Goals: This was America's third attempt to study interplanetary space and photograph the Moon before crashing into the lunar surface.

Accomplishments: A malfunction caused the spacecraft batteries to drain after eight hours. The inert spacecraft missed the Moon and ended up in heliocentric (sun-centered) orbit. Mission controllers tracked it to a distance of 1.3 million kilometers (808,000 miles). Scientists did get back about four hours of data from a gamma ray experiment.