Axial Thruster
Used for positioning and station acquisition maneuvers,
and maybe used for orbit control
Despun Section
Earth-oriented, helix dish antenna assemblies in section
that does not spin
Earth sensors
Used for attitude determination during the transfer orbit
and synchronous orbit, provides pitch, yaw, and roll
information to maintain Earth-pointing
EPS dome
Covers the Energetic Particle Sensor
EPS telescope
Energetic Particle Sensor, measures low and medium-charged particles
High Energy Proton and Alpha Particle Detector (HEPAD)
Monitors protons in four energy ranges above 370 MeV (rest mass in electron-volts),
and alpha particles in two energy ranges above 640 MeV/nucleon
Magnetometer
Measures the magnitude and field direction of energetic charged particles within the
Earth’s magnetosphere (within a specified range)
Radial Thrusters
Used for spin-rate control, range of 110-80 rpm
S-Band Bicone Omni Antenna
Part of telemetry and command subsystem
S-Band High Gain Antenna
Part of telemetry and command subsystem