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

case of an Earth satellite) defines the orientation of the
orbit with respect to Earth’s equator; (4) the argument of
perigee, which defines where the perigee (low point) of
the orbit is with respect to Earth’s surface; (5) the right
ascension of the ascending node, which defines the location
of the ascending and descending points with respect
to Earth’s equatorial plane; and (6) the true/mean anomaly,
which defines where the satellite is within the orbit
with respect to perigee.
orbital energy
The sum of the potential and kinetic energies of an object
in orbit.
orbital nodes
Points in an orbit where the orbit crosses a reference
plane, such as the ecliptic (the plane of Earth’s orbit) or
the equatorial plane.
orbital period
The time taken for an object to go once around a closed
orbit. It is related to the semi-major axis in a way that is
defined by the third of Kepler’s laws.
orbital plane
The plane defined by the motion of an object about a
primary body. The position and velocity vectors lie
within the orbital plane, whereas the angular momentum
vector is at right angles to the orbital plane.
orbital velocity
The velocity required to establish and to maintain a satellite
in orbit. The term refers to average velocity, since the
velocity is greater at perigee (the point of minimum altitude)
than at apogee (the point of maximum altitude).
orbiter
The portion of a spacecraft that orbits a celestial body,
such as a planet.
Orbiter
The orbiting portion of the Space Shuttle.
Orbiter, Project
A joint U.S. Army/Office of Naval Research plan for
launching satellites during the International Geophysical
Year.
Orbiter Processing Facility (OPF)
A facility at Kennedy Space Center used for refurbishing
the Space Shuttle Orbiter and for loading payloads.
Origins program 307
OrbView
Satellites designed to provide high-resolution images of
Earth from orbit, which ORBIMAGE (Orbiting Image
Corporation), a company half-owned by Orbital Sciences,
sells to civilian, government, and military customers.
OrbView-1, launched in 1995, and originally called
MicroLab, provides atmospheric imagery; OrbView-2,
launched in 1997, and originally called Seastar, supplies
images of both ocean and land. OrbView-4 carried a
camera able to snap 1-m resolution black-and-white and
4-m resolution color images from a 470-km orbit. It also
carried a hyperspectral imaging instrument for the Air
Force Research Laboratory’s Warfighter-1 program,
which would have made it the first commercial satellite
to produce hyperspectral imagery. The U.S. military is
interested in this technique because it shows promise for
detecting chemical or biological weapons, collecting
bomb damage assessment for commanders, and finding
soldiers and enemy vehicles hidden under foliage. However,
OrbView-4 was lost minutes after a faulty launch
by its Taurus booster on September 21, 2001. (Also destroyed
on the same flight was NASA’S QuikTOMS.)
OrbView-3, which carries the same camera as its ill-fated
sibling, but not the hyperspectral imager, will be
launched aboard a Pegasus rocket sometime after September
2002.
Ordway, Frederick Ira III (1927–)
A space scientist and a well-known author of visionary
books on spaceflight. Ordway was in charge of space systems
information at the Marshall Space Flight Center
from 1960 to 1963 and before that performed a similar
function for the Army Ballistic Missile Agency. For
many years he was a professor at the University of
Alabama’s School of Graduate Studies and Research.
However, his greatest contribution has been to the popularization
of space travel through dozens of books that he
has authored or coauthored. He was also a technical consultant
to the film 2001: A Space Odyssey and owns a large
collection of original paintings depicting astronautical
themes. 226 Ordway was educated at Harvard and completed
several years of graduate study at the University of
Paris and other universities in Europe.
ORFEUS (Orbiting and Retrievable Far and
Extreme Ultraviolet Spectrometer)
See SPAS.
Origins program
A NASA initiative designed to explore, through a series
of space projects over the first two decades of the twenty-