This was another test flight for NASA's Surveyor lunar lander spacecraft. A malfunction with the rocket left the payload tumbling in the wrong orbit. The payload reentered Earth's atmosphere May 5, 1966.
April 8, 1966: Launch
May 5, 1966: Spacecraft reentered Earth's atmosphere
This was a NASA test to launch a dummy Surveyor lunar lander spacecraft into a barycentric orbit towards a simulated Moon.
Unlike the two previous Surveyor mass model tests, this flight was supposed to demonstrate a restart capability for the Centaur upper stage. The Centaur-Surveyor combination successfully achieved parking orbit around Earth with a first firing, but when it came time for the second firing, the Centaur RL-10 engines fired for only a few seconds instead of the planned 107 seconds.
A thrust imbalance left the payload tumbling and in an incorrect orbit of 113 × 208 miles (182 × 335 kilometers) at a 30.7-degree inclination. The problem was later traced to a hydrogen peroxide leak in the ullage motors of the Centaur stage.
With no hope of reaching its ultimate orbit (planned for 104 × 236,000 miles or 167 × 380,000 kilometers), the payload reentered Earth's atmosphere May 5, 1966.