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

SSF (subsatellite ferrets)
Classified U.S. Air Force subsatellites, released in association
with other military launches, that carried out radio
and radar signals intelligence gathering. There have been
several types, dating back to the 1963 “Hitch Hiker”
spacecraft, but details remain secret.
SSS (Small Scientific Satellite)
A NASA spacecraft launched from San Marco to measure
aerodynamic heating and radiation damage during
launch, and also to investigate particles and fields in the
magnetosphere. Also known as Explorer 45.
stabilization of satellites
Satellite stabilization takes three possible forms: (1) spin
stabilization, whereby the satellite is spun at 10 to 30
rpm; (2) gravity gradient stabilization using a large
weight attached to the satellite by a length of line; and (3)
inertial stabilization using heavy wheels rotating at high
speed—typically three wheels, one for each axis, providing
three-axis stabilization.
Stack, John (1906–1972)
An American aeronautical engineer who played an important
role in the effort to achieve manned supersonic
flight. Stack graduated from the Massachusetts Institute
of Technology in 1928 and then joined the Langley
Aeronautical Laboratory, becoming director of all the
high-speed wind tunnels and high-velocity airflow research
there in 1939. Three years later, he was named chief of
the compressibility research division at Langley. In 1947,
he was promoted to assistant chief of research, a title then
changed to assistant director of the research center. Stack
guided much of the research that paved the way for transonic
aircraft, and in 1947 was awarded the Collier Trophy
together with Charles Yeager, the pilot who first
broke the sound barrier. From 1961 to 1962, Stack was
director of aeronautical research at NASA Headquarters
before leaving to become vice president for engineering
at Republic Aircraft Corp (later part of Fairchild Industries),
from which he retired in 1971.
Stacksat
An American military project that involved the simultaneous
launch of three similar spacecraft: POGS (Polar
Orbiting Geomagnetic Survey), TEX (Transceiver Experiment),
and SCE (Selective Communications Experiment).
POGS carried a magnetometer to map Earth’s
magnetic field. Data from the experiment was stored in
an experimental solid state recorder and was used to help
improve Earth navigation systems. TEX carried a variable
power transmitter to study ionospheric effects on radio
frequency (RF) transmissions and gather data to deter-
Stafford, Thomas P. 413
mine minimum spacecraft transmitter power levels for
transmission to ground receivers. SCE carried a variable
frequency transmitter to study ionospheric effects at various
RF frequencies and was also designed to demonstrate
message store and forward techniques. Six low-cost
ground stations were designed, built, and located around
the world to operate these spacecraft.
Launch
Date: April 11, 1990
Vehicle: Atlas E
Site: Cape Canaveral
Orbit (circular): 741 km × 90°
Mass (each): 68 to 72.6 kg
Stafford, Thomas P. (1930–)
A veteran American astronaut and career Air Force officer,
selected by NASA in 1962. Stafford served as backup
Thomas Stafford Stafford (standing) and Walter Schirra go
through a suit-up exercise in preparation for their Gemini 6
flight in 1965. NASA