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

22 antiparticle
efficient space propulsion system that would need
only a tiny fraction of the antimatter consumed by a
beamed core engine. It would work by a process called
antiproton-catalyzed microfission (ACMF). 274 Whereas
conventional nuclear fission can only transfer heat
energy from a uranium core to surrounding chemical
propellant, ACMF permits all energy from fission reactions
to be used for propulsion. The result is a more efficient
engine that could be used for interplanetary
manned missions. The ICAN-II (Ion Compressed Antimatter
Nuclear II) spacecraft designed at Penn State
would use the ACMF engine and only 140 ng of antimatter
for a manned 30-day crossing to Mars.
A follow-up to ACMF and ICAN is a spacecraft propelled
by AIM (antiproton initiated microfission/fusion),
in which a small concentration of antimatter and fissionable
material would be used to spark a microfusion reaction
with nearby material. Using 30 to 130 micrograms of
antimatter, an unmanned AIM-powered probe—AIM-
Star—would be able to travel to the Oort Cloud in 50
years, while a greater supply of antiprotons might bring
Alpha Centauri within reach. 190
antiparticle
A counterpart of an ordinary subatomic particle, which
has the same mass and spin but opposite charge. Certain
other properties are also reversed, including the
magnetic moment. Antiparticles are the basis of antimatter.
The antiparticles of the electron, proton, and
neutron are the positron, antiproton, and antineutron,
respectively. An encounter between an electron and a
positron results in the instantaneous total conversion
of the mass of both into energy in the form of gamma
rays. When a proton and an antiproton meet, however,
the outcome is more complicated. Pions are produced,
some of which decay to produce gamma radiation and
others of which decay to produce muons and neutrinos
plus electrons and positrons, which make more gamma
rays.
aphelion
The point in a heliocentric orbit that is farthest from the
Sun.
apoapsis
The point in an orbit that is farthest from the body being
orbited. Special names, such as apogee and aphelion, are
given to this point for familiar systems.
apogee
The point in a geocentric orbit that is farthest from Earth’s
surface.
apogee kick motor
A solid rocket motor, usually permanently attached to a
spacecraft, that circularizes an elliptical transfer orbit by
igniting at apogee (leading to the colloquial phrase “a
kick in the apogee”). It was first used on the early Syncom
satellites in 1963 and 1964 to “kick” the satellite
from a geostationary transfer orbit to a geostationary
orbit. Also known simply as an apogee motor.
Apollo
See article, pages 23–33.
Apollo-Soyuz Test Project (ASTP)
Apollo spacecraft
Launch date: July 15, 1975
Launch vehicle: Saturn IB
Crew
Commander: Thomas Stafford
Command Module pilot: Vance Brand
Docking Module pilot: Donald Slayton
Mission duration: 9 days 1 hr
Splashdown: July 24, 1975
Soyuz 19 spacecraft
Crew
Commander: Aleskei Leonov
Flight engineer: Valeriy Kubasov
Mission duration: 5 days 23 hr
Landing: July 21, 1975
The first international manned spaceflight and a symbolic
end to the nearly 20-year-long Space Race between
the United States and the Soviet Union. Setting political
differences aside, the two superpowers successfully carried
out the first joint on-orbit manned space mission.
ASTP negotiations, begun in 1970, culminated in an
agreement for ASTP flight operations being signed at the
superpower summit in May 1972.
The project was designed mainly to develop and validate
space-based rescue techniques needed by both the
American and the Soviet manned space programs. Science
experiments would be conducted, and the logistics
involved in carrying out joint space operations between
the two nations would be tried and tested, paving the way
for future joint ventures with the Space Shuttle, Mir, and
the International Space Station (ISS). As the American
and Soviet space capsules were incompatible, a new docking
module had to be built with a Soviet port on one side
and an American port on the other. This module also
served as an airlock and a transfer facility, allowing astronauts
and cosmonauts to acclimatize to the atmospheres
(continued on page 34)