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

50 ballistic missile
ballistic missile
A missile that has a ballistic trajectory over most of its
flight path, regardless of whether or not it carries a
weapon. Ballistic missiles are categorized according to
their range—the maximum distance measured along
Earth’s surface from the point of launch to the point of
impact of the last element of the payload. Various schemes
are used by different countries to categorize the ranges of
ballistic missiles. The U.S. Department of Defense divides
missiles into four range classes, as shown in the table
(“U.S. Ballistic Missile Categories”).
U.S. Ballistic Missile Categories
Type of Missile Range
Intercontinental Over 5,500 km
ballistic missile (ICBM)
Intermediate-range 2,750–5,500 km
ballistic missile (IRBM)
Medium-range 1,100–2,750 km
ballistic missile (MRBM)
Short-range ballistic Up to 1,100 km
missile (SRBM)
Ballistic Missile Defense Organization (BMDO)
An American Department of Defense agency formed in
1994 under the Reagan administration to develop an
antiballistic missile defense, a major part of which would
involve Star Wars weaponry based both on the ground
and in space. Originally intended to counter the threat of
Soviet intercontinental ballistic missiles, BMDO has
shifted its emphasis under the Bush (junior) presidency
to address similar threats from rogue nations with ballistic
and tactical missile technology. Former Strategic
Defense Initiative (SDI) programs to develop Star Wars
weapons, including ASAT (antisatellite) technology, are
being emphasized by the Bush (junior) administration.
Ballistic Research Laboratory
See Aberdeen Proving Ground.
ballistic trajectory
The path followed by an object that is being acted upon
only by gravitational forces and the resistance of the
medium through which it passes.
ballistics
The study of the dynamics of an object moving solely
under the influence of a gravitational field.
ballute
An inflatable balloon-parachute made from a thin, flexible,
inelastic membrane that provides a means of aerobraking
or aerocapture. Typically, ballutes are
pumpkin-shaped and wrinkled in appearance with longitudinal
seams. To reduce heating on the ballute, one
option is to have the main spacecraft engine run at low
idle thrust during aerocapture to provide an aerodynamic
spike, although the ballute would be replaced after each
flight. Stability and heat transfer considerations are critical,
as ballutes are aerodynamically unstable at high
Mach numbers, and radiative heat transfer is significant.
A dramatic example of aerocapture into Jupiter orbit
using a ballute system was depicted in the movie 2010:
The Year We Make Contact (1984).
bandwidth
The range of wavelengths or frequencies to which an
antenna is sensitive.
Bantam-X
A NASA project, managed by the Marshall Space Flight
Center, to develop a reusable small satellite launcher.
barycenter
The center of mass of a system of objects, for example,
the Earth and the Moon, moving under the influence of
their mutual gravity.
BBXRT (Broad-Band X-Ray Telescope)
An instrument that formed part of the Astro-1 payload.
Its flight gave the first opportunity for making X-ray
observations over a broad energy range (0.3–12 keV) with
a moderate energy resolution (typically 90 eV and 150 eV
at 1 and 6 keV, respectively). This energy resolution, coupled
with an extremely low detector background, made
BBXRT a powerful tool for the study of continuum and
line emission from cosmic sources. In spite of some technical
hitches with the instrument’s pointing system during
the mission in 1990, BBXRT successfully performed
around 160 observations of some 80 celestial sources
including clusters of galaxies, active galaxies, supernova
remnants, X-ray binaries, cataclysmic variables, and the
X-ray background.
BE (Beacon Explorer)
Early satellites within NASA’s Explorer series that measured
the total electron count between the spacecraft and
Earth by means of a radio beacon and carried out other