Our recent launch to place kerbals in orbit around Mun was forced to abort during ascent. After booster separation main engine throttle up did not occur and the rocket began to succumb to lateral air flow and tip over backwards. Afraid of a possible structural failure that would break up the entire rocket, Commander Bob triggered the LES while almost perpendicular to the craft’s velocity vector and the capsule was spun violently, producing several seconds of 6-8Gs. Both Cmdr Bob and Capt Desson were recovered from the Kerblantic without injuries. The cause of the engine failure will be under investigation