FAILURE: Sea Launch - Intelsat 27 - February 1, 2013 (0656UTC)

[Prober]

So this BIM pump cannot be tested before launch since it runs on kerosene only along a running main engine. Isn't this an inherent design flaw?

Earlier was mentioned that it is spun up using a ground sourced fluid and then kerosene takes over before liftoff.

This is a common practice.  RS-68 uses ground supplied GHe before GH2 take over during engine thrust buildup. F-1 used ground supplied RP-1.

couldn't an engine test fire have found this problem?
 

[kevin-rf]

couldn't an engine test fire have found this problem?
 

Not if the damage occurred after the test fire.

[zaitcev]

What I find interesting in this case is the fact that the propulsion unit (RD-171) and the TVS system (BIM) are separate systems.  Therefore, RD-171 could have operated flawlessly whilst the TVS failed completely.  I suppose that I'd always assumed that the entire propulsion system was largely integrated and considered a single assembly but I was obviously wrong.

They are integrated in case of RD-180, where there's no separate pump. Perhaps that's where the assumption comes from.

[360-180]

couldn't an engine test fire have found this problem?
 

Not if the damage occurred after the test fire.

  Energomash is conducting firing tests of the RD-171. The engine is delivered to Yuzhmash to Ukraine. Then BIM is installed on the engine.

[Ben the Space Brit]

couldn't an engine test fire have found this problem?
 

Not if the damage occurred after the test fire.

Energomash is conducting firing tests of the RD-171. The engine is delivered to Yuzhmash to Ukraine. Then BIM is installed on the engine.

I admit to developing a new appreciation of SpaceX's hotfire policy, given the number of things that apparently can go wrong that wouldn't necessarily be detected during engine qualification/acceptance testing.

Of course, I get the impression that Zenit's core is something of an unusual case.  If I understand correctly, in most cases, the engine is more of an integrated assembly with its TVS and other ancillary systems but in the case of Zenit fairly major subsystems are provided by third parties and not integrated into the engine until it is handed over to the vehicle integration company.

[Jim]

I admit to developing a new appreciation of SpaceX's hotfire policy, given the number of things that apparently can go wrong that wouldn't necessarily be detected during engine qualification/acceptance testing.

And it does nothing for the upperstage.  You are coming to a conclusion that is not based on logic.

[Ben the Space Brit]

I admit to developing a new appreciation of SpaceX's hotfire policy, given the number of things that apparently can go wrong that wouldn't necessarily be detected during engine qualification/acceptance testing.

And it does nothing for the upperstage.  You are coming to a conclusion that is not based on logic.

I didn't mention the upper stage.  You are coming to a conclusion that's not based on a reading of my post.

[Jim]

I admit to developing a new appreciation of SpaceX's hotfire policy, given the number of things that apparently can go wrong that wouldn't necessarily be detected during engine qualification/acceptance testing.

And it does nothing for the upperstage.  You are coming to a conclusion that is not based on logic.

I didn't mention the upper stage.  You are coming to a conclusion that's not based on a reading of my post.

hotfire  is not a guarantee of finding issues, much like WDR's.

[Antares]

At some point, though, more tests just spend life.  Flight articles should get enough to prove performance and workmanship and nothing more.  You never know if you've used the last good cycle.

[R7]

pointing the obvious (and speculating): static hotfirings won't reveal the issue if it's root cause is related to the dynamics of actually releasing the vehicle.

The BIM was OK at T-0, was it not, otherwise launch would have been cancelled.

[russianhalo117]

pointing the obvious (and speculating): static hotfirings won't reveal the issue if it's root cause is related to the dynamics of actually releasing the vehicle.

The BIM was OK at T-0, was it not, otherwise launch would have been cancelled.

It was fine until it failed to nominally switch completely over to RP-1 (RG-1) and used up the remaining first stage high-pressure helium gas which is used to spin up and start BIM power generation. This resulted in the gradual deceleration of the BIM turbo-pump and increasing loss of TVC and power generation after liftoff.

[Lee Jay]

pointing the obvious (and speculating): static hotfirings won't reveal the issue if it's root cause is related to the dynamics of actually releasing the vehicle.

The BIM was OK at T-0, was it not, otherwise launch would have been cancelled.

It was fine until it failed to nominally switch completely over to RP-1 (RG-1) and used up the remaining first stage high-pressure helium gas which is used to spin up and start BIM power generation. This resulted in the gradual deceleration of the BIM turbo-pump and increasing loss of TVC and power generation after liftoff.

In essence, that switchover isn't tested before launch commit, correct?  Doesn't that seem like a design flaw?

[R7]

It was fine until it failed to nominally switch completely over to RP-1 (RG-1) and used up the remaining first stage high-pressure helium gas which is used to spin up and start BIM power generation.

What kind of valves (if any) are there between BIM turbine and RP-1 source? The He supply surely has valve but does it close during switch over?

[R7]

I admit to developing a new appreciation of SpaceX's hotfire policy, given the number of things that apparently can go wrong that wouldn't necessarily be detected during engine qualification/acceptance testing.

Perhaps better appreciation is of SpaceX use-fuel-as-hydraulic-fluid policy. Merlin TVC gets pressure directly from TPA, no? Dedicated hydraulic pump that does not exist cannot fail.

[kch]

pointing the obvious (and speculating): static hotfirings won't reveal the issue if it's root cause is related to the dynamics of actually releasing the vehicle.

The BIM was OK at T-0, was it not, otherwise launch would have been cancelled.

It was fine until it failed to nominally switch completely over to RP-1 (RG-1) and used up the remaining first stage high-pressure helium gas which is used to spin up and start BIM power generation. This resulted in the gradual deceleration of the BIM turbo-pump and increasing loss of TVC and power generation after liftoff.

In essence, that switchover isn't tested before launch commit, correct?  Doesn't that seem like a design flaw?

Seems to me it's more of a pre-launch-commit-testing flaw.  If the switchover occurred prior to T-0, and was not successful, the launch could be halted.  "Timing is everything."

[JohnFornaro]

I admit to developing a new appreciation of SpaceX's hotfire policy, given the number of things that apparently can go wrong that wouldn't necessarily be detected during engine qualification/acceptance testing.

And it does nothing for the upperstage.  You are coming to a conclusion that is not based on logic.

I didn't mention the upper stage.  You are coming to a conclusion that's not based on a reading of my post.

hotfire  is not a guarantee of finding issues, much like WDR's.

Not sure of what point Jim is trying to make.  Hotfires, and WDR's serve a purpose, but that purpose is to increase confidence, not to provide a guarantee. 

Having followed the discussion over the last few days, I agree with Ben and am better appreciating SpaceX's approach, thanks to a greater understanding of the launch processes from reading the info on this forum.

[Jim]

And Spacex's approach would not have found Sealaunch's problem.  The point is that pad hotfires are not needed in this day and age.  They are good to valid and qualify a design but not need to verify manufacture.   Something has to be wrong with your processes if you.   Also, Spacex's hotfire may have had a part in their current problem

[owais.usmani]

RSC Energia Pledges Support for Sea Launch:

http://www.sea-launch.com/news-q11350-RSC_Energia_Pledges_Support_for_Sea_Launch.aspx

[owais.usmani]

pointing the obvious (and speculating): static hotfirings won't reveal the issue if it's root cause is related to the dynamics of actually releasing the vehicle.

The BIM was OK at T-0, was it not, otherwise launch would have been cancelled.

It was fine until it failed to nominally switch completely over to RP-1 (RG-1) and used up the remaining first stage high-pressure helium gas which is used to spin up and start BIM power generation. This resulted in the gradual deceleration of the BIM turbo-pump and increasing loss of TVC and power generation after liftoff.

In essence, that switchover isn't tested before launch commit, correct?  Doesn't that seem like a design flaw?

Exactly what I was saying. Since it cannot be tested before launch, absolutely nobody can be sure if its in flight condition at T=0. You'll always be keeping your fingers crossed.

[edkyle99]

pointing the obvious (and speculating): static hotfirings won't reveal the issue if it's root cause is related to the dynamics of actually releasing the vehicle.

The BIM was OK at T-0, was it not, otherwise launch would have been cancelled.

I trying to picture in my mind, just now, this failure mode finally cropping up just after liftoff of the 20th or so Energia/Buran.  Would this have been the Soviet's "o-ring"?

 - Ed Kyle