Mission Summary
The first major attempt by the United States to land/impact a working scientific instrument on the Moon. Designed by the Jet Propulsion Laboratory, the 727-pound (330 kg) probe had an ambitious, multi-step mission blueprint. It was supposed to take close-up television photos as it zoomed toward the surface, and then drop a rugged, balsa-wood-cushioned capsule down onto the dusty ground to measure moonquakes.
Steering problems derailed the flight almost immediately. A glitch in the rocket's guidance system prevented it from receiving proper steering instructions from the ground, causing the engines to burn too hot and leave the craft moving way too fast.
To make matters worse, a central internal clock failed during the deep-space cruise, accidentally spinning the spacecraft's main radio dish away from Earth and breaking communication with ground control. Unable to receive the necessary steering corrections to fix its speed, the blind and silent probe sailed completely past the Moon on January 28, missing the surface by 22,000 miles (35,000 km). The craft never got its pictures and drifted off into a permanent orbit around the Sun, though it did manage to radio back a few helpful measurements of deep-space radiation before its batteries finally died.
Sources and notes can be found on the Sources page.
