The Latest Progress Failure

The report has been released:

Members of the commission established that the most probable cause of the accident had been the disintegration of the oxidizer tank of the third stage as a result of the failure of the 11D55 engine, following the fire and disintegration of its oxidizer pump, Roskosmos said. The fire in the pump and its disintegration could be triggered by a possible injection of the foreign particles into the pump’s cavity or by violations during the assembly of the 11D55 engine, such as a wrong clearance between the pump’s shaft and its attachment sleeve, floating rings and impellers, leading to a possible loss of balance and vibration of the rotor.

Sounds like they still have serious QA issues, either in manufacture or processing. And it’s the same third stage that crew uses.

[Update a few minutes later]

Related: Bob Zimmerman writes (among other things, in a general analysis of the world launch industry) that 2016 was the worst year for the Russian launch industry in decades.

12 thoughts on “The Latest Progress Failure”

  1. Who was it that had the idea of using an internal combustion engine to drive piston pumps rather than using a turbopump, was it XCOR? That idea is looking better and better all the time.

        1. Turbopumps still totally blow away internal combustion engines for power/mass, unless you’re looking at a very small pump.

          1. For existing off-the-shelf piston engines I agree. But what about a two-stroke dragster-style engine? Solid engine block, cryogenic propellant cooling so there are no hot parts, alloys run at the peak of their strength-temperature curves, etc. Connect each power piston on the same arm as a pump piston to reduce crankshaft forces. It might be surprisingly workable.

          2. The tradeoff is a better power/mass for turbopumps versus simplicity for piston engines. Turbopumps have to be built to extremely tight tolerances, have to operate at very high RPM, and at very high temperatures. An internal combustion engine can run over a wider range of speeds (allowing deep throttling), and can operate at lower temperatures and wider tolerances.

            You might end up with a slightly lower effective ISP, but have a much more reliable rocket, possibly with a lower cost.

          3. You could just do away with all the moving parts and blast the propellant to high velocity with the exhaust of a smaller rocket engine, then recover the velocity as pressure. I’ve done lots of math on it and it should work.

      1. Apples and oranges. IVF is to electrically power the upper stage and eliminate hydrazine. Ed is talking turbopump replacement for the engines.

        1. Well, not quite apples and oranges. If they’re doing IVF anyway then it makes sense to run the turbo replacement with the same LH2 and LOX. If they get their engine working in space for Vulcan, then that engine is a logical starting point for what I’m talking about.

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