Discoverer 1 was a test of the performance capabilities of the propulsion and
guidance system of the booster and satellite. It was the first of a series of satellites which were part of the Corona reconnaissance satellite program. Launch took place from Vandenberg
Air Force Base on a Thor-Agena A (1e launch). After first stage burnout at 28529 km/hr the
rocket coasted to orbital altitude where the second stage guidance system
oriented the spacecraft by means of pneumatic nitrogen jets. The second stage
engine ignited when the correct attitude was achieved, putting the spacecraft
into a polar orbit where it remained until re-entry on 17 March 1959. Discoverer
1 became the first man-made object ever put into a polar orbit. Difficulty was
encountered receiving signals after launch, but the satellite broadcast
intermittently later in the flight.
Discoverer 1 was a 5.73 m long, 1.52 m diameter cylindrical Agena A upper
stage capped by a conical nosecone. The satellite casing was made of magnesium.
Most of the 18 kg payload, consisting of communication and telemetry equipment,
was housed in the nosecone. It included a high-frequency low-power beacon
transmitter for tracking and a radar beacon transmitter with a transponder to
receive command signals and allow long-range radar tracking. Fifteen telemetry
channels (10 continuous and 5 commuted) were used to relay roughly 100 aspects
of spacecraft performance.
It was a prototype of the KH-1 satellite, but didn't contain either a camera or a film capsule.