Posted on 05/18/2012 6:50:06 PM PDT by KevinDavis
Engine #5 seems to have had a high pressure reading. That’s the trouble with so many engines...
Engine 5 abort...chamber pressure high.
Next launch window Tuesday, May 22 at 12:44am Pacific.
*sigh*
If I heard right an over pressure in engine 5......if they go tomorrow I’ll be here.
or engine 5 pressure chamber was high
ya it sucks.. I’ll be here on the 22 too
Yea, I suppose they can run a test on the sensor. If it checks out, then what? Engine change?
i don’t know
I *might* be here on the 22nd. IF I can manage to wake up then. Got an early start for work on that day as well. As it stands, gotta be up and about in 2 hours anyway.
Sounds like a reboot and they try to go tuesday, god speed guys.
oh man!! good luck for today
Too bad they couldn’t shut the one down and launch on the remaining 8. Maybe in future designs...
I always get nervous with engine counts of more than 5. The Soviets (as you might recall) never developed the large-capacity engines (like the Saturn V’s F-1) and relied on multiple smaller engines. Their moon rocket (the N-1) might actually have succeeded IF the first stage didn’t have to rely on the perfect sychronization of something like 22 engines.
To me, more engines = more that can go wrong.Today could be mild proof of that.
Another thing, the one area where you could have extra capacity without too much of a weight penalty would be engine size.
No doubt they'll get it figured out in a timely manner. That's the great thing about private enterprize!
A friend who was working in the design and engine testing phase said that it was a very deliberate choice to go with more engines/smaller engines exactly for the reason of what happened today. The ability to abort the launch AFTER engine start. This is the largest engine they can make that can reliably be shut down after ignition and initial rev up of the engines.
An uncontrolled engine is a constant fear among the designers; the launch vehicle depends upon exact control of all engines throughout the initial launch. If I recall correctly, it's less than a few thousand feet after clearing the tower that the launch vehicle can compensate for engine failures of up to seven of the nine engines and remain in controlled flight.
I didn’t stay up for it because I had a feeling it wasn’t going to happen. To see that the countdown had made it all the way to T-1 second is just frustrating. Oh well. They’ll get another crack at it on the 22nd.
My opinion in regards to engine #5 is that it is a faulty sensor that caused the problem. Hopefully it’ll be easy to change it, test it, and see the Falcon 9 off to LEO.
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,
SPACEX/NASA DISCUSS LAUNCH ABORT OF FALCON 9 ROCKET
http://www.youtube.com/watch?feature=player_embedded&v=nV_JqBOeXMk#!
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.
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.
Thanks for the information on the gimbal control. I was looking everywhere to no avail.
It'll be interesting to learn what they determine the issue to be and the final fix. Certainly real world meets the best engineering has always been a problem. lol
Please keep us posted,
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