Somehow, too much fuel entered the chamber ahead of the oxidizer.
That mishapcoupled with the earlier loss of oxidizer from a unit in one of the other four-nozzle clusters when a valve jammed during rendezvous with Skylableft the ferry .
The oxidizer valve can be used as a throttle to reduce the thrust and the engine can be stopped and started any number of times, a maneuver that is difficult or impossible with .
Email letters, July 24, 2013 It is interesting that N2O4, nitrogen tetroxide, is not listed as a toxic fracking fluid despite being patented in 1974 by Getty Oil Co. Number 3929192 for oil and gas drilling. This powerful oxidizer was a propellant for the Titan ll intercontinental ballistic missile.
July 25, 2013 - The Daily Sentinel