L A U N C H V E H I C L E S (Overview) --------------------------------------------------------------------- Overcoming the pull of Earth's gravity is the first challenge of any space mission. Whether small and suborbital or large and traveling to another planet, every spacecraft must be carried into space before it can do its job. NASA has a family of launch vehicles--a graduated series of multistage rockets--to accomplish its space programs. A family of launch vehicles was developed because a number of different vehicles were required for missions that ranged from simple to complex. The vehicles are combinations of two or more stages, which burn one after the other, each being discarded when it is no longer needed, so only a small part of the whole vehicle is necessary to propel the spacecraft into the final orbit or space trajectory. When NASA was formed, its launch capability depended upon what was available and most of the vehicles were derived from the military missile program. In time, additional vehicles were developed, using both solid and liquid propellant rockets, specifically to acquire a variety of launch vehicle combinations suited to the expanded space exploration program. NASA owns launch sites at the Eastern and Western Space and Missile Centers (ESMC and WSMC) in Florida and California and the Wallops Flight Facility in Virginia, and has access to the San Marco launch complex off the east coast of Africa owned by Italy. --------------------------------------------------------------------- R E D S T O N E STATUS: Inactive Adapted by NASA from an Army ballistic missile, the Redstone was used to launch Project Mercury suborbital flights from 1960-61. Redstone flew successfully five times after an initial failure. Two unmanned flights and one with the chimpanzee Ham preceded the first U.S. manned spaceflight by Alan B. Shephard, Jr. in May 1961, and Virgil I. Grissom's flight in July 1961. Redstone measured 25 meters (83 ft) in height with capsule and escape tower. It was a single stage launch vehicle using liquid propellant (alcohol and liquid oxygen) and developed 35,380 kg (78,000 lbs) of thrust. M E R C U R Y - A T L A S STATUS: Inactive Mercury-Atlas was a modified Air Force missile. It stood 29 meters (95.3 feet) high with capsule and escape tower. The vehicle was a stage-and-a-half rocket that produced 139,797 kg (308,000 lbs) of thrust, burning RP-1 (kerosene) and liquid oxygen. Mercury-Atlas was first used for John Glenn's orbital flight in 1962. It launched all succeeding Project Mercury orbital flights. G E M I N I - T I T A N STATUS: Inactive Titan, an Air Force ICBM, was modified by NASA as Titan II for Project Gemini (1965-66). Titan was a two-stage rocket, standing 109 ft in height, burning Aerozine-50 and nitrogen tetroxide and produced 430,000 lbs of thrust in the first stage, 100,000 lbs of thrust in the second. A T L A S / A G E N A STATUS: Inactive The Atlas/Agena was a multipurpose two-stage liquid propellant rocket. It was used to place unmanned spacecraft in Earth orbit, or inject them into the proper trajectories for planetary or deep space probes. The programs in which the versatile Atlas/Agena was utilized included early Mariner probes to Mars and Venus, Ranger photographic missions to the Moon, the Orbiting Astronomical Observatory (OAO), and early Applications Technology Satellites (ATS). The Agena upper stage was used as the rendezvous target vehicle for the Gemini spacecraft during this series of two-man missions in 1965-1966. In preparation for the manned lunar landings, Atlas/Agena launched lunar orbiter spacecraft which went into orbit around the Moon and took photographs of possible landing sites. The Atlas/Agena stood 36.6 meters (120 ft) high, and developed a total thrust at liftoff of approximately 1,725,824 newtons (288,000 lbs). It was the last used in 1968 to launch an Orbiting Geophysical Observatory (OGO). S A T U R N I B STATUS: Inactive The Saturn IB was originally used to launch Apollo lunar spacecraft into Earth orbit, to train for manned flights to the Moon. The first launch of a Saturn IB with an unmanned Apollo spacecraft took place in February 1966. A Saturn IB launched the first manned Apollo flight, Apollo 7, on October 11, 1968. After the completion of the Apollo program, the Saturn IB launched three missions to man the Skylab space station in 1973. In 1975 it launched the American crew for the joint U.S./U.S.S.R docking mission. Saturn IB was 69 meters (223 ft) tall with the Apollo Spacecraft and developed 7.1 million newtons (1.6 million lbs) of thrust at liftoff. S A T U R N V STATUS: Inactive The Saturn V, America's most powerful staged rocket, carried out the ambitious task of sending astronauts to the Moon. The first Saturn V vehicle, Apollo 4, was launched on November 9, 1967. Apollo 8, the first manned flight of the Saturn V, was also the first manned flight to the Moon; launched in December 1968, it orbited the Moon but did not land. Apollo 11, launched on a Saturn V on July 16, 1969, achieved the first lunar landing. Saturn V began its last manned mission on December 7, 1972, when it sent Apollo 17 on the final lunar exploration flight. It was last used on May 14, 1973, when it lifted the unmanned Skylab space station into Earth orbit, where it was occupied by three crews for 171 days. All three stages of the Saturn V used liquid oxygen as the oxidizer. The first stage burned kerosene with the oxygen, while the fuel for the two upper stages was liquid hydrogen. Saturn V, with the Apollo spacecraft and its small emergency escape rocket on top, stood 111 meters (363 ft) tall, and developed 34.5 million newtons (7.75 million lbs) of thrust at liftoff. T I T A N I I I - E / C E N T A U R STATUS: Inactive The Titan III-E/Centaur, first launched in 1974, had an overall height of 48.8 meters (160 ft). Designed to use the best features of three proven rocket propulsion systems, this vehicle gave the U.S. an extremely powerful and versatile rocket for launching large spacecraft on planetary missions. The Titan III-E/Centaur was the launch vehicle for two Viking spacecraft to Mars, and two Voyager spacecraft to Jupiter, Saturn, Uranus and Neptune. It also launched two Helios spacecraft toward the Sun. All provided remarkable new information about our solar system. The Vikings and Voyagers produced spectacular color photographs of the planets they explored. The Titan III-E booster was a two-stage liquid-fueled rocket with two large solid-propellant rockets attached. At liftoff, the solid rockets provided 10.7 million newtons (2.4 million lbs) of thrust. The Centaur stage, still in use today, produces 133,440 newtons (30,000 lbs) of thrust from two main engines, and burns for up to seven and one-half minutes. The Centaur can be restarted several times which allows for more flexibility in launch times. D E L T A STATUS: Active Delta is called the workhorse of the space program. This vehicle has successfully transported over 160 scientific, weather, communications and applications satellites into space. These include the TIROS, Nimbus and ITOS satellites, and many Explorer scientific spacecraft. First launched in May, 1960, the Delta has been continuously upgraded over the years. Today it stands 35.4 meters (116 ft) tall. Its first stage is augmented by nine Caster IV strap-on solid propellant motors, six of which ignite at liftoff and three after the first six burn out 58 seconds into the flight. The average first-stage thrust with the main engines and six solid-propellant motors burning is 3,196,333 newtons (718,000 lbs). Delta has liquid-fueled first and second stages and a solid-propellant third stage. For most launches today, this third stage has been replaced by a Payload Assist Module (PAM) stage attached to the satellite. The new PAM upper stage is also used on Space Shuttle launches. It boosts spacecraft from low Earth orbit achieved by the Shuttle orbiter into higher ones. Many spacecraft, especially communications satellites, operate in a geosynchronous (geostationary) orbit some 35,792 kilometers (22,240 miles) above the equator. With the PAM and a recent change to a more powerful second stage, the Delta can lift some 1,270 kilograms (2,800 lbs) into a highly elliptical orbit, for transfer into geosynchronous orbit by a motor built into the spacecraft. This is almost double the 680 kilograms (1,500 lbs) a Delta could manage ten years ago. A T L A S / C E N T A U R STATUS: Active The Atlas/Centaur is NASA's standard launch vehicle for intermediate payloads. It is used for the launch of Earth orbital, geosynchronous, and interplanetary missions. Centaur was the nation's first high-energy, liquid-hydrogen liquid-oxygen launch vehicle stage. It became operational in 1966 with the launch of Surveyor 1, the first U.S. spacecraft to soft-land on the Moon. Since 1966, both the Atlas booster and the Centaur second stage have undergone many improvements. At present, the combined stages can place over 4,530 kilograms (10,000 lbs) in low-Earth orbit, about 2,020 kilograms (4,453 lbs) in geosynchronous transfer orbit, and over 1,000 kilograms (2,205 lbs) on an interplanetary trajectory. An Atlas Centaur stands 41.9 meters (137.6 ft) tall. At liftoff, the Atlas booster develops over 1.9 million newtons (438,400 lbs) of thrust. The Centaur second stage develops 146,784 newtons (33,000 lbs) of thrust in a vacuum. Spacecraft launched by Atlas/Centaurs include Orbiting Astronomical Observatories; Applications Technology Satellites; Intelsat IV, IV-A and V communications satellites; Mariner Mars orbiters; a Mariner spacecraft which made a fly-by of Venus and three of Mercury; Pioneer spacecraft which accomplished fly-bys of Jupiter and Saturn, and Pioneers that orbited Venus and plunged through its atmosphere to the surface. S C O U T STATUS: Active The Scout launch vehicle, which became operational in 1960, has been undergoing systematic upgrading since 1976. The standard Scout vehicle is a solid-propellant, four stage booster system approximately 23 meters (75 ft) in length with a launch weight of 21,600 kilograms (46,620 lbs) and liftoff thrust of 588,240 newtons (132,240 lbs). Recent improvements include an uprated third-stage motor which increases the Scout's payload capability. It can now place up to 211 kilograms (465 lbs) in low-Earth orbit. The third stage also has been provided with an improved guidance system. Over 100 scouts have been launched to date. They have been used to place a variety of U.S. and international payloads into inclined, equatorial and polar orbits for orbital, probe and reentry missions. S P A C E S H U T T L E STATUS: Active The Space Shuttle consists of a reusable delta-winged spaceplane called the orbiter; two solid-propellant rocket boosters, which are recovered and also reused; and an expendable external tank containing liquid propellants for the orbiter's three main engines. The assembled Space Shuttle is approximately 56 meters (184 ft) long, 23.3 meters (76 ft) high (to tip of orbiter's vertical tail), and 24 meters (78 ft) wide, measured across the orbiter's wingtips. Liftoff weight of the Shuttle vehicle is approximately 2,041,168 kilograms (4,500,000 lbs). At launch, the orbiter's three liquid-fueled engines--drawing propellants from the external tank--and the two solid propellant rocket boosters burn simultaneously. Together, they generate about 28,650,000 newtons (6,400,000 lbs) of thrust at liftoff. As the Space Shuttle reaches an altitude of about 50 kilometers (31 mi), the spent solids are detached and parachuted into the ocean where they are recovered by waiting ships for eventual refurbishment and reuse on later missions. The orbiter and external tank, still attached to each other, continue toward Earth orbit. When the orbiter's main engines cut off, just before orbit is achieved, the external tank is jettisoned, to impact in a remote ocean area. Using onboard orbital maneuvering engines, the orbiter with its crew and payload accelerates into orbit to carry out an operational mission, normally lasting from two to seven days. When the mission is completed, the orbiter reenters the atmosphere, and returns to Earth, gliding to an unpowered landing. Touchdown speed is above 335 kilometers (210 mi) per hour. E X P E N D A B L E L A U N C H V E H I C L E S For the decade of the 1990s and beyond, NASA plans to employ a mixed fleet of launch vehicles in which the Space Shuttle will be complemented by expendable launch vehicles (ELVs). The latter vehicles will not be purchased for NASA operation; NASA will contract for launch services with aerospace companies or procure such services through the Department of Defense. The intent of the plan is to reduce dependence on the Space Shuttle, add flexibility to the space program, and free the Shuttle for manned scientific, Shuttle-unique and important national security missions. A major objective is to accelerate deployment of space science missions backlogged by the Shuttle's temporary removal from service. The number of ELV launches required annually cannot be fixed precisely since it is dependent upon future program approvals. Generally, NASA foresees possible annual need for three to five medium ELVs, one or two each in the intermediate and large classes, and an undetermined number in the small vehicle category. The vehciles available or being developed in these categories are the medium ELV Delta II, built by McDonnell Douglas Corporation; the intermediate Atlas Centaur (General Dynamics Corporation) and Titan III (Martin Marietta Corporation); and the large Titan IV (also Martin Marietta). LTV Aerospace Corporation manufactures the standard small launch vehicle, the Scout. --- NASA Information Summaries, Countdown! NASA Launch Vehicles and Facilities, PMS 018 (KSC), Nov 1986 NASA, The First 25 Years 1958-1983, A Resource For Teachers, EP-182 NASA FACT SHEET, Space Launch Vehicles , KSC 49-80 SPINOFF 1987, Washington Headquarters, 1987-190-760