The Complete Book of Spaceflight: From Apollo 1 to Zero Gravity

astronaut
A person who flies in space as a crew member or a passenger.
87 More specifically, someone who flies aboard an
American spacecraft. See cosmonaut.
astronautics
The science of spaceflight, including the building and
operation of space vehicles.
astronomical unit (AU)
The mean distance between Earth and the Sun. One AU
= 149,597,870 km = 92,955,806 miles = 499 light-seconds.
One light-year = 63,240 AU.
astronomy satellites
Spacecraft dedicated to making observations of natural
objects in space, including the Sun and other stars, nebulae,
galaxies, and quasars. 188
Asuka
See ASCA.
Athena (launch vehicle)
A family of solid-propellant launch vehicles built by
Lockheed-Martin for delivering small payloads into LEO
(low Earth orbit), geostationary transfer orbit (GTO), or
interplanetary orbits. After a string of seven commercial
launch successes, the prospects for Athena I are uncertain
with the shrinkage in the market for small commercial
satellite launches. However, the future for Athena II
brightened in 2001 when NASA added the rocket to its
launch services contract along with the Delta and the
Atlas.
The Athena program was begun in January 1993 by
Lockheed to apply its expertise in solid-propellant missile
technology, developed as a result of the Polaris, Poseidon,
and Trident programs, to launching lightweight payloads
into space. What was initially called the Lockheed
Launch Vehicle (LLV) became the Lockheed Martin
Launch Vehicle (LMLV), following Lockheed’s merger
with Martin Marietta to form Lockheed Martin. The core
launch vehicle was named LMLV-1, with a larger version
named LMLV-2. Later, LMLV-1 was renamed Athena I,
while LMLV-2 became the Athena II. The first launch of
an Athena rocket took place in August 1995 and ended
in failure. But more recently, Athena I and Athena II
vehicles have been used to launch NASA’s Lewis and
Lunar Prospector missions, ROCSAT-1 for the People’s
Republic of China, and four small satellites in a single
launch from Kodiak Launch Complex—a first for the
new Alaskan rocket site.
atmosphere 43
The Athena launch system integrates several different
solid motor stages and common equipment to create
the two-stage Athena I and the three-stage Athena II.
Common to the two vehicles are the avionics package,
the separation system, the destruct system, and the
launch equipment. The Athena I has a first stage with a
Thiokol Castor 120 solid motor, a second stage with
a Pratt & Whitney Orbus 21D solid motor, and a
hydrazine-fueled Primex Technologies Orbit Adjust
Module (OAM). The Athena II uses the same stack but
adds another stage with a Castor 120. (See table, “Athena
Launch Vehicles.”)
Athena Launch Vehicles
Athena I Athena II
Overall length 19.8 m 28.2 m
Core diameter 2.4 m 2.4 m
Payload to LEO
Thrust
794 kg 1,896 kg
First stage 1,900,000 N 1,900,000 N
Second stage 194,000 N 1,900,000 N
Third stage — 194,000 N
Athena Science Payload
See Mars Exploration Rovers.
Atlantic Missile Range (AMR)
An instrumented missile test range extending 8,000 to
9,700 km from Cape Canaveral to a point beyond Ascension
Auxiliary Air Force Base. It includes a series of
island-based tracking stations and ocean-range vessels to
gather performance data.
Atlantis
A Space Shuttle Orbiter, also designated OV-104. Atlantis
was named in honor of a two-masted ketch that supported
oceanographic research for the Woods Hole
Oceanographic Institute in Massachusetts between 1930
and 1966. It first flew on October 3, 1985, as mission
STS-51J. Other Atlantis milestones have included the
deployment of Magellan (STS-30) and Galileo (STS-34),
and the first docking of a Space Shuttle to the Mir space
station (STS-71).
Atlas
See article, pages 44–46.
atmosphere
A layer of gases surrounding Earth or some other planet.
Above the troposphere (which extends from the ground
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