Atlas II

Atlas II

The Atlas II is an American expendable launch vehicle developed and operated by General Dynamics (later Lockheed Martin) as an evolution of the long-running Atlas rocket family. Designed primarily to serve the United States government's medium-to-heavy payload requirements, the Atlas II represented a significant upgrade over its predecessors, offering improved performance and reliability for placing satellites into geostationary transfer orbit and low Earth orbit.

Development and Design

Building on the heritage of the Atlas I, the Atlas II introduced uprated engines, a stretched propellant tank, and higher-pressure fuel systems to boost its lift capability. Like earlier Atlas vehicles, it used a stage-and-a-half main propulsion configuration, in which the booster engines jettison during ascent while the sustainer engine and core structure continue burning. An Centaur upper stage powered by liquid hydrogen and liquid oxygen provided the high-energy injection needed for geostationary missions. Standing 47.54 meters tall with a diameter of 3.04 meters, the vehicle presented a slender, recognizable profile consistent with the Atlas lineage. It is capable of delivering 6,580 kg to low Earth orbit and 2,810 kg to geostationary transfer orbit.

Launch History

Based on our flight record, the Atlas II conducted 10 tracked flights between 1991 and 1998, achieving a perfect success rate across all missions. Launches took place from facilities on the United States Eastern and Western Ranges, with Cape Canaveral Air Force Station serving as the primary site for GTO-bound payloads. This unblemished record reinforced the Atlas family's strong reputation for reliability during a period when the U.S. government was heavily invested in assured access to space.

Customers and Payloads

The two dominant customers in our flight record are the United States Air Force and Lockheed Martin, reflecting the vehicle's core role in supporting national security space programs. Several tracked missions carried UHF Follow-On (UHF F/O) satellites — a series of military communications satellites built to replace aging Fleet Satellite Communications spacecraft and provide ultra-high-frequency communications for U.S. naval and joint forces. Among the notable tracked missions are UHF F/O F4, F5, F6, F7, and F8, as well as a DSCS-3 B10 flight, which delivered a Defense Satellite Communications System spacecraft into orbit. The DSCS-3 series provided wideband communications capacity for U.S. and allied military users worldwide.

Legacy

The Atlas II occupied an important transitional role in American launch history, bridging the gap between the early Cold War-era Atlas designs and the more advanced Atlas IIA and Atlas IIAS variants that followed, which added strap-on solid rocket boosters for even greater performance. Together, these Atlas II-family vehicles formed the backbone of U.S. medium-class government launches through the 1990s, paving the way for the eventual introduction of the Atlas III and ultimately the Atlas V. The Atlas II's perfect tracked record stands as a testament to the maturity and rigor applied to its design and production during this era of American spaceflight.