Apollo 10's lunar module was nicknamed Snoopy.
Apollo 10 launched on 18 May 1969 as the final crewed rehearsal for Apollo 11. Its lunar module descended to about 15.6 kilometres above the Moon's surface, testing powered descent, hovering, ascent, and rendezvous procedures without landing. The module was named Snoopy, while Apollo 10's command module was called Charlie Brown.
The names came from characters in the Peanuts comic strip by Charles M. Schulz. NASA used the names informally, and Schulz supported the association because Snoopy had become linked with NASA's safety culture. The lunar module's mission profile made it a close simulation of the Apollo 11 landing, but its descent stage was left in lunar orbit after the ascent stage returned to the command module.
A common mix-up is reversing the two Apollo 10 spacecraft names: Snoopy was the lunar module, and Charlie Brown was the command module. Apollo 10 successfully demonstrated the key operations needed before the first lunar landing.