Ares I
A critical activity of Ares I development was the schedule for the J-2X upper stage engine and the five-segment version of the SRB. Engineers were concerned about thrust oscillation and Orion-Ares I integration. In 2008, Lockheed Martin requested that NASA redesign Ares I in order to end integration risks with the Orion crew capsule. The combined test results from the Ares I-X launch and the Ares I static test firing indicated that thrust oscillation was not a critical issue, according to program engineers.