Delta IV RL10 2-B and Falcon 9 Merlin 1C Flights Recover From Operational Anomaliesby Tommy on 8/10/2012
Photo Credit – Ben Cooper – Launch Photography
The Delta IV upper stage engine on a recent Air Force GPS replacement mission (a Pratt and Whitney RL10 2-B) suffered from slightly low thrust on most if not all its scheduled burns which were recovered by the flight software extending the burns, and the Number 1 engine on last night’s SpaceX space station commercial cargo resupply mission suffered what appears to be a major malfunction requiring the immediate shut down of the engine and a subsequent rapid unscheduled disassembly (RUD in acronym jargon). The event occurred near the supersonic transition and maximum drag in the flight profile, and was therefore difficult to discern from the supersonic shock wave, but you could clearly tell something was terribly wrong from the lack of cheering and serious demeanor of the launch personnel. Theories range from a simple sofware parameter violation or the loss of the corner engine fairing, to complete failure of the turbine and gas generator, and also include more complex speculative scenarios such as buckling of the tank base cascading to outright engine failure. However this dramatic engine failure event with the subsequent destruction of the engine and loss of quite a few large meter sized engine and rocket parts caused no apparent flight profile deviations besides the lengthened burns of the remaining first stage engines, and the remaining flight and mission profile was nominal and successful. It will be interesting to hear what the anomaly investigations report in the coming days, but I anticipate little or no schedule fallout from these events, with an already liberal scheduling of launches in the coming years. This is your armchair rocket scientist reporting.
Update 1 : SpaceX is reporting the debris is the
nozzle imploding engine fairing detaching from engine gas over-pressures after engine shutdown.
Update 2 : There are also questions about the second stage restart necessary to deploy the Orbcomm hitchhiker payload to a higher orbit, and the second stage and Orbcomm satellite may or may not be stranded in low Earth orbit.
Update 3 : from Orbcomm …
Fort Lee, NJ, October 8, 2012 – ORBCOMM Inc. (Nasdaq: ORBC), a global satellite data communications company focused on two-way Machine-to-Machine (M2M) communications, today announced that the first prototype of its second generation of satellites (OG2) was launched on the Cargo Re-Supply Services (CRS-1) mission aboard the SpaceX Falcon 9 launch vehicle from Cape Canaveral, FL, on October 7, 2012 at 8:35 pm EST. The OG2 prototype satellite, flying as a secondary payload on this mission, was separated from the Falcon 9 launch vehicle at approximately 9:00 pm EST. However, due to an anomaly on one of the Falcon 9’s first stage engines, the rocket did not comply with a pre-planned International Space Station (ISS) safety gate to allow it to execute the second burn. For this reason, the OG2 prototype satellite was deployed into an orbit that was lower than intended. ORBCOMM and Sierra Nevada Corporation engineers have been in contact with the satellite and are working to determine if and the extent to which the orbit can be raised to an operational orbit using the satellite’s on-board propulsion system.
This will be the last update on this matter. Clearly the Number 1 engine on CRS-1 failed.
If you care to hear more idiotic commentary on this I can suggest nazispaceflight.com