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Thanks for sharing the above. For sure, they are committed to the 9 engine configuration for now. I was reading were this isn't the first time that they've had problems with the #5 engine over-pressurizing. I assume it is the engine in the middle of the pack. It could be some kind of fuel flow/starvation issue at maximum throttle or maybe some kind of exhaust back pressure problem from the surrounding eight. Throttling it back for the time being might be the quickest fix. Just changing out the engine might not help, since they've had problems with this engine in the past.

Some questions come to mind. If it's the center engine, it shouldn't be as critical for control as any of the others. Also, since they only had 1,000 lbs of cargo on-board, and the craft is rated for putting up to 5 tons into orbit, seems they should have had plenty of thrust available to continue with the remaining eight engines; especially if #5 is the center engine.

Do you know if all of these engines are gimbaled? Is #5 an engine critical for flight control?

My hat is off to them! They've certainly accomplished a lot!!

Thanks,

The Falcon 9 has full gimbal control over all engines, including the center engine. And full control over each engine's thrust, including the center one, is deemed critical for mission success.

The actual (fear) thought that my friend has on the over-pressure issue is that a fuel feeder that was designed for test fires has been used in configuring the vehicle for flight, and that the variation in pressure is coming from increased pressure from gravity feed. It would give a slight anomaly readings during ignition sequence which would seem to immediately go away as soon as flight got underway.

It wouldn't affect flight - just those moments from ignition and hold until flight. And the 'fix' is simply adjusting the tolerance parameters for ignition and hold release.

His comment about the design / construction / testing phases has been: Detailed engineering meets real world conditions, and a whole lot of 'rocket science' has been applied to the construction and testing phases - that of changing things on the fly to make the engines work in the real world.

Some questions come to mind. If it's the center engine, it shouldn't be as critical for control as any of the others. Also, since they only had 1,000 lbs of cargo on-board, and the craft is rated for putting up to 5 tons into orbit, seems they should have had plenty of thrust available to continue with the remaining eight engines; especially if #5 is the center engine.

Treating this separately as it is a separate issue. Yes, they could have completed the mission of delivery today by shutting down engine 5 and continuing the mission with the other 8 engines. Yes, that ability would work in full payload conditions, but is outside of the parameters of this test - It is a test flight first, a resupply mission second. The test flight regime required all systems to be nominal throughout the entire mission, including launch.

It is probable that what will happen is that the parameters for the sensor on engine 5 will be expanded as to what is nominal under launch conditions with extensive review of the data from the flight before making it a permanent adjustment.

The least likely exercise is simply changing the engine from the other Falcon 9 rocket on site - or rather was the least likely at the time of the flight meeting - the amount of press out there stating that it was a bad engine might force them to do the engine change.

The plan at this point is to scope out the engine, examine the data, and reset for the Tuesday launch window with no changes to the flight package.