In 1970, Hughes Aircraft Company (HAC) Space and Communications Group offered the first[1] standardized satellite: the HS 333 design.
The early design satellites also relied on spinning at about 30 rpm for stability in orbit.
Several parallel decks, including the top and bottom, were used to mount the propulsion, attitude control, communication, Telemetry & Command (T&C), and power equipment.
The outer surface of the cylindrical body was covered with solar cells to generate power for operating the satellite's electrical equipment.
Batteries provide power during an eclipse when the satellite is in the shadow of the Earth.