Updates SLS Updates

[4throck]

Big disappointment for me. Was expecting better from flown engines and an almost flight ready vehicle.
It's a repeat of the Boeing Starliner unexpected troubles...

 

[N_Molson]

So a successful ~250 seconds burn was the main criteria to validate the test. The way things are, that criteria has not been met and the program can't move on to the next step. Likely the 2024 timeline is compromised, as it will probably take a year to be ready for another test (almost similar to a launch campaign). I guess this will require decisions at the highest level. We know how politics currently are in the US, and SLS is probably not on top of the "high priority stuff" right now, there's the CoVid to deal with and Biden isn't even formally president yet (we're right in the transition week). Let's hope he'll think that a successful all-american lunar landing would be the best way to end his mandate in 2024...

 

[DaveS]

So a successful ~250 seconds burn was the main criteria to validate the test. The way things are, that criteria has not been met and the program can't move on to the next step. Likely the 2024 timeline is compromised, as it will probably take a year to be ready for another test (almost similar to a launch campaign). I guess this will require decisions at the highest level. We know how politics currently are in the US, and SLS is probably not on top of the "high priority stuff" right now, there's the CoVid to deal with and Biden isn't even formally president yet (we're right in the transition week). Let's hope he'll think that a successful all-american lunar landing would be the best way to end his mandate in 2024...

It will not take a year to be ready for another hot fire. The Green Run campaign was comprised of more than just the hot fire, that was Item#8. The reasons for the longer than planned campaign were the worldwide outbreak of CoViD-19 in March which was then followed by a very active Atlantic hurricane season (FYI, that runs from June 1-November 30) which required complete stand-downs for weeks, so no progress when they had hurricanes blowing across the center.

And the President never makes decisions like this, maybe it requires the NASA Administrator, if the Program can't come to a agreement. They'll be ready for another hot fire in February, without the intervention of higher ups.

And as far as launch campaigns are concerned: The EM-1 launch campaign is longer because it is the first. There's no need to repeat all the EM-1 activities for EM-2.

 

[kuddel]

They'll be ready for another hot fire in February, without the intervention of higher ups.

: Fingers crossed :

 

[Urwumpe]

And as far as launch campaigns are concerned: The EM-1 launch campaign is longer because it is the first. There's no need to repeat all the EM-1 activities for EM-2.

Artemis-I will be the first time all those components fly together into space:

• SLS Core
• Boosters
• Upper Stage
• European Service Module
• Orion

Should this mission really go over the full duration, that would be a major miracle, I expect a HUGE anomaly list there.

 

[DaveS]

The upper stage has flight-history as the Delta Cryogenic Second Stage (DCSS). It just has an 18" stretch of its LH2 tank, everything else is bog standard DCSS equipment.

 

[Urwumpe]

The upper stage has flight-history as the Delta Cryogenic Second Stage (DCSS). It just has an 18" stretch of its LH2 tank, everything else is bog standard DCSS equipment.

Thats what they also said about the RS-25. Its a new system, there will be new problems.

 

[N_Molson]

Its a new system, there will be new problems.

This is a truth in all engineering firsts. You can have something working perfectly, duplicate it and strap the both to a common structure, and suddenly the Hell breaks loose (resonance effects, oscillations...), stuff that can be hard or impossible to simulate. Problem is, with stuff such as cryogenic engines, the kind of pressure you play with is so high that you can't really have a lot of margin, simply because materials have their limits (and the engines have to be lightweight)...

 

[Urwumpe]

This is a truth in all engineering firsts. You can have something working perfectly, duplicate it and strap the both to a common structure, and suddenly the Hell breaks loose (resonance effects, oscillations...), stuff that can be hard or impossible to simulate. Problem is, with stuff such as cryogenic engines, the kind of pressure you play with is so high that you can't really have a lot of margin, simply because materials have their limits (and the engines have to be lightweight)...

Even just installing a Opel Manta engine into a Volkswagen Golf GTI (first gen) is complex, despite both being perfectly proven technology. And I don't even mean the religious consequences of this. (Or rotating the engine and gearbox by 90°)

 

[MaxBuzz]

so far nothing is known about the project where it will be necessary to "create SLS like sausages"

 

[Urwumpe]

so far nothing is known about the project where it will be necessary to "create SLS like sausages"

You have no idea. Germans need no reason to make "something-like sausages". It exists, we sausage-fy it.

 

[N_Molson]

so far nothing is known about the project where it will be necessary to "create SLS like sausages"

Build a Death Star ? ?

 

[Thunder Chicken]

So all the effort to get the stage set up in the stand, their just going to call it "close-enough" and send it? Either the problem is so trivial that fixing it for a retest at this point would be relatively simple to do, or it's something that they are going to need to strip things down and fix at great expense.

They also just had a problem with a power and data unit on Apollo 1, but they're just buttoning it up and going to rely on the backup because they'd have to tear the ship apart to replace the card:

NASA takes delivery of completed Orion Artemis I spacecraft

After fears that it might require disassembly, Lockheed Martin has completed work on the Artemis I Orion spacecraft and has formally transferred possession to NASA's Exploration Ground Systems (EGS) team at the Kennedy Space Center in Florida.

newatlas.com

Everything about this rocket screams "sketchy" to me as an engineer. I hope it blows up before they put astronauts on it, because it seems the only way they are going to fix anything.

 

[cannon_gray]

They're telling themselves the program is an important alternate to Starship, when instead SLS, with 1970's technology, ought to be halted and the ongoing funds given to more private orgs that might actually launch something.

 

[Urwumpe]

They're telling themselves the program is an important alternate to Starship, when instead SLS, with 1970's technology, ought to be halted and the ongoing funds given to more private orgs that might actually launch something.

If this is 1970s technology, the flying grain silos would have an even worse dating.... Their engine cycle was first test fired in the 1960s.

Also, it isn't about "Starship or SLS". they are separate programs by separate organisations. The SLS is still in first place a socialist effort to keep the old NASA contractors in business - and their employees.

 

[Pioneer]

If this is 1970s technology, the flying grain silos would have an even worse dating.... Their engine cycle was first test fired in the 1960s.

Also, it isn't about "Starship or SLS". they are separate programs by separate organisations. The SLS is still in first place a socialist effort to keep the old NASA contractors in business - and their employees.

And they've been doing an EXCELLENT job at guaranteeing money and employment! ???

 

[DaveS]

We have our first post-test update: https://blogs.nasa.gov/artemis/2021...ctions-indicate-core-stage-in-good-condition/

"The Space Launch System (SLS) rocket Green Run team has reviewed extensive data and completed preliminary inspections that show the rocket’s hardware is in excellent condition after the Green Run test that ignited all the engines at 5:27 p.m. EST at NASA’s Stennis Space Center near Bay St. Louis, Mississippi. After analyzing initial data, the team determined that the shutdown after firing the engines for 67.2-seconds on Jan.16 was triggered by test parameters that were intentionally conservative to ensure the safety of the core stage during the test.

These preprogrammed parameters are designed specifically for ground testing with the flight hardware that will fly NASA’s Artemis I mission to ensure the core stage’s thrust vector control system safely moves the engines. There is a thrust vector control (TVC) system that gimbals, or pivots, each engine, and there are two actuators that generate the forces to gimbal each engine. The actuators in the TVC system are powered by Core Stage Auxiliary Power Units (CAPU). As planned, the thrust vector control systems gimbaled the engines to simulate how they move to direct thrust during the rocket’s ascent."

 

[GLS]

We have our first post-test update: https://blogs.nasa.gov/artemis/2021...ctions-indicate-core-stage-in-good-condition/

"The Space Launch System (SLS) rocket Green Run team has reviewed extensive data and completed preliminary inspections that show the rocket’s hardware is in excellent condition after the Green Run test that ignited all the engines at 5:27 p.m. EST at NASA’s Stennis Space Center near Bay St. Louis, Mississippi. After analyzing initial data, the team determined that the shutdown after firing the engines for 67.2-seconds on Jan.16 was triggered by test parameters that were intentionally conservative to ensure the safety of the core stage during the test.

These preprogrammed parameters are designed specifically for ground testing with the flight hardware that will fly NASA’s Artemis I mission to ensure the core stage’s thrust vector control system safely moves the engines. There is a thrust vector control (TVC) system that gimbals, or pivots, each engine, and there are two actuators that generate the forces to gimbal each engine. The actuators in the TVC system are powered by Core Stage Auxiliary Power Units (CAPU). As planned, the thrust vector control systems gimbaled the engines to simulate how they move to direct thrust during the rocket’s ascent."

During the test, the functionality of shutting down one CAPU and transferring the power to the remaining CAPUs was successfully demonstrated. This gimballing test event that resulted in shutting down the CAPU was an intentionally stressing case for the system that was intended to exercise the capabilities of the system.

67.2 - 6 = 61.2s
So they do an intentionally stressing case 1.2s into the gimbal test? Why not start slow and get some info, and then towards the end of the test go bananas with the TVC?

Initial data indicate the sensor reading for a major component failure, or MCF, that occurred about 1.5 seconds after engine start was not related to the hot fire shutdown. It involved the loss of one leg of redundancy prior to T-0 in the instrumentation for Engine 4

A sensor as expected.


Did not know that the CAPUs had exhaust... I thought the flow from the turbine would continue to the tank.

 

[Urwumpe]

Some information about the CAPUs:

SLS Green Run test-firing to verify Core Stage design, analysis before first launch - Page 2 of 2 - NASASpaceFlight.com

At T-4 minutes, the hydraulic systems that help operate and steer the engines will begin…

www.nasaspaceflight.com

 

[DaveS]

Post-test media tele-conference scheduled for 5:30 pm EST today, little more than 90 minutes from now:

https://twitter.com/x/status/1351634539022594049