Debut firing of NASA's Space Launch System core stage cut short following 'Major Component Failure' The Moon moved a little further from NASA over the weekend as the first firing of the Space Launch System's core stage came to an abrupt halt after only 67.2 seconds. The firing, on 16 January, was the culmination of NASA's Green Run efforts that have seen the Boeing-led core stage erected on the B-2 test stand at Stennis …
Does anybody know how much of each engine was replaced after each Shuttle launch?
I've never seen anything describing what was done to prepare the engines for their next launch, but a quick search dug up the informatjon that they had a complete tear-down and rebuild after 5 flights, but only visual inspections after each flight: the engines seems to have had a fairly complete automatic checkout system built into them, which runs before each firing.
I wonder how much of this stuff has been left off the RS-25 (SLS) version of these engines as part of converting the design to single flight usage.
Unknown, but the point I was trying to make is that RS-25 "reusable" is more like a high-strung race engine. Reusable, yes, but stripped down (and inspected and refurbished) after each event. While SpaceX "reusable" is more like a road car engine: open the hood, check for leaks, change the oil, top off the fuel tanks and launch it again.
<insert Ferrari joke here>
There is no need to be suspicious. NASA has to publish how much they are paying for what for. The bad news is some activities get lumped together and we only see the total cost. The legacy Space Shuttle Main Engines are RS-25Ds. Much of the tooling and equipment to manufacture these has gone. The contract to upgrade the design to Minimal Change Expendable SSME (RS-25E) with the option to order 6 was $1.16B. This includes factory space, manufacturing equipment, tooling, test equipment and the staff to operate it all. The contract was later changed to include delivery of 6x RS-25E for a total of $1.5B.
Congress clearly thought designing rocket engine variants was a vote-gaining way to burn taxpayers' money so the contract was upgraded again to include design of the Low Cost Manufacture Expendable SSME (RS-25F) and delivery of a total of 18 new engines (any mix of RS-25E + RS-25F) for an additional $1.79B.
Finally we have a total cost of $3.5B for all the above and assembly and test of one RS-25D from left over parts and collection and storage of the other 15 RS-25Ds. From this we can infer using legacy RS-25Ds costs about $13M each and RS-25E costs about $56M each. Presumably an RS-25F costs less than an RS-25E.
The clear take-away from this is that congress will need find additional uses for the RS-25 series so the hefty NRE expenditure can be justified by dividing it by a larger number of engines. Clearly RS-25 should be used on the upper stage which would require a re-design for lighting the engine without ground support equipment and optimisation for use in vacuum. With a little effort I am sure the design and delivery of 10x RS-25Vs can cost at least $2B.
"Clearly RS-25 should be used on the upper stage which would require a re-design for lighting the engine without ground support equipment and optimisation for use in vacuum."
But why would they if they have the perfectly good and flight proven RL-10 on the shelf. I don't think there's any upper stage that would benefit from the massive grunt of a vacuum RS-25. Plus the RS-25 design doesn't really lend itself to being an upper stage engine. Redesign would have to be so radical that it might as well be a completely new engine. And if you go that way, why not design a completely new engine, optimized for todays manufacturing methods.
Sad because, while I question the politics behind the SLS and wish the money could be used for better science based space missions, I'm still a space nerd and I wish all space missions well.
Not unexpected because this is the SLS history - overspend, deliver late, and under perform.
No pints for you.
I'm with you on your sentiments about all space travel. Still I believe that it is well beyond obvious that
the SpaceX way is the future of manned space travel for at least the next couple of decades. I just wish
there were some way to get congress (lost cause I fear) and NASA to act on this. I haven't given up on
Bezos Origin yet but I would like to see some real progress, as in orbital payloads and first stage landings
from them.
"a delay now seems inevitable unless engineers decide that the truncated firing provided enough data to proceed"
According to NASA they needed a minimum run of 250 sec. to get enough data. Since the firing only lasted about
1/3 of that it looks like another test will be required.
Which may be a bit of a problem.
They have already stacked the two SRBs at the Cape and they can only be left like that for about a year. Apparently if the Senate Launch System was going to fly this year, the core had to leave the test stand by February so it can be spruced up for flight. Unless the problem is something small (and the word 'Major' was used) that can be resolved by simply removing the faulty engine and plugging in another, I suspect it won't fly this year and yet more money will be poured down the SLS's throat as the SRBs are mothballed.
"Unless the problem is something small (and the word 'Major' was used) that can be resolved by simply removing the faulty engine and plugging in another"
Major components can have small failures, so there's still a chance it might be a quick swap and try again.
Except the "quick" part seems to require something like 10 days for an engine swap and a few weeks (hopefully in parallel) to prepare for the retest. This would push things very close to the cut-off date that has to be met for the core to be shipped (assuming all goes well) for final stacking and use before the SRBs need to be reconditioned.
It probably can all be done, but does it make sense to rush things and risk a RUD of what is a very, very expensive launch vehicle to meet some arbitrary deadline that has been set?
"This is why we test" -- not!
This was not a test during the development stage, when any problems could be fixed with a re-design. In this case the development was supposed to be fully completed, so this was a *validation* test.
To contrast with SpaceX (what a contrast!), when Elon rapidly tests one prototype after another to destruction, he's using lessons learned to accelerate the development process. In this case, if any re-design is needed, it will eliminate the possibility of keeping to their schedule. This test was supposed to be a slam-dunk, simply extra insurance before the final product was assembled. It was definitely not supposed to fail, nor are there plans in place to recover from a failure.
In other words, not all tests are created equal, and this one was at a stage when failure was extra costly.
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