Explorer 35, also known as the Anchored Interplanetary Monitoring Platform (AIMP-E or AIMP-6) was designed to study interplanetary space phenomena, particularly the solar wind, the interplanetary magnetic field, dust distribution near the Moon, the lunar gravitational field, the weak lunar ionosphere, and the radiation environment.

The mission of Surveyor 4 was to demonstrate the technology necessary to achieve landing and operations on the lunar surface. Radio signals from the spacecraft stopped a few minutes before landing and contact was never reestablished.