 Yeager was able to complete his flight safely due to the remarkably smooth flight provided by Wyld's system and despite the fact that he had broken several ribs while horse-riding the previous day.In early 1956, following an extensive bidding war, Reaction Motors, Inc. was awarded a contract from the United States Navy for the development of the proposed XLR30 engine to be used to pilot the experimental aircraft known as X-15 and eventually pursue manned spaceflight.After much misadventure, a massive increase in budgetary requirements, and engineering problems related to fuel injectors and the thrust chamber which resulted in the Navy enlisting the assistance of the Rocketdyne Division of North American Aviation, the XLR30 engine project was moved back on track with a new designation of TR-139 to convey the striking changes in design which were required.