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 hypergolic propellant is a rocket propellant combination used in a rocket engine,whose components spontaneously ignite when they come into contact with each other.
The Centaur is a family of rocket propelled upper stages 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 is being 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.
The expander cycle is a power cycle of a bipropellant rocket engine. In this cycle,the fuel is used to cool the engine's combustion chamber,picking up heat and changing phase. The now heated and gaseous fuel then powers the turbine that drives the engine's fuel and oxidizer pumps before being injected into the combustion chamber and burned.
Gemini 1 was the first mission in NASA's Gemini program. An uncrewed test flight of the Gemini spacecraft,its main objectives were to test the structural integrity of the new spacecraft and modified Titan II launch vehicle. It was also the first test of the new tracking and communication systems for the Gemini program and provided training for the ground support crews for the first crewed missions.
Gemini 2 was the second spaceflight of the American human spaceflight program Project Gemini,and was launched and recovered on January 19,1965. Gemini 2,like Gemini 1,was an uncrewed mission intended as a test flight of the Gemini spacecraft. Unlike Gemini 1,which was placed into orbit,Gemini 2 made a suborbital flight,primarily intended to test the spacecraft's heat shield. It was launched on a Titan II GLV rocket. The spacecraft used for the Gemini 2 mission was later refurbished into the Gemini B configuration,and was subsequently launched on another suborbital flight,along with OPS 0855,as a test for the US Air Force Manned Orbital Laboratory. Gemini spacecraft no. 2 was the first craft to make more than one spaceflight since the X-15,and the only one until Space Shuttle Columbia flew its second mission in 1981;it would also be the only space capsule to be reused until Crew Dragon Endeavour was launched a second time in 2021.
A liquid-propellant rocket or liquid rocket utilizes a rocket engine that uses liquid propellants. Gaseous propellants may also be used but are not common because of their low density and difficulty with common pumping methods. Liquids are desirable because they have a reasonably high density and high specific impulse (Isp). This allows the volume of the propellant tanks to be relatively low. The rocket propellants are usually pumped into the combustion chamber with a lightweight centrifugal turbopump,although some aerospace companies have found ways to use electric pumps with batteries,allowing the propellants to be kept under low pressure. This permits the use of low-mass propellant tanks that do not need to resist the high pressures needed to store significant amounts of gasses,resulting in a low mass ratio for the rocket.
Pogo oscillation is a self-excited vibration in liquid-propellant rocket engines caused by combustion instability. The unstable combustion results in variations of engine thrust,causing variations of acceleration on the vehicle's flexible structure,which in turn cause variations in propellant pressure and flow rate,closing the self-excitation cycle. The name is a metaphor comparing the longitudinal vibration to the bouncing of a pogo stick. Pogo oscillation places stress on the frame of the vehicle,which in severe cases can be dangerous.
Aerozine 50 is a 50:50 mix by weight of hydrazine and unsymmetrical dimethylhydrazine (UDMH),originally developed in the late 1950s by Aerojet General Corporation as a storable,high-energy,hypergolic fuel for the Titan II ICBM rocket engines. Aerozine continues in wide use as a rocket fuel,typically with dinitrogen tetroxide as the oxidizer,with which it is hypergolic. Aerozine 50 is more stable than hydrazine alone,and has a higher density and boiling point than UDMH alone.
The Aerojet Rocketdyne RS-25,also known as the Space Shuttle Main Engine (SSME),is a liquid-fuel cryogenic rocket engine that was used on NASA's Space Shuttle and is currently used on the Space Launch System (SLS).
The J-2 is a liquid-fuel cryogenic rocket engine used on NASA's Saturn IB and Saturn V launch vehicles. Built in the U.S. by Rocketdyne,the J-2 burned cryogenic liquid hydrogen (LH2) and liquid oxygen (LOX) propellants,with each engine producing 1,033.1 kN (232,250 lbf) of thrust in vacuum. The engine's preliminary design dates back to recommendations of the 1959 Silverstein Committee. Rocketdyne won approval to develop the J-2 in June 1960 and the first flight,AS-201,occurred on 26 February 1966. The J-2 underwent several minor upgrades over its operational history to improve the engine's performance,with two major upgrade programs,the de Laval nozzle-type J-2S and aerospike-type J-2T,which were cancelled after the conclusion of the Apollo program.
The Rocketdyne H-1 was a 205,000 lbf (910 kN) thrust liquid-propellant rocket engine burning LOX and RP-1. The H-1 was developed for use in the S-I and S-IB first stages of the Saturn I and Saturn IB rockets,respectively,where it was used in clusters of eight engines. After the Apollo program,surplus H-1 engines were rebranded and reworked as the Rocketdyne RS-27 engine with first usage on the Delta 2000 series in 1974. The RS-27 variant is also used on the Delta II and Delta III.
The Titan II was an intercontinental ballistic missile (ICBM) developed by the Glenn L. Martin Company from the earlier Titan I missile. Titan II was originally designed and used as an ICBM,but was later adapted as a medium-lift space launch vehicle to carry payloads to Earth orbit for the United States Air Force (USAF),National Aeronautics and Space Administration (NASA) and National Oceanic and Atmospheric Administration (NOAA). Those payloads included the USAF Defense Meteorological Satellite Program (DMSP),NOAA weather satellites,and NASA's Gemini crewed space capsules. The modified Titan II SLVs were launched from Vandenberg Air Force Base,California,up until 2003.
Titan IIIB was the collective name for a number of derivatives of the Titan II ICBM and Titan III launch vehicle,modified by the addition of an Agena upper stage. It consisted of four separate rockets. The Titan 23B was a basic Titan II with an Agena upper stage,and the Titan 24B was the same concept,but using the slightly enlarged Titan IIIM rocket as the base. The Titan 33B was a Titan 23B with the Agena enclosed in an enlarged fairing,in order to allow larger payloads to be launched. The final member of the Titan IIIB family was the Titan 34B which was a Titan 24B with the larger fairing used on the Titan 33B.
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.
The staged combustion cycle is a power cycle of a bipropellant rocket engine. In the staged combustion cycle,propellant flows through multiple combustion chambers,and is thus combusted in stages. The main advantage relative to other rocket engine power cycles is high fuel efficiency,measured through specific impulse,while its main disadvantage is engineering complexity.
The pressure-fed engine is a class of rocket engine designs. A separate gas supply,usually helium,pressurizes the propellant tanks to force fuel and oxidizer to the combustion chamber. To maintain adequate flow,the tank pressures must exceed the combustion chamber pressure.
The Aerojet M-1 was the largest and most powerful liquid-hydrogen-fueled liquid-fuel rocket engine to be designed and component-tested. It was originally developed during the 1950s by the US Air Force. The M-1 offered a baseline thrust of 6.67 MN and an immediate growth target of 8 MN. If built,the M-1 would have been larger and more efficient than the famed F-1 that powered the first stage of the Saturn V rocket to the Moon.
A cryogenic rocket engine is a rocket engine that uses a cryogenic fuel and oxidizer;that is,both its fuel and oxidizer are gases which have been liquefied and are stored at very low temperatures. These highly efficient engines were first flown on the US Atlas-Centaur and were one of the main factors of NASA's success in reaching the Moon by the Saturn V rocket.
The LR87 was an American liquid-propellant rocket engine used on the first stages of Titan intercontinental ballistic missiles and launch vehicles. Composed of twin motors with separate combustion chambers and turbopump machinery,it is considered a single unit and was never flown as a single combustion chamber engine or designed for this. The LR87 first flew in 1959.
