Command Pilot Virgil I. "Gus" Grissom, Senior Pilot Edward H. White II, and Pilot Roger B. Chaffee were killed on January 27, 1967 during a launch rehearsal test.
Following the 1967 Apollo 1 fire disaster, NASA officials contacted Charles Schulz to use Snoopy as their safety mascot. Schulz helped design a pin for the Silver Snoopy award, which was presented to aerospace workers for outstanding contributions toward safer spaceflight operations. Later, during the Apollo 10 mission (which served as the dress rehearsal for the historic Apollo 11 moon landing), NASA dubbed the lunar module “Snoopy” and the command module “Charlie Brown.”(source)