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

382 SMEX (Small Explorer)
Space Flight Center. The scientific payload included an
ultraviolet ozone spectrometer, a1.27-micron spectrometer,
anitrogen dioxide spectrometer, a4-channel infrared
radiometer,asolarultravioletmonitor,andasolarproton
alarm detector. All instruments were turned off in
December 1988, and contact was lost permanently on
April 14, 1989, following abattery failure.
SMEX (Small Explorer)
A series of low-cost satellites launched by NASA for solar
and astronomical studies. The first four spacecraft in the
series were SAMPEX (Solar Anomalous and Magnetospheric
Particle Explorer), FAST (Fast Auroral Snapshot
Explorer), TRACE (Transition Region and Coronal
Explorer), and SWAS (Submillimeter Wave Astronomy
Satellite).
SMEX lite
A design, stemming from early experience with the
SMEX program, for a new system architecture intended
to provide ultra-low-cost small spacecraft whose performance
exceeds that of the initial five SMEX missions.
SMEX lite has been developed at the Goddard Space
Flight Center.
SMM (Solar Maximum Mission)
A NASA spacecraft equipped to study solar flares and
other high-energy solar phenomena. Launched during a
peak of solar activity, SMM observed more than 12,000
flares and over 1,200 coronal mass ejections during its
10-year lifetime. It provided measurements of total
solar radiative output, transition region magnetic field
strengths, storage and release of flare energy, particle
accelerations, and the formation of hot plasma. Observations
from SMM were coordinated with in situ measurements
of flare particle emissions made by ISEE-3
(International Sun-Earth Explorer 3). SMM was the first
satellite to be retrieved, repaired, and redeployed in orbit:
in 1984, the STS-41 Shuttle crew restored the spacecraft’s
malfunctioning attitude control system and replaced a
failed electronics box. SMM collected data until November
24, 1989.
SMS Series
Launch
Date: February 14, 1980
Vehicle: Delta 3914
Site: Cape Canaveral
Orbit: 405 × 408 km × 28.5°
Mass: 2,315 kg
Length: 4.0 m
SMS (Synchronous Meteorological Satellite)
Weather satellites in geostationary orbit, managed by
NASA for NOAA (National Oceanic and Atmospheric
Administration). SMS-1 and -2 were development satellites
leading up to the GOES (Geostationary Operational
Environment Satellite) program; in fact, SMS 3
became operational as GOES-1. (See table, “SMS Series.”)
Launch
Vehicle: Delta 2914
Site: Cape Canaveral
SNAP (Systems for Nuclear Auxiliary Power)
A program of experimental radioisotope thermonuclear
generators (RTGs) and space nuclear reactors flown during
the 1960s. Odd-numbered SNAPs were RTG tests,
and even-numbered SNAPs were reactor system tests.
The United States flew only one complete nuclear reactor,
aboard the SNAPSHOT mission.
SNAPSHOT
The first, and so far only, American flight of an operational
nuclear space reactor. The SNAP-10A reactor produced
650 W of power from 1.3 kg of used uranium-235
fuel (embedded in uranium zirconium hydride) to run a
small ion propulsion system.
Launch
Date: April 3, 1965
Vehicle: Atlas-Agena D
Site: Vandenberg Air Force Base
Mass: 440 kg
Orbit: 1,270 × 1,314 km × 90°
Spacecraft Launch Date Orbit Mass (kg)
SMS 1 May 17, 1974 36,216 × 36,303 km × 15.5° 243
SMS 2 Feb. 6, 1975 35,941 × 36,060 km × 12.0° 627
SMS 3 See GOES-1