Canceled Apollo missions planning their own circumlunar flight for December to upstage the Americans once again (see Zond program). McDivitt's crew—who had grown accustomed to working with LM-3 and preparing for its flight—was kept on the D mission which now became Apollo 9, while Borman's crew would fly the CSM lunar orbit mission on Apollo 8, and the E mission was canceled. The swap of crews was also decisive in who would be the first man to walk on the Moon. Pete Conrad was backup Commander for McDivitt's crew, and by the process of crew rotation, would have been in line for Commander
Apollo 10 According to the 2002 "Guinness World Records", Apollo 10 set the record for the highest speed attained by a manned vehicle: 39,897 km/h (11.08 km/s or 24,791 mph) on May 26, 1969, during the return from the Moon. The mission's call signs were the names of the "Peanuts" characters Charlie Brown and Snoopy, which became Apollo 10's semi-official mascots. "Peanuts" creator Charles Schulz also drew some mission-related artwork for NASA. Apollo 10 and Apollo 11 were the only Apollo missions whose crew were all veterans of spaceflight. Thomas P. Stafford had flown on Gemini 6 and Gemini 9; John W.