In addition , several unmanned landing missions achieved the Lunar surface .
Were unsuccessful , including : Luna 15 , Luna 18 , and Luna 23 all crashed on landing ; and the U.S. Surveyor 4 lost all radio contact only moments before its landing .
In addition , several unmanned landing missions achieved the Lunar surface but were unsuccessful , including : Luna 15 , Luna 18 , and Luna 23 all crashed on landing ; and the U.S. Surveyor 4 lost all radio contact only moments before its landing .