The Scout X-2B was an American expendable launch system which was flown during 1963. It was a four-stage rocket, based on the earlier Scout X-2, but with an fourth stage in place of the used on the X-2. It was a member of the Scout family of rockets. The Scout X-2 was an all-solid rocket, with an first stagea Castor 1A second stage, an third stage, and an Altair 2A fourth stage. It made only one flight, which was launched from Launch Complex D at Point Arguello, carrying a P-35 weather satellites, . The launch occurred on 27 September 1963, and failed to achieve orbit.