https://spacenews.com/green-run-hotfire-test-ends-early/

 

 

MCF! Main Component Failure. Now that doesn't sound good.

To be fair, the disintegration of one of the Raptor engines in the SN8 Starship test flight could also be seen as a main component failure. It is better to get any issues out of the way during tests than during flights. Let's face it, those Rocketdyne F1 engines that powered the Saturn V had their fair share of problems during testing, and yet look how magnificently they worked during the entire Apollo programme.

Yeah, this is not easy work and it comes with lots of potential issues.  Best off to find them on a test rather than on a launch.

1 hour ago, Christopher Low said:

To be fair, the disintegration of one of the Raptor engines in the SN8 Starship test flight could also be seen as a main component failure. It is better to get any issues out of the way during tests than during flights. Let's face it, those Rocketdyne F1 engines that powered the Saturn V had their fair share of problems during testing, and yet look how magnificently they worked during the entire Apollo programme.

 

When was this SN8 engine disintegration? Engines were deliberately shut down, but what disintegration? 

SN8's engines are a proven design of course, whereas this engine failed during development. Why is the question. Random failure, or design flaw?

Nice thing about SN9's engine swap is that Elons boys seem to be able to do it with alacrity. SN10 is built and ready to go too.

Edited January 17, 20215 yr by martin-w

Any news on the nature of the problem, Martin? The engines seemed to be running OK for a minute or so until the shutdown.

14 minutes ago, Christopher Low said:

Any news on the nature of the problem, Martin? The engines seemed to be running OK for a minute or so until the shutdown.

It`s shuttle era RS-25 engines have been tweaked for xtra performance. Some concerns had been voiced about using those engines. 

24 minutes ago, Christopher Low said:

Any news on the nature of the problem, Martin? The engines seemed to be running OK for a minute or so until the shutdown.

 

Not that I've seen. They seem to be keeping the cause to themselves for now. No idea if it was a random failure that could happen to any engine or something more serious.

5 hours ago, martin-w said:

When was this SN8 engine disintegration? Engines were deliberately shut down, but what disintegration? 

The crash at the end was caused by one of the engines shutting down prematurely. Watch the video of the flight and pay attention to the colour of the flame just before it lands. It turns a very distinct green colour which indicates something isn't burning correctly.

7 hours ago, Christopher Low said:

To be fair, the disintegration of one of the Raptor engines in the SN8 Starship test flight could also be seen as a main component failure. It is better to get any issues out of the way during tests than during flights. Let's face it, those Rocketdyne F1 engines that powered the Saturn V had their fair share of problems during testing, and yet look how magnificently they worked during the entire Apollo programme.

The difference between this and SpaceX's failures is how fast SpaceX will learn and respond vs NASA. This failure likely means the SLS doesn't fly this year at all. Meanwhile SpaceX already has several more Starships under construction incorporating the lessons from the previous ones.

31 minutes ago, goates said:

The crash at the end was caused by one of the engines shutting down prematurely. Watch the video of the flight and pay attention to the colour of the flame just before it lands. It turns a very distinct green colour which indicates something isn't burning correctly.

 

Yes but that wasn't an engine failure. It was a loss of pressure in a header tank. Space X have a short term remedy in mind, they are going to use helium. No long term solution yet. So yes, nothing to do with an engine fault. 

 

Engine rich combustion caused the  flame. That generated too much heat and alloys melting caused the green flame.

Edited January 17, 20215 yr by martin-w

There is speculation that this failure may have just been a software issue.

I stand corrected. I remember someone explaining the green flame during the final seconds of SN8's descent, and they implied that the engine was literally tearing itself apart from the inside. However, that was probably a consequence of the other problem, rather than an issue with the Raptor engine itself.

As for the SLS, let's hope that it is just a software issue. I know that NASA take considerably longer to get anywhere than SpaceX, but I still want to see that big booster rise off the launch pad one day

Edited January 18, 20215 yr by Christopher Low

2 hours ago, Christopher Low said:

As for the SLS, let's hope that it is just a software issue. I know that NASA take considerably longer to get anywhere than SpaceX, but I still want to see that big booster rise off the launch pad one day

My expectation will be that like Buran, there will be one launch, and that's it.

Cheers!

6 hours ago, Christopher Low said:

I stand corrected. I remember someone explaining the green flame during the final seconds of SN8's descent, and they implied that the engine was literally tearing itself apart from the inside.

 

I think I recall that at the time too. Think it was just the commentator speculating. Anyway, As I say, SpaceX have a fix in mind for the LOX header tank loss of pressure issue, at least for now. A permanent fix will be at a later date. Helium is a good enough measure to enable testing to continue. 

As for SLS, apparently one of the engines being tested was twenty years old, and previously used on the shuttle. 😀