12 May 1965

The Soviet spacecraft Luna 5 crashes on the Moon.

In May 1965, Luna 5 became the first Soviet probe in two years to head for the Moon. Following a May 10 midcourse correction, a problem developed in a flotation gyroscope in the I-100 guidance control unit. Control was lost so the spacecraft began spinning around its main axis.

Ground controllers regained control of the spacecraft, but at the time of the next maneuver the main retrorocket system failed due to a ground control error in calculating the setpoints. As a result, the spacecraft, though still headed for the Moon, was far off its intended landing site. Problems again cropped up with the I-100 unit so a retrorocket burn could not take place and Luna 5 impacted the lunar surface some 430 miles from the target point at about 19:10 UT on May 12, 1965, becoming the second Soviet probe to hit the Moon.

A Soviet announcement gave the impact point as the Sea of Clouds at roughly 31 degrees S, 8 degrees W. Although a later analysis gave a very different estimate of 8 degrees N, 23 degrees W..

Despite failing at its ultimate objective of a soft landing on the Moon’s surface, the spacecraft was a partial success because, unlike its predecessor Luna 4, it successfully performed a midcourse correction.