Delta III

Delta III was an expendable launch vehicle made by McDonnell Douglas (later acquired by Boeing). Development was canceled before the vehicle became operational. The vehicle is the third generation of the Delta rocket family, developed from the highly successful Delta II to help meet the launch demand of larger satellites. While the Delta III never had a successful launch, some of the technologies developed were used in its successor, the Delta IV.

The Delta III was the first to use the Delta Cryogenic Second Stage, which was designed by the National Space Development Agency of Japan based on the second stage it developed for the H-IIA rocket and built by Mitsubishi Heavy Industries. Contraves built the fairing and payload adapters based on designs it used on the Ariane 4.

The first Delta III launch was on August 26, 1998. Of its three flights, the first two were failures, and the third, though declared successful, reached the low end of its targeted orbit range and carried only a dummy (inert) payload. The Delta III could deliver up to 3,810 kilograms (8,400 lb) to geostationary transfer orbit, twice the payload of its predecessor, the Delta II. Under the four-digit designation system from earlier Delta rockets, the Delta III is classified as the Delta 8930.

History

Due to the continual size and mass growth of commercial satellites in the late 1980s, McDonnell Douglas realized the need for a higher-performance rocket than even their new Delta II. New satellite bus offerings from Hughes required a launch vehicle with a 4-meter diameter payload faring as well as the ability to send 3.5 tons of payload to a geostationary transfer orbit – neither of which Delta II offered.

Multiple options for evolving the Delta II to support larger payloads were considered in the late 1980s and early 1990s, namely using higher-performing liquid hydrogen/liquid oxygen upper stages.