AEM 2

Launch data: Designation 11270 / 79013A Launch date 18 Feb 1979 Launch site WI, LA-3 Launch vehicle Scout-D1 (#99) Mission Scientific: high atmosphere study Near-circular non-synchronous Earth orbit: Perigee / Apogee  548 x 660 km Eccentricity   Inclination  55 deg Period  96.8 min

Spacecraft data: Prime manufacturer  Boeing Aerospace Company Platform   Operator   Mass at launch  147 kg Dry Mass   kg Basic shape  six-sided prism Dimension  height= 65 cm, overall length, including antennas= 1.62 m Equipment  conical log spiral S-band antenna and two VHF antennas Solar array  two solar panels Stabilization  three-axis stabilization Propulsion   DC power

Illustration of the SAGE instrument as part of the AEM-2 spacecraft (image credit: NASA)

End of life

Descriptions:

• The small low-cost AEM-2 minisatellite was developed and built at the Boeing Aerospace Company consisting of two distinct modules: the spacecraft base module and the instrument module. The base module is a small, hexagonal prism containing power, command, communications, data handling and attitude control subsystems to support the instrument module. The base module includes a PCM (Pulse-Code Modulation) telemetry data system and a communications subsystem that makes use of a conical log spiral S-band antenna and two VHF antennas.
• The base module is spin-stabilized, with three-axis stabilization provided by an active reaction wheel and a magnetic torquing system (the attitude determination hardware consists of five Adcole two-axis DSS, two Hughes HS scanners, and a TAM). The required attitude determination accuracies are: roll 0.7º, pitch 0.5º, and yaw 2.0º in operational mode. A hydrazine orbit adjust system provides the capability to minimize orbit variations to assure adequate mapping by the on-board instrument.
• The spacecraft had a launch mass of 147 kg. The base module (six-sided prism) had a height of 65 cm. The overall height of the spacecraft, including antenna, was 1.62 m. Power was provided by two solar paddels and batteries.

Mission details:

• The NASA satellite was used in 1979-81 to study the ozone layer as part of the Applications Explorer program.
• The spacecraft experienced power problems after May 15, 1979. However, the spacecraft operations continued until November 19, 1981 (providing a data set of ~ 2 1/2 years). The signal from the spacecraft was last received on January 7, 1982, when the battery failed. On April 11, 1989, the spacecraft decayed in the atmosphere.

External links:

• EOportal.org Satellite description