The Apollo 10 mission was a dress rehearsal for the first lunar landing attempt. Astronauts Tom Stafford and Eugene Cernan took their lunar module (nicknamed Snoopy) down to 50,000 feet above the moon’s surface. It is at this point during a lunar landing mission that the lunar module’s descent engine would be fired for about 12 minutes, braking the spacecraft out of lunar orbit toward the surface. Meanwhile, astronaut John Young remained in the Command Service Module (nicknamed Charlie Brown) waiting for the lunar module to return.