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.
The Centaur is a family of rocket propelled upper stages that has been in use since 1962. It is currently produced by U.S. launch service provider United Launch Alliance,with one main active version and one version under development. The 3.05 m (10.0 ft) diameter Common Centaur/Centaur III flies as the upper stage of the Atlas V launch vehicle,and the 5.4 m (18 ft) diameter Centaur V has been developed as the upper stage of ULA's new Vulcan rocket. Centaur was the first rocket stage to use liquid hydrogen (LH2) and liquid oxygen (LOX) propellants,a high-energy combination that is ideal for upper stages but has significant handling difficulties.
Proton is an expendable launch system used for both commercial and Russian government space launches. The first Proton rocket was launched in 1965. Modern versions of the launch system are still in use as of 2023,making it one of the most successful heavy boosters in the history of spaceflight. The components of all Protons are manufactured in the Khrunichev State Research and Production Space Center factory in Moscow and Chemical Automatics Design Bureau in Voronezh,then transported to the Baikonur Cosmodrome,where they are assembled at Site 91 to form the launch vehicle. Following payload integration,the rocket is then brought to the launch pad horizontally by rail,and raised into vertical position for launch.
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.
The Delta rocket family was a versatile range of American rocket-powered expendable launch systems that provided space launch capability in the United States from 1960 to 2024. Japan also launched license-built derivatives from 1975 to 1992. More than 300 Delta rockets were launched with a 95% success rate. The series was phased out in favor of the Vulcan Centaur,with the Delta IV Heavy rocket's last launch occurring on April 9,2024.
Delta IV was a group of five expendable launch systems in the Delta rocket family. It flew 45 missions from 2002 to 2024. 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.
The Saturn I was a rocket designed as the United States' first medium lift launch vehicle for up to 20,000-pound (9,100 kg) low Earth orbit payloads. Its development was taken over from the Advanced Research Projects Agency (ARPA) in 1958 by the newly formed civilian NASA. Its design proved sound and flexible. It was successful in initiating the development of liquid hydrogen-fueled rocket propulsion,launching the Pegasus satellites,and flight verification of the Apollo command and service module launch phase aerodynamics. Ten Saturn I rockets were flown before it was replaced by the heavy lift derivative Saturn IB,which used a larger,higher total impulse second stage and an improved guidance and control system. It also led the way to development of the super-heavy lift Saturn V which carried the first men to landings on the Moon in the Apollo program.
National Security Space Launch (NSSL) is a program of the United States Space Force (USSF) intended to assure access to space for United States Department of Defense and other United States government payloads. The program is managed by the Assured Access to Space Directorate (SSC/AA) of the Space Force's Space Systems Command (SSC),in partnership with the National Reconnaissance Office.
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 as of 2024.
Geosynchronous Satellite Launch Vehicle (GSLV) is a class of expendable launch systems operated by the Indian Space Research Organisation (ISRO). GSLV has been used in fifteen launches since 2001.
United Launch Alliance,LLC (ULA) is an American launch service provider formed in December 2006 as a joint venture between Lockheed Martin Space and Boeing Defense,Space &Security. The company designs,assembles,sells and launches rockets,but the company subcontracts out the production of rocket engines and solid rocket boosters.
The Atlas III was an American orbital launch vehicle,used in the years between 2000 and 2005. It was developed from the highly successful Atlas II rocket and shared many components. It was the first member of the Atlas family since the Atlas A to feature a "normal" staging method,compared to the previous Atlas family members,which were equipped with two jettisonable outboard engines on the first (booster) stage. The Atlas III was developed further to create the Atlas V.
The Atlas I was a US expendable launch system manufactured by General Dynamics in the 1990s to launch a variety of satellites. It was largely a commercial rebrand of the Atlas G,but did feature several electrical and guidance improvements. Atlas I did not feature any major payload capacity improvements over its predecessor but did offer a larger payload fairing option. Eleven launches took place,with three failures.
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 on 9 April 2024.
The Delta 1000 series was an American expendable launch system which was used to conduct eight orbital launches between 1972 and 1975. It was a member of the Delta family of rockets. Several variants existed,differentiated by a four digit numerical code. Delta 1000 was developed by McDonnell Douglas company in 1972.
The Delta Cryogenic Second Stage (DCSS) is a family of cryogenic-fuelled rocket stages used on the Delta III,Delta IV,and on the Space Launch System Block 1 launch vehicles. The DCSS employs a unique two-tank architecture where the cylindrical liquid hydrogen (LH2) tank carries payload launch loads and forms the upper section. An oblate spheroid tank filled with liquid oxygen (LOX) and the engine are suspended from the LH2 tank and covered by the interstage during initial launch.
Vulcan Centaur is a heavy-lift launch vehicle created and operated by United Launch Alliance (ULA). It is a two-stage-to-orbit launch vehicle consisting of the Vulcan first stage and the Centaur second stage. It replaces ULA's Atlas V and Delta IV rockets. It is principally designed for the National Security Space Launch (NSSL) program,which launches satellites for U.S. intelligence agencies and the Defense Department,but ULA believes it will also be able to price missions low enough to attract commercial launches.
During the lifetime of the Space Shuttle,Rockwell International and many other organizations studied various Space Shuttle designs. These involved different ways of increasing cargo and crew capacity,as well as investigating further reusability. A large focus of these designs were related to developing new shuttle boosters and improvements to the central tank,but also looked to expand NASA's ability to launch deep space missions and build modular space stations. Many of these concepts and studies would shape the concepts and programs of the 2000s such as the Constellation,Orbital Space Plane Program,and Artemis program.
