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Thread: Space Launch System (SLS)

  1. #211
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    And to save quite some development time, of course....erm never mind.
    With sufficient thrust, water towers fly just fine.

  2. #212
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    "Green Run Update: Engineers Repair Valve for Mid-March Hot Fire Test"

    https://www.spacedaily.com/reports/G..._Test_999.html

    Engineers have successfully repaired a liquid oxygen valve on the Space Launch System rocket's core stage with subsequent checks confirming the valve to be operating properly.

    The team plans to power up the core stage for remaining functional checks later this week before moving forward with final preparations for a hot fire test in mid-March at NASA's Stennis Space Center near Bay St. Louis, Mississippi. NASA anticipates setting a target date for the hot fire next week.

    Last week during checkouts for the second hot fire test, data indicated the valve (a type of valve called a pre-valve) was not working properly.
    I am because we are
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  3. #213
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    I can't wait for they finally realize SLS is a bucket of nails that never flies and it is a waste of time

  4. #214
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    ^^ Agreell

  5. #215
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    Green run (well, walk...) hot fire test attempt 2 in about 6 minutes!
    With sufficient thrust, water towers fly just fine.

  6. #216
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    One engine appears to burn a bit more yellow than the others, and there is a bit of fire above it.
    With sufficient thrust, water towers fly just fine.

  7. #217
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    4 minutes in and continuing, so I guess it's running fine.
    With sufficient thrust, water towers fly just fine.

  8. #218
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    The yellow/orange appears to be a trick of the light; it depends on the camera angle and background. 8 minutes in, all seems well. Cutoff.

    Congrats to the team!
    With sufficient thrust, water towers fly just fine.

  9. #219
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    Quote Originally Posted by Nicolas View Post
    The yellow/orange appears to be a trick of the light; it depends on the camera angle and background. 8 minutes in, all seems well. Cutoff.

    Congrats to the team!
    Yes congratulations, finally.

  10. #220
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    Quote Originally Posted by Nicolas View Post
    The yellow/orange appears to be a trick of the light; it depends on the camera angle and background. 8 minutes in, all seems well. Cutoff.

    Congrats to the team!
    Well, maybe. There was chatter on the loop that something was burning, above the engine. Looked like it to me too.

  11. #221
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    Quote Originally Posted by schlaugh View Post
    Well, maybe. There was chatter on the loop that something was burning, above the engine. Looked like it to me too.
    After the test one guy was indicating that some "stuff", I couldn't understand what, was installed by Boeing and this burning was expected, or burning like went on.

  12. #222
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    Quote Originally Posted by Nicolas View Post
    One engine appears to burn a bit more yellow than the others, and there is a bit of fire above it.
    I suppose you're refering to the fire that I saw too. There were thermal blankets above the engines, and it appears to me that this is where the fire was. Quite some above one of the engines for multiple minutes, and a shortlived smaller fire above another engine. It didn't look like a fire that was being significantly fed, more like the outer coat of the thermal blanket gently burning.

    But that's just what I saw without any detailed understanding of whatever structure exists in those regions, so take this for whatever little it is worth.
    With sufficient thrust, water towers fly just fine.

  13. #223
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    So they have this done, finally, how long before they announce the flight has slipped to 2022?

  14. #224
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    Congrats to a great test of hydrogen engines.

  15. #225
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    Quote Originally Posted by publiusr View Post
    Congrats to a great test of hydrogen engines.
    Yep, good to know the Shuttle Main Engines still work. Too bad these engines, designed to be reusable (where their expense made some sense) will be trashed after one flight.

    "The problem with quotes on the Internet is that it is hard to verify their authenticity." Abraham Lincoln

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  16. #226
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    Quote Originally Posted by publiusr View Post
    Congrats to a great test of hydrogen engines.
    I think that great test was done on march 16, 1977. Yesterday's checkup just showed the old stock isn't broken yet.
    With sufficient thrust, water towers fly just fine.

  17. #227
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    Quote Originally Posted by Nicolas View Post
    I think that great test was done on march 16, 1977. Yesterday's checkup just showed the old stock isn't broken yet.
    As Bernardo Senna on NASAwatch put it: "Great, the Shuttle engines work. Party like it's 1981."

  18. #228
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    Quote Originally Posted by bknight View Post
    After the test one guy was indicating that some "stuff", I couldn't understand what, was installed by Boeing and this burning was expected, or burning like went on.
    Well, after all, the Delta IV is well known for setting itself on fire at launch!
    Cum catapultae proscriptae erunt tum soli proscript catapultas habebunt.

  19. #229
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    Quote Originally Posted by Nicolas View Post
    I think that great test was done on march 16, 1977. Yesterday's checkup just showed the old stock isn't broken yet.
    Don't worry they have enough for I think its four flights? That should pretty much cover all the SLS flights likely to happen.

  20. #230
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    Quote Originally Posted by Trebuchet View Post
    Well, after all, the Delta IV is well known for setting itself on fire at launch!
    I did like the RS-68s. What I really wanted was an Ares V like Energiya-Buran type Shuttle II for modularity. Something like Falcon for strap-ons. Keep the core in orbit. A heads-up ascent for an orbiter-that can have jets where the OMS pods go. Aerobrake disks and orbiter sized hypersonic waveriders that would be released from the 747 orbiter ferry for low speed tests first. Now we are back to capsules. Whee...If SLS stays alive, maybe...
    Last edited by publiusr; 2021-Mar-19 at 07:55 PM.

  21. #231
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    Quote Originally Posted by publiusr View Post
    I did like the RS-68s.
    Ablatively cooled for cost reduction but still manages to cost $20+M/engine, pays the price of hydrogen fuel for performance which it then squanders with a gas-generator combustion cycle, a hydrogen engine with no air-start capability, thrust/weight ratio of less than 50 on a booster engine, thermal issues related to the ablative cooling that prevent clustering (which prevented it from being used on the Ares V, the predecessor to the SLS, to keep this vaguely on-topic)...that RS-68? The engine behind the second least economical medium-heavy launch vehicle to ever fly after the Shuttle (third if the SLS ever gets off the ground), a commercial failure in large part due to its engine technology, now largely famous for the delays it encounters whenever they try to launch it?

    Um...why? Aesthetics?

  22. #232
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    I heard it had much fewer parts. 3D printing, channel wall...lots of things to look at down the road

  23. #233
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    Quote Originally Posted by publiusr View Post
    I heard it had much fewer parts. 3D printing, channel wall...lots of things to look at down the road
    Simplicity is valued when it results in reduced cost and improved reliability. The RS-68 is expensive, and look at recent experience trying to launch the Delta IV Heavy for how the "reliability" part turned out. It's a touchy and finicky launch system, largely due to issues with engine-related systems. And again, as found out when RS-68 was specified as the engine for the Ares V, its ablative nozzles make it a poor fit to large multi-engine vehicles.

    It's already largely obsolete as an expendable hydrogen-burning booster engine, and it has a poor T/W ratio, low specific impulse for a hydrogen engine, and the clustering limitations on top of that. It's not exactly what I'd look for in "the engine of tomorrow".

  24. #234
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    With regard to proposed new NASA administrator he had some fascinating things to say about SLS back when it was being proposed:

    Alongside Texas Senator Kay Bailey Hutchison, in 2010 and 2011, Nelson was a key architect of the SLS rocket. NASA and the White House were wary of tackling this project, as it was well understood that building the rocket through traditional, cost-plus contracting methods would be time-consuming and expensive. The Obama administration wanted to see if private companies, such as United Launch Alliance and SpaceX, could do a better job.

    Nelson relentlessly fought against this and promised that the SLS rocket program would deliver. “This rocket is coming in at the cost of what not only what we estimated in the NASA Authorization act, but less,” Nelson said at the time. “The cost of the rocket over a five- to six-year period in the NASA authorization bill was to be no more than $11.5 billion. This costs $10 billion for the rocket.”

    Later, he went further, saying, "If we can't do a rocket for $11.5 billion, we ought to close up shop."
    https://arstechnica.com/science/2021...administrator/

    So guess a lot of NASA and Boeing people are going to be looking for new jobs? Or some pretzel twisting logic as to why that shouldn't be taken at face value?

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