Depending on the payload, and if the engine failed early (ie navigation predicts it can't hit the target orbit even using all margin), I wonder if navigation might keep all eight engines firing - not do a MECO-1 at all and just hope everything survives the G overload (which could be up to 1.14 x nominal, ie 8/7ths).Reminder: all speculation from first principles.
From the Ars article :QuoteApproximately one minute and 19 seconds into last night’s launch, the Falcon 9 rocket detected an anomaly on one first stage engine. Initial data suggests that one of the rocket’s nine Merlin engines, Engine 1, lost pressure suddenly and an engine shutdown command was issued immediately. We know the engine did not explode, because we continued to receive data from it. Our review indicates that the fairing that protects the engine from aerodynamic loads ruptured due to the engine pressure release, and that none of Falcon 9’s other eight engines were impacted by this event.As designed, the flight computer then recomputed a new ascent profile in real time to ensure Dragon’s entry into orbit for subsequent rendezvous and berthing with the ISS. This was achieved, and there was no effect on Dragon or the cargo resupply mission.Falcon 9 did exactly what it was designed to do. Like the Saturn V, which experienced engine loss on two flights, Falcon 9 is designed to handle an engine out situation and still complete its mission.http://arstechnica.com/science/2012/10/that-smooth-spacex-launch-turns-out-one-of-the-engines-exploded/
Approximately one minute and 19 seconds into last night’s launch, the Falcon 9 rocket detected an anomaly on one first stage engine. Initial data suggests that one of the rocket’s nine Merlin engines, Engine 1, lost pressure suddenly and an engine shutdown command was issued immediately. We know the engine did not explode, because we continued to receive data from it. Our review indicates that the fairing that protects the engine from aerodynamic loads ruptured due to the engine pressure release, and that none of Falcon 9’s other eight engines were impacted by this event.As designed, the flight computer then recomputed a new ascent profile in real time to ensure Dragon’s entry into orbit for subsequent rendezvous and berthing with the ISS. This was achieved, and there was no effect on Dragon or the cargo resupply mission.Falcon 9 did exactly what it was designed to do. Like the Saturn V, which experienced engine loss on two flights, Falcon 9 is designed to handle an engine out situation and still complete its mission.
I wasn't saying the mission was a total failure, just that it could turn out to be a total failure. I'm really relieved the GNC door rumour was wrong, and I hope the Orbcomm one is too. The mission could still turn out to be a total success, though one with a very worrying anomaly. However, even now for all we know it could still end in total failure. Let's not count our Dragons before they hatch.
I did notice another item kinda strange. Was wondering if this was the tank that long ago had "welding issues" ?
The F9 shuts down two engines part way through the boost to keep Gs down, right? Does anybody know how an unplanned shutdown would affect the planned shutdowns?
Any official word on the Orbcomm satellites?
From SpaceX:Quote... Initial data suggests that one of the rocket’s nine Merlin engines, Engine 1, lost pressure suddenly and an engine shutdown command was issued immediately. ... Our review indicates that the fairing that protects the engine from aerodynamic loads ruptured due to the engine pressure release, and that none of Falcon 9’s other eight engines were impacted by this event.
... Initial data suggests that one of the rocket’s nine Merlin engines, Engine 1, lost pressure suddenly and an engine shutdown command was issued immediately. ... Our review indicates that the fairing that protects the engine from aerodynamic loads ruptured due to the engine pressure release, and that none of Falcon 9’s other eight engines were impacted by this event.
"the fairing ruptured...due to the engine pressure release..." so they already know it wasn't aero loads that broke the fairing loose, it was "engine pressure release," which I'm not sure how to interpret...a turbopump self-destructing, or
And if the Orbcomm is in the wrong orbit, does it have enough manoeuvre capability in its own right to get to the correct orbit?
Quote from: Kabloona on 10/08/2012 06:01 pm"the fairing ruptured...due to the engine pressure release..." so they already know it wasn't aero loads that broke the fairing loose, it was "engine pressure release," which I'm not sure how to interpret...a turbopump self-destructing, or "engine pressure release" sounds synonymous to "explosion" to me. Maybe it wasn't a catastrophic explosion, but it definitely went out with a bang.Think about it, if you were SpaceX, would you want to say that one of your engines "exploded"?
Quote from: Kabloona on 10/08/2012 06:01 pm"the fairing ruptured...due to the engine pressure release..." so they already know it wasn't aero loads that broke the fairing loose, it was "engine pressure release," which I'm not sure how to interpret...a turbopump self-destructing, or "engine pressure release" sounds synonymous to "explosion" to me. Maybe it wasn't a catastrophic explosion, but it definitely went out with a bang.
Quote from: MP99 on 10/08/2012 05:20 pmDepending on the payload, and if the engine failed early (ie navigation predicts it can't hit the target orbit even using all margin), I wonder if navigation might keep all eight engines firing - not do a MECO-1 at all and just hope everything survives the G overload (which could be up to 1.14 x nominal, ie 8/7ths).Reminder: all speculation from first principles.The 1.14 G overload would only cause stress (or rather compression) above plan at the cabin end. This might be an issue with tourists but hopefully not for cargos.At the engine end, the force on the frame is what the engines produce. It will be designed for 9 engines. 8 engines firing compared to 7 is still 8/9th of launch compression, even if the acceleration is higher.
Quote from: mmeijeri on 10/08/2012 05:50 pmAny official word on the Orbcomm satellites?And if the Orbcomm is in the wrong orbit, does it have enough manoeuvre capability in its own right to get to the correct orbit?