All Expendable Launch Vehicles use the same basic technology
to get into space – two or more rocket-powered stages, which
fall away when their engine burns are completed. Whatever
a launch vehicle carries above the final discarded stage is considered
the payload.
A payload’s weight, orbital destination and purpose determine
what size launch vehicle is required. A small ELV like Pegasus can
place a low-weight spacecraft into near-Earth orbit, while an expendable
vehicle like the massive Saturn V was required to send manned Apollo
spacecraft to the Moon.
The powerful Titan/Centaur combination carried large and complex robotic scientific
explorers, such as the Vikings and Voyagers, to examine other planets in the
1970s. Among other missions, the Atlas/Agena vehicle sent several spacecraft
to photograph and then impact the Moon. Atlas/Centaur vehicles launched many
of the larger spacecraft into Earth orbit and beyond.
To date, Delta launch vehicles have carried more than 200 NASA scientific, wind
and communications payloads into orbit, or to other planets. NASA used the Athena
I and II vehicles to launch scientific satellites from VAFB, CCAFS and Kodiak
Island. The Pegasus, an Orbital Sciences fleet vehicle, is the only airborne
launch vehicle in the ELV fleet. The Taurus vehicle, also built by Orbital Sciences,
may be used for future NASA launches.
ELV Services Fleet
Atlas/CentaurThe Atlas/Centaur vehicles first became operational
in 1966. Lockheed Martin used the Atlas II and III vehicles to launch
military, commercial and scientific payloads into space from Space
Launch Complex 36 at CCAFS and Space Launch Complex 3E at VAFB. More
than 580 Atlas flights have taken place, including 170 flights with
the Centaur stage added to create the Atlas/Centaur vehicle.
When launched by NASA through 1989, the Atlas/Centaur was
the standard vehicle for intermediate payloads that carried about
8,200 pounds (3,700 kilograms) to Geosynchronous Transfer Orbit (GTO).
The Centaur was the first high-energy, liquid-hydrogen/liquid-oxygen
launch vehicle stage, and it provided the most power for its weight
of any proven stage then in use.
The Atlas/Centaur was the launch vehicle for Surveyor I,
the first U.S. spacecraft to soft-land on the Moon. Other spacecraft
launched by 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
that made a flyby of Venus and three flybys of Mercury; Pioneers,
which accomplished flybys of Jupiter and Saturn; and Pioneers that
orbited Venus and sent probes plunging through its atmosphere to the
surface. Most recently, NASA launched the Tracking Data and Relay
Satellite-J communication satellite Dec. 4, 2002, on an Atlas IIA
from CCAFS.
Lockheed Martin developed the Atlas III launch system that
debuted in 2000. This vehicle can carry more than 8,819 pounds (4,000
kilograms) to geosynchronous transfer orbit. The Atlas V system, the
newest of Lockheed Martin’s fleet, first launched Aug. 21, 2002,
carrying a commercial communications satellite. The AtlasVcan carry
from 8,700 pounds (3,946 kilograms) to 19,100 pounds (8,663 kilograms)
to GTO from Space Launch Complex 41 at CCAFS.
Delta
Delta rockets have been built and launched since 1960. Delta's
origins go back to the Thor intermediate-range ballistic
missile, which was developed in the mid-1950s for the U.S.
Air Force. The Thor, a single-stage, liquid-fueled rocket,
was modified to become the Delta launch vehicle, which later
evolved into the Delta II.
Known as the "workhorse" of the launch industry,
the Delta II comprises a group of expendable rockets that
can be configured as two- or three-stage vehicles and with
three, four or nine strap-on graphite epoxy motors (GEMs)
depending on mission needs.
Delta IV was developed in partnership with the U.S. Air
Force EELV program and is the most advanced family of Delta
rockets. Delta IV blends advanced and proven technology to
launch virtually any size medium-to-heavy class payload to
space.
Pegasus
On April 5, 1990, Orbital began a new era in commercial space
flight when our Pegasus rocket was launched for the first
time from beneath a NASA B-52 carrier aircraft in a mission
that originated from Dryden Flight Research Center in California.
In the decade since its maiden flight, Pegasus has become
the world's standard for affordable and reliable small launch
vehicles. It has conducted 38 missions, launching 78 satellites.
The three-stage Pegasus is used by commercial, government
and international customers to deploy small satellites weighing
up to 1,000 pounds into low-Earth orbit. Pegasus is carried
aloft by our "Stargazer" L-1011 aircraft to approximately
40,000 feet over open ocean, where it is released and then
free-falls in a horizontal position for five seconds before
igniting its first stage rocket motor. With the aerodynamic
lift generated by its unique delta-shaped wing, Pegasus typically
delivers satellites into orbit in a little over 10 minutes.
This patented air-launch system reduces cost and provides
customers with unparalleled flexibility to operate from virtually
anywhere on Earth with minimal ground support requirements.
Pegasus launches have been conducted from six separate sites
in the U.S., Europe and the Marshall Islands, the first time
a space launch vehicle has demonstrated such operational
flexibility.
Taurus
The Taurus rocket offers an affordable, reliable means of
launching small satellites into low-Earth orbit. Developed
under the sponsorship of the Defense Advanced Research Projects
Agency (DARPA), Taurus was designed for easy transportability
and rapid set-up and launch. Since its debut flight in 1994,
Taurus has conducted six of seven successful missions launching
12 satellites for commercial, civil, military, and international
customers.
Taurus is a ground-based variant of our air-launched Pegasus
rocket. The four stage, inertially guided, all solid propellant
vehicle can deploy 1,350-kilogram (3,000 pound) satellites
into low-Earth orbit. Two fairing sizes offer flexibility
in designing a particular mission, and with the addition
of a structural adapter, either can accommodate multiple
payloads, resulting in lower launch costs for smaller satellites "sharing" a
mission.
A cornerstone of the Taurus program is a simplified integration
and test capability that includes horizontal integration
of the rocket's upper stages and offline encapsulation of
the payload within the fairing. The upper stages and the
encapsulated cargo are delivered to the launch site, where
they are mated. The whole assembly is then stacked on the
first stage using a mobile crane.
The Taurus launch system includes a complete set of ground
support equipment to ensure the ability to operate from austere
sites. Thus far, Taurus has launched from the U.S. Government's
Western range at Vandenberg Air Force Base (VAFB) in California.
Taurus is also approved for launch from Cape Canaveral Air
Station (CCAS) in Florida, Wallops Flight Facility (WFF)
in Virginia, and Kodiak Launch Complex, Alaska.
Titan
The Titan was used by NASA to launch interplanetary missions
from CCAFS. An earlier version of the Titan vehicle, the
Titan III-E/Centaur, built by Martin Marietta and General
Dynamics, was used to launch two Helios missions to the Sun,
two Viking missions to Mars, and two Voyager missions to
Jupiter and Saturn beginning in the 1970s. One of the Voyagers
also continued on to Uranus and Neptune. All of the missions
provided remarkable new scientific data about our Solar System
and spectacular color photographs of the planets they explored,
as well as some of their moons.
The Titan IV launched NASA’s Cassini spacecraft to
Saturn in 1997. The Titan III sent NASA’s Mars Observer
on its journey in 1992. The Titan II was used This Titan
IVB/Centaur rocket launches Oct. 15, 1997, carrying the Cassini
spacecraft.to launch many National Oceanic and Atmospheric
Administration (NOAA) weather satellites. Most recently,
a Titan II launched NASA’s NOAA-M satellite June 24,
2002, from VAFB. |
