Mission Summary
Surveyor 4 was lost in the final moments of an otherwise flawless flight, just seconds before it would have landed. Launched July 14, 1967, it carried the same surface-sampling claw as its predecessors, now fitted with a magnet to detect iron in the lunar soil, and was bound for Sinus Medii near the center of the Moon’s near side.
The mission went smoothly all the way to the descent. Then, only about two and a half minutes before touchdown, and just two seconds before the braking rocket was due to shut down, all contact with the spacecraft abruptly ceased.
Surveyor 4 was never heard from again. NASA concluded that the solid-propellant retro-rocket had most likely exploded, destroying the lander on its way down. The loss interrupted the Surveyor program’s run of successful landings, though the flights that followed would restore it.
Sources and notes can be found on the Sources page.
