Current Space Launch Vehicles Summary "6_4_2.TXT" (14762 bytes) was created on 09-01-89 SPACE LAUNCH VEHICLES The NASA mixed fleet concept calls for the agency to contract for launch services on expendable launch vehicles, or ELVs, for payloads not assigned to the Space Shuttle. This has encouraged the development of new versions of several flight-proven vehicles. It also has led to the end of a tradition that began with the birth of the agency -- assuming the primary responsibility for the launch of unmanned space vehicles carrying NASA payloads. Except for the planned launch of one Delta and one Atlas/Centaur in 1989, and six Scouts through 1993, NASA has turned ELV launch operations over to the vehicle manufacturers and the U.S. Air Force. However, these actions have not changed the technology that all of these vehicles use to get into space -- rocket power. The expendable launch vehicles have one or more powered stages. The manned Space Shuttle, the key element of the nation's Space Transportation System, or STS, is a unique design and is in a class by itself. Payload weight, destination and purpose determine what vehicle capabilities are required for each mission. A low-weight spacecraft designed to operate in near-Earth orbit might be flown aboard the smallest space vehicle, the Scout. Sending a manned Apollo spacecraft to the Moon required the massive Saturn V. The powerful Titan/Centaur combination carried large and complex unmanned scientific explorers such as the Vikings and Voyagers to examine other planets. Atlas/Agenas sent several spacecraft to impact on the Moon. Atlas/Centaurs and Deltas have launched more than 250 spacecraft for a wide variety of applications that cover the broad range of the national space program. NASA Space Vehicles As of 1989, NASA's fleet of space launch vehicles consists of the manned Space Shuttle and the unmanned Scout small-class rocket. Space Shuttle Today, the Space Shuttle is the only manned vehicle that will continue to be launched by NASA. The Shuttle is currently scheduled to begin the first of 20 missions to lift components of Space Station Freedom into orbit in 1995. On April 12, 1981, the first Space Shuttle vehicle lifted off from Pad A on Launch Complex 39 at the Kennedy Space Center. After a two-day, test-flight mission that verified the craft's ability to function in space, the Orbiter Columbia landed at Edwards Air Force Base in California. The vehicle was piloted by astronauts John Young and Robert Crippen. The STS-1 mission marked the first time that a new space vehicle had been manned on its initial flight. The Space Shuttle consists of a reusable delta-winged spaceplane called the orbiter; two solid-propellant boosters, which are recovered and also reused; and an expendable tank containing liquid propellants for the orbiter's three main engines. The assembled Space Shuttle is approximately 184 feet (56 meters) long, 76 feet (23 meters) high to the tip of the orbiter's vertical tail, and 78 feet (24 meters) wide, measuring across the orbiter's wingtips. Liftoff weight of the Shuttle vehicle is approximately 4,500,000 pounds (2,041,200 kilograms). 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 approximately 7 million pounds (31 million newtons) of thrust at liftoff. As the Space Shuttle reaches an altitude of around 31 miles (50 kilometers), the spent solids detach and parachute into the ocean. Two waiting ships recover them for eventual refurbishment and reuse on later missions. The orbiter and the external tank, still attached to each other, continue toward Earth orbit. When the orbiter's main engines cut off, just before achieving orbit, the external tank is jettisoned, to re-enter the atmosphere and break up over a remote ocean area. Using onboard orbital maneuvering engines, the orbiter with its crew and payload accelerates into orbit. Most operational missions last from two to seven days. When the mission is completed, the orbiter re-enters the atmosphere and returns to Earth, gliding to an unpowered landing. Scout The Scout launch vehicle, which became operational in 1960, has undergone systematic upgrading since 1976. The standard Scout vehicle is a solid-propellant, four-stage booster system, approximately 75 feet (23 meters) in length, with a launch weight of 46,620 pounds (21,147 kilograms) and a liftoff thrust of 132,240 pounds (588,203 newtons). It can boost an average payload of 400 to 450 pounds (181 to 204 kilograms) into low Earth orbit. Improvements in the Scout include an uprated third-stage motor which increases the vehicle's payload capability. It can now place up to 465 pounds (211 kilograms) in low Earth orbit. Through 1988, 112 Scouts have been launched. They have been used to place a variety of U.S. and international payloads into inclined, equatorial and polar orbits, for orbital, probe and re-entry missions. LTV Missiles and Electronics Group currently produces the Scout vehicle for NASA. LTV also provides systems management and support for the NASA Scout launches. Scout launches take place at three locations. The NASA Wallops Flight Facility at Wallops Island, VA, is for flights in an easterly direction; the Western Test Range is for polar flights. The vehicle also launches from the Italian San Marco launch platform off the east coast of Kenya, Africa, for equatorial missions. Manufacturer-Launched Space Vehicles Time-proven launch vehicles formerly purchased and put into space by NASA may now be launched by the vehicle manufacturers. In the future, NASA will contract with either the U.S. Air Force or the individual company to procure both vehicles and launch services. These payload boosters include the Scout (not launched from Cape Canaveral) in the small class of launch vehicle; the Delta (McDonnell Douglas Space Systems Co.) in the medium class; the Atlas/Centaur (General Dynamics Corp.) and the Titan III (Martin Marietta Astronautics Group) in the intermediate class; and the Titan IV (Martin Marietta) in the large class. KSC/NASA will retain oversight responsibilities for those vehicles which carry NASA payloads. Since the launch pads for all these vehicles except the Scout are at Cape Canaveral Air Force Station, the manufacturers will reimburse the U.S. Air Force for the use of these facilities and other launch services provided. At the same time, the companies will continue to launch vehicles for the Air Force. Delta The Delta rocket has been called the workhorse of the space program. Since 1960, NASA has been the responsible agency in the launch of more than 180 scientific, weather, and communications spacecraft, along with some military satellites. These spacecraft include the TIROS, Nimbus, ITOS, LANDSAT, and Westar series, and some 28 scientific Explorers. The Delta II is the newest version of this rocket. The U.S. Air Force and McDonnell Douglas first launched this vehicle from Complex 17 at Cape Canaveral Air Force Station in February 1989, carrying the first of 21 upgraded Navstar Global Positioning Satellites into orbit. NASA relinquished control of this launch area to the Air Force in 1988. Delta commercial launches also take place here. The Delta family of vehicles has been upgraded several times over the years. Currently, the most powerful version is the Delta II, which stands 128 feet (39 meters) tall. Nine Castor IV-A strap-on solid rocket boosters augment its first stage. Six of them ignite at liftoff. The remaining three Castors ignite after the first six burn out. All of them burn for approximately 1 minute. The average first-stage thrust with the main engines and the six solid-propellant boosters is 873,400 pounds (3.9 million newtons). The Delta has liquid-fueled first and second stages and a solid-propellant third stage. For most launches today, the third stage has been replaced by a more powerful Payload Assist Module (PAM) solid-propellant stage attached to the spacecraft. The newest version of the PAM upper stage, the PAM-DII, also has been used on Shuttle launches. It boosts spacecraft from the low Earth orbit achieved by the Shuttle orbiter into higher ones. Many spacecraft, especially communications satellites, operate in a geosynchronous orbit some 22,240 miles (35,792 kilometers) above the equator. The Delta II and the PAM-DII together can can lift some 3,190 pounds (1,447 kilograms) into a highly elliptical orbit for eventual transfer into geosynchronous orbit by a motor built into the payload spacecraft. This is more than double the 1,500 pounds (680 kilograms) that a Delta built in 1980 could manage. Atlas/Centaur The Atlas G/Centaur, or Atlas I, is the latest version of the Atlas/Centaur vehicle that first became operational in 1966. General Dynamics uses the Atlas/Centaur to launch military, commercial, and scientific payloads into space from Launch Complex 36 at Cape Canaveral. The Atlas I is 138 feet (42 meters) high. The Atlas first stage produces 438,000 pounds (1,948,000 newtons) of thrust at liftoff. The Centaur second stage develops 33,000 pounds (146,784 newtons) of thrust in a vacuum. The Atlas I can place a 13,000-pound (5,897-kilogram) payload into low Earth orbit. It can also propel 5,150 pounds (2,336 kilograms) into a geosynchronous transfer orbit, or 3,350 pounds (1,520 kilograms) into an Earth escape trajectory. While launched by NASA, the Atlas/Centaur was the standard vehicle for intermediate payloads. The Centaur was the nation's first high-energy, liquid-hydrogen/liquid-oxygen launch vehicle stage. The Atlas/Centaur was the launch vehicle for Surveyor 1, the first U.S. spacecraft to soft-land on the Moon. Some of the other spacecraft launched by NASA Atlas/Centaurs include the Orbiting Astronomical Observatories; Applications Technology Satellites; the Intelsat IV, IV-A and V series of communications satellites; Mariner Mars orbiters; a Mariner spacecraft which made a flyby of Venus and three of Mercury; a Pioneer spacecraft which accomplished flybys of Jupiter and Saturn; and Pioneers that orbited Venus and plunged through its atmosphere to the surface. Titan Martin Marietta uses a variation of the Titan 34D for its commercial launch services from Cape Canaveral Air Force Station. The company will be launching members of the Titan family of rockets for both NASA and the U.S. Air Force. The most powerful version of these launch vehicles, the Titan IV, will be used at first only for Air Force launches. The Titan III-E/Centaur, first launched in 1974, had an overall height of 160 feet (48.8 meters). Designed to use the best features of three proven rocket propulsion systems, this vehicle gave the United States an extremely powerful and versatile rocket for launching large spacecraft on planetary missions. The Titan III-E/Centaur was the launch vehicle for two Helios spacecraft to the Sun, two Viking spacecraft to Mars, and two Voyager spacecraft to Jupiter, Saturn, Uranus, and Neptune. 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 boosters attached. At liftoff, the two solid rockets provided 2.4 million pounds (10.7 million newtons) of thrust. The Centaur element of this staged rocket produced 30,000 pounds (133,440 newtons) of thrust from two main engines and burned for up to 7-1/2 minutes. This stage could be restarted in space, which allowed more flexibility in launch times. Inactive NASA Launch Vehicles Atlas/Agena The Atlas/Agena was a multipurpose two-stage liquid-propellant rocket. It placed unmanned spacecraft in Earth orbit, or inserted them into the proper trajectories for planetary or deep space probes. Several programs used the versatile Atlas/Agena. They included early Mariner probes to Mars and Venus, Ranger photographic missions to the Moon, the Orbiting Astronomical Observatory, and early Applications Technology Satellites. The Agena upper stage also was 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 most of the lunar surface. The Atlas/Agena D stood about 100.4 feet (30.6 meters) high and developed a total thrust at liftoff of approximately 376,000 pounds (1.67 million newtons). It carried an Orbiting Geophysical Observatory (OGO) for its last launch in 1968. Saturn V 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, lifted off 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, Apollo 8 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 a final lunar exploration flight. For its last mission, on May 14, 1973, it lifted the unmanned Skylab Space Station into Earth orbit, where it was later occupied by three crews for a total period of 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 363 feet (111 meters) tall and developed 7.75 million pounds (34.5 million newtons) of thrust at liftoff. Saturn 1B The Saturn 1B originally launched Apollo lunar spacecraft into Earth orbit to train for manned flights to the Moon. The first launch of a Saturn 1B with an unmanned Apollo spacecraft took place in February 1966. A Saturn 1B launched the first manned Apollo flight, Apollo 7, on October 11, 1968. After the completion of the Apollo program, the Saturn 1B launched three missions to man the Skylab space station in 1973. In 1975, it launched the American crew for the Apollo/Soyuz Test Project, the joint U.S./Soviet Union docking mission. Saturn 1B was 223 feet (68 meters) tall with the Apollo spacecraft atop, and developed 1.6 million pounds (7.1 million newtons) of thrust at liftoff.