It was equipped to take images of the lunar surface with a television-like system, estimate the Moon's mass and topography of the poles, record the distribution and velocity of micrometeorites, and study radiation, magnetic fields, and low frequency electromagnetic waves in space.

The launch took place on Thanksgiving, 26 November 1959 from LC-14 at Cape Canaveral Air Station using Atlas vehicle 20D, which had originally been the backup booster for the Mercury Big Joe test in September.

Because 20D had been custom-built for the Mercury program, it had thicker-gauge skin than the standard Atlas ICBM and could support the additional weight of upper stages.

All proceeded normally until T+45 seconds when a shock was recorded by the Atlas's rate gyros followed by the fiberglass payload fairing breaking off of the launch vehicle.

Pioneer P-3 was a 1-meter diameter sphere with a monopropellant propulsion system mounted on the bottom giving a total length of 1.4 meters.

The blades themselves were made of reflective material and consist of four vanes that were flush against the surface, covering a black heat-absorbing pattern painted on the sphere.