TIROS-3 was launched on July 12, 1961, by a Thor-Delta rocket from Cape Canaveral Air Force Station, Florida.

The top and sides of the spacecraft were covered with approximately 9000 1- by 2-cm silicon solar cells.

[3] The satellite spin rate was maintained between 8 and 12 rpm by use of five diametrically opposed pairs of small, solid-fuel thrusters.

The satellite spin axis could be oriented to within 1- to 2-deg accuracy by use of a magnetic control device consisting of 250 cores of wire wound around the outer surface of the spacecraft.

The flight control system also optimized the performance of the solar cells and TV cameras and protected the five-channel infrared radiometer from prolonged exposure to direct sunlight.