Titan was a family of United States expendable rockets used between 1959 and 2005. The Titan I and Titan II were part of the US Air Force's intercontinental ballistic missile (ICBM) fleet until 1987. The space launch vehicle versions contributed the majority of the 368 Titan launches, including all the Project Gemini crewed flights of the mid-1960s. Titan vehicles were also used to lift US military payloads as well as civilian agency reconnaissance satellites and to send interplanetary scientific probes throughout the Solar System.
A booster is a rocket used either in the first stage of a multistage launch vehicle or in parallel with longer-burning sustainer rockets to augment the space vehicle's takeoff thrust and payload capability. Boosters are traditionally necessary to launch spacecraft into low Earth orbit, and are especially important for a space vehicle to go beyond Earth orbit. The booster is dropped to fall back to Earth once its fuel is expended, a point known as booster engine cut-off (BECO).
Delta II was an expendable launch system, originally designed and built by McDonnell Douglas, and sometimes known as the Thorad Delta 1. Delta II was part of the Delta rocket family, derived directly from the Delta 3000, and entered service in 1989. There were two main variants, the Delta 6000 and Delta 7000, with the latter also having "Light" and "Heavy" subvariants. During its career, Delta II flew several notable payloads, including 24 Global Positioning System (GPS) Block II satellites, several dozen NASA payloads, and 60 Iridium communication satellites. The rocket flew its final mission, ICESat-2, on 15 September 2018, earning the launch vehicle a streak of 100 successful missions in a row, with the last failure being GPS IIR-1 in 1997. In the late 1990s, Delta II was developed further into the unsuccessful Delta III, which was in turn developed into the more capable and successful Delta IV, though the latter shares little heritage with the original Thor and Delta rockets.
Delta IV was a group of five expendable launch systems in the Delta rocket family introduced in the early 2000s. Originally designed by Boeing's Defense, Space and Security division for the Evolved Expendable Launch Vehicle (EELV) program, the Delta IV became a United Launch Alliance (ULA) product in 2006. The Delta IV was primarily a launch vehicle for United States Air Force (USAF) military payloads, but was also used to launch a number of United States government non-military payloads and a single commercial satellite.
Titan IV was a family of heavy-lift space launch vehicles developed by Martin Marietta and operated by the United States Air Force from 1989 to 2005. Launches were conducted from Cape Canaveral Air Force Station, Florida and Vandenberg Air Force Base, California.
The Titan IIIC was an expendable launch system used by the United States Air Force from 1965 until 1982. It was the first Titan booster to feature large solid rocket motors and was planned to be used as a launcher for the Dyna-Soar, though the spaceplane was cancelled before it could fly. The majority of the launcher's payloads were DoD satellites, for military communications and early warning, though one flight (ATS-6) was performed by NASA. The Titan IIIC was launched exclusively from Cape Canaveral while its sibling, the Titan IIID, was launched only from Vandenberg AFB.
Atlas II was a member of the Atlas family of launch vehicles, which evolved from the successful Atlas missile program of the 1950s. The Atlas II was a direct evolution of the Atlas I, featuring longer first stage tanks, higher-performing engines, and the option for strap-on solid rocket boosters. It was designed to launch payloads into low Earth orbit, geosynchronous transfer orbit or geosynchronous orbit. Sixty-three launches of the Atlas II, IIA and IIAS models were carried out between 1991 and 2004; all sixty-three launches were successes, making the Atlas II a highly reliable space launch system. The Atlas line was continued by the Atlas III, used between 2000 and 2005, and the Atlas V which is still in use.
Delta III was an expendable launch vehicle made by McDonnell Douglas. The vehicle was developed from the highly-successful Delta II to help meet the launch demand of larger satellites. 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 kg (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.
The Scout family of rockets were American launch vehicles designed to place small satellites into orbit around the Earth. The Scout multistage rocket was the first orbital launch vehicle to be entirely composed of solid fuel stages. It was also the only vehicle of that type until the successful launch of the Japanese Lambda 4S in 1970.
The Graphite-Epoxy Motor (GEM) is a family of solid rocket boosters developed in the late 1980s and used since 1990. GEM motors are manufactured with carbon-fibre-reinforced polymer casings and a fuel consisting of HTPB-bound ammonium perchlorate composite propellant. GEM is produced by Northrop Grumman Space Systems. GEM boosters are used on the Atlas V and were previously used on the Delta II, Delta III, and Delta IV launch vehicles. A new variant, the GEM 63XL, flew as part of the Vulcan Centaur launch vehicle on 8 January 2024.
Castor is a family of solid-fuel rocket stages and boosters built by Thiokol and used on a variety of launch vehicles. They were initially developed as the second-stage motor of the Scout rocket. The design was based on the MGM-29 Sergeant, a surface-to-surface missile developed for the United States Army at the Jet Propulsion Laboratory.
Atlas is a family of US missiles and space launch vehicles that originated with the SM-65 Atlas. The Atlas intercontinental ballistic missile (ICBM) program was initiated in the late 1950s under the Convair Division of General Dynamics. Atlas was a liquid propellant rocket burning RP-1 kerosene fuel with liquid oxygen in three engines configured in an unusual "stage-and-a-half" or "parallel staging" design: two outboard booster engines were jettisoned along with supporting structures during ascent, while the center sustainer engine, propellant tanks and other structural elements remained connected through propellant depletion and engine shutdown.
Thor was a US space launch vehicle derived from the PGM-17 Thor intermediate-range ballistic missile. The Thor rocket was the first member of the Delta rocket family of space launch vehicles. The last launch of a direct derivative of the Thor missile occurred in 2018 as the first stage of the final Delta II.
The Delta IV Heavy was an expendable heavy-lift launch vehicle, the largest type of the Delta IV family. It was the world's third highest-capacity launch vehicle in operation at the time of its retirement in 2024, behind NASA's Space Launch System and SpaceX's Falcon Heavy and closely followed by CASC's Long March 5. It was manufactured by United Launch Alliance (ULA) and was first launched in 2004. ULA retired the Delta IV Heavy in 2024. Future ULA launches will use the new Vulcan Centaur rocket. Delta IV's final flight was in 9 April 2024.
The Delta L, Thor-Delta L, or Thrust-Augmented Long Tank Thor-Delta was a US expendable launch system used to launch the Pioneer E and TETR satellites in 1969 (failed) and HEOS satellite in 1972. It was a member of the Delta family of rockets.
The Delta N or Thor-Delta N was an American expendable launch system used for nine orbital launches between 1968 and 1972. It was a member of the Delta family of rockets, and the last Delta to be given an alphabetical designation - subsequent rockets were designated using a four digit numerical code.
The Delta 2000 series was an American expendable launch system which was used to conduct forty-four orbital launches between 1974 and 1981. It was a member of the Delta family of rockets, sometimes called Thorad Delta. Several variants existed, which were differentiated by a four digit numerical code. The Delta 1000, 2000 and 3000 series used surplus NASA Apollo program rockets engines for its first and second stages.
The Delta 3000 series was an American expendable launch system which was used to conduct 38 orbital launches between 1975 and 1989. It was a member of the Delta family of rockets. Several variants existed, which were differentiated by a four digit numerical code.
The Star is a family of US solid-propellant rocket motors originally developed by Thiokol and used by many space propulsion and launch vehicle stages. They are used almost exclusively as an upper stage, often as an apogee kick motor.
