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L A U N C H V E H I C L E S
(Overview)
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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.
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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.
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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