|1||Anticoincidence Counter||8||Sun and Earth Albedo Sensors (Attitude Measurement)|
|2||Spark Chamber||9||Spin Thruster|
|3||Triggering Telescope||10||Precession Thruster (Attitude Control)|
|4||Energy Calorimeter||11||Nitrogen Tank (Attitude Control)|
|5||Pulsar Synchronizer||12||Neon Tank (Gas Flushing, Spark Chamber)|
Cos-B was configured as a cylinder 1.40 m in diameter and 1.13 m long, with the main experiment package occupying the central region. The total mass at launch was 278 kg, of which the experiment was 118 kg.