Delta II Rocket
The Delta II rocket is a family of expendable launch vehicles that were primarily used for satellite launches into various orbits. Developed by Boeing and later operated by United Launch Alliance (ULA), it has a notable history in space exploration and satellite deployment.
History and Development
- Origins: The Delta II evolved from the earlier Thor-Delta rocket family, which itself was derived from the PGM-17 Thor ballistic missile developed by Douglas Aircraft Company.
- First Flight: The first Delta II rocket, known as Delta 178, flew on February 14, 1989, successfully placing the Galaxy 1 communications satellite into orbit.
- Designation System: The Delta II uses a three-digit plus two-letter designation to describe its configuration:
- The first digit indicates the main engine (e.g., 6 for RS-27).
- The second digit indicates the number of strap-on solid rocket boosters.
- The third digit indicates the number of stages.
- The letters indicate the type of payload fairing and additional upper stage options.
Key Features
- Engines: Delta II rockets were powered by either the RS-27A or the Aerojet AJ10-118K engine for the first stage, with solid rocket boosters (Castor 4A or GEM-40).
- Upper Stages: The rocket could be configured with different upper stages like the Delta-K, Delta-PAM, or Star-48 motors.
- Payload Capacity: The Delta II could deliver payloads ranging from 300 to 2,170 kg into geostationary transfer orbit (GTO) depending on the configuration.
Notable Missions
Retirement
The Delta II rocket program was retired after its final flight on September 15, 2018, when it launched the ICESat-2 satellite to measure ice sheet elevation and sea ice thickness. The retirement was due to a combination of factors including the aging of the vehicle and the availability of newer, more cost-effective launch options like Atlas V and Falcon 9.
Sources:
Related Topics: