The Atlas H was a stage and a half rocket, using the enhanced Atlas rocket designed for use as the first stage of the Atlas G rocket,[1] which differed from the Atlas H in having a Centaur upper stage. This stage was later reused as the first stage of the Atlas I. In practice, an MSDupper stage was flown on all five launches.[2]
Atlas H could put a LEO Payload of 3,630 kg (8,000 lb). A payload of 2,255 kg (4,971 lb) to a GTO. [3]