Last week’s flight of SpaceX’s Starship SN11 ended literally with a bang after a successful ascent and trademark “belly flop” descent. Company CEO Elon Musk reported on Twitter yesterday, “Ascent phase, transition to horizontal & control during free fall were good. A (relatively) small CH4 leak led to fire on engine 2 & fried part of avionics, causing hard start attempting landing burn in CH4 turbopump. This is getting fixed 6 ways to Sunday.”
Decoding Musk: CH4 is methane, the “fuel” portion of the propellants used in the Raptor rocket motor; the other is liquid oxygen, which oxidizes the methane. “Hard start” refers to the condition when the rocket motor is ignited with too much propellant, which can lead to RUD, or rapid unscheduled disassembly, in the parlance of our times. Only one Starship has “stuck the landing” so far, though it exploded on the pad shortly after touchdown.
SpaceX has completed Starship SN15 (it is skipping a few numbers here) that is due to roll out to the launch pad in Boca Chica, Texas, this week with a series of “unspecified” modifications. NASA Spaceflight reports that “one of the mostly unspecified modifications involves the engines, which are being aided by an increased test cadence at SpaceX’s McGregor test site. The center is currently constructing two additional vertical Raptor test stands to increase throughput.”