondoggle that SLS is, the swamp gets its way.
Same goes for the RS-25 main engines. Sadly, NASA will be destroying 4 of them on every SLS flight. They're only supposed to have about 16 of them in the first place. These are the ones they took off the Shuttles before they went off to museums, plus some from storage.
They've also contracted Aerojet Rocketdyne to restart the production line & build 6 more for now, at the cost of $1.5 billion. They'll also be working on a simpler, one shot version that'll supposedly be cheaper to make.
Seems a complete false economy to me. They could have used the Aerojet Rocketdyne RS-68 engine that the Delta IV & Delta IV Heavy use now. These are the most powerful hydrogen / oxygen engines ever built and are basically a budget one-shot version of the Shuttle engine anyway. They're not as efficient, but they're simpler and much cheaper to build (around $20m each). Changes included having ablative carbon nozzles, which incidentally is why the Delta IV has a distinctive red exhaust. It's kinda blue on the Shuttle which used the same fuel but had a regeneratively cooled nozzle.
The Delta IV heavy, with 3x RS-68 engines:
The Ares V rocket, which was the SLS' cancelled forerunner, was intended to use 6 of these engines
Same goes for the RS-25 main engines. Sadly, NASA will be destroying 4 of them on every SLS flight. They're only supposed to have about 16 of them in the first place. These are the ones they took off the Shuttles before they went off to museums, plus some from storage.
They've also contracted Aerojet Rocketdyne to restart the production line & build 6 more for now, at the cost of $1.5 billion. They'll also be working on a simpler, one shot version that'll supposedly be cheaper to make.
Seems a complete false economy to me. They could have used the Aerojet Rocketdyne RS-68 engine that the Delta IV & Delta IV Heavy use now. These are the most powerful hydrogen / oxygen engines ever built and are basically a budget one-shot version of the Shuttle engine anyway. They're not as efficient, but they're simpler and much cheaper to build (around $20m each). Changes included having ablative carbon nozzles, which incidentally is why the Delta IV has a distinctive red exhaust. It's kinda blue on the Shuttle which used the same fuel but had a regeneratively cooled nozzle.
The Delta IV heavy, with 3x RS-68 engines:
The Ares V rocket, which was the SLS' cancelled forerunner, was intended to use 6 of these engines
Another article on the options the SLS programme faces, concerning mobile launcher readiness timescales, EUS, Europa Clipper etc. I think this was written before the shortage of SRBs became apparent
https://www.nasaspaceflight.com/2018/04/nasas-dual...
NASA RFI for MLM 2
https://www.fbo.gov/index?s=opportunity&mode=f...
https://www.nasaspaceflight.com/2018/04/nasas-dual...
NASA RFI for MLM 2
https://www.fbo.gov/index?s=opportunity&mode=f...
Starting to look like the first flight is going to slip again
https://www.nasaspaceflight.com/2018/05/schedule-f...
https://www.nasaspaceflight.com/2018/05/schedule-f...
More delay
http://spacenews.com/contamination-found-in-sls-en...
And another few $million literally down the tubes
http://spacenews.com/contamination-found-in-sls-en...
And another few $million literally down the tubes
Edited by MartG on Saturday 19th May 23:33
"That contamination turned out to be paraffin wax, which is used to keep the tubes from crimping while being manufactured but is supposed to be cleaned out before shipment. ."
" keep the tubes from crimping " wtf does that mean? @
Also " the program is instituting new inspections and other changes to its quality assurance plans." so we can say that either..
1. there wasn't any inspection prior to fit
2. if there was an inspection it used a technique, which, if authorised, was insufficiently thorough.
3. they are following the connie mantra; ie if a jobs worth doing right once it's worth doing right twice...
@ note :- in a previous life I was a authorised swagelock'er for aircraft BDR..
" keep the tubes from crimping " wtf does that mean? @
Also " the program is instituting new inspections and other changes to its quality assurance plans." so we can say that either..
1. there wasn't any inspection prior to fit
2. if there was an inspection it used a technique, which, if authorised, was insufficiently thorough.
3. they are following the connie mantra; ie if a jobs worth doing right once it's worth doing right twice...
@ note :- in a previous life I was a authorised swagelock'er for aircraft BDR..
Edited by Kccv23highliftcam on Sunday 20th May 08:50
Kccv23highliftcam said:
"That contamination turned out to be paraffin wax, which is used to keep the tubes from crimping while being manufactured but is supposed to be cleaned out before shipment. ."
" keep the tubes from crimping " wtf does that mean?
Sound like hydroforming, only using liquid paraffin instead of water perhaps. Or more likely they pump LP through it after forming, as a preservative layer for storage." keep the tubes from crimping " wtf does that mean?
Depending on the item being formed, they'll push a solid mandrel up the pipe, which stops it crushing inwards when it's bent to rough shape. Maybe add some pre-forming work in a press too. Then they'll inject high pressure water into it, which forces the metal into the shape of the die it's held in.
https://www.youtube.com/watch?v=llhcATrmsBg
https://www.youtube.com/watch?v=fOkCKOWpUr0
It's also possible to fill a pipe full of water and seal both ends. Then it can we wound around a mandrel to shape. The water won't compress, which protects the metal pipe from crimping inwards as well.
https://www.youtube.com/watch?v=P6LrTAQyvb0
Edited by Beati Dogu on Sunday 20th May 10:38
I can't really understand how it gets to that stage to find contamination. If wax is being used in the manufacture of the pipes, you'd expect thorough cleaning to be carried out before delivery, or for it to be picked up after delivery. To have a project this big, expensive and precise to have stuff assembled to that point and then go "oh hang on there's still wax in these pipes" to the extent it's going to cause delays sounds like incredibly poor QC. Which obviously isn't something you want when you're building rockets.
The wax is there to prevent the tube crimping or kinking when bent; fill up tubes with something deformable but non-compressible and bob's your mother's brother. Sand is/was used in shaping custom exhausts, fill up with sand, plug the ends, heat the tube where the bends need to be to red heat and it becomes bendable by hand and the sand prevents kinks. Wax provides the same service but is more compatible with small bore tubing.
Article about large solid rocket motor production - seems Aerojet may be forced to leave the large ( greater than 1m diameter ) motor business. Implications in the long term for SLS SRBs
http://spacenews.com/in-the-wake-of-northrop-orbit...
http://spacenews.com/in-the-wake-of-northrop-orbit...
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