On May 18, 1969, the Apollo 10 mission lifted off from the Kennedy Space Center in Florida. This was the only Apollo mission to launch from Launch Complex 39B. The purpose of the Apollo 10 mission was to conduct a full test of the lunar module in lunar orbit, obtain close up photography of the landing site for Apollo 11 and verify all mission procedures without landing on the Moon. Objectives included a scheduled eight-hour lunar orbit of the separated lunar module and descent to about nine miles above the moon’s surface. The lunar module ascent stage would then separate from the descent stage and ascend for rendezvous and docking with the command and service module in a 70-mile circular lunar orbit.
The previous Apollo 8 mission had tested the Saturn V rocket and the command and service modules by sending 3 astronauts to orbit the Moon in December 1968. The next mission, Apollo 9 in March 1969, was the first test flight of the lunar module with astronauts in Earth orbit. Apollo 9 tested out rendezvous and docking procedures that would be needed for a lunar landing. The Apollo 10 mission would continue the testing of the lunar module, but in lunar orbit to make sure everything worked as planned before giving the go ahead for a landing on the next mission, Apollo 11.
The crew for Apollo 10 were all veterans of the Gemini program and had flown in space previously. Commander Thomas P. Stafford had flown on Gemini 6 and Gemini 9; Command Module Pilot John W. Young had flown on Gemini 3 and Gemini 10, and Lunar Module Pilot Eugene A. Cernan had flown with Stafford on Gemini 9.
The Apollo 10 command module was named Charlie Brown and the lunar module was named Snoopy, both from the “Peanuts” comic strip. Apollo 10 was the first mission to carry a color television camera inside the spacecraft and made the first live color TV transmissions from space.
Snoopy and Charlie Brown in Mission Control (NASA) Stafford pats the mission mascot, Snoopy the dog (NASA)
Lunar Module Snoopy Command Module Charlie Brown
Commander Stafford and Lunar Module Pilot Cernan entered the Lunar Module Snoopy and prepared for the undocking maneuver on May 22. Command Module Pilot Young would remain behind and fly Charlie Brown solo. At about 100 hours into the mission, Charlie Brown and Snoopy separated and briefly flew a station-keeping lunar orbit of 66.7 by 71.5 miles. To achieve a simulation of the future Apollo 11 landing, Snoopy’s descent engine was fired, and the lunar module descended to within only eight nautical miles of the Moon’s surface. The astronauts flew over the selected future landing site of Apollo 11 in the Sea of Tranquility, scouting out the area in detail. The crew then jettisoned the lunar module descent stage and fired the engine of the ascent stage to return to Charlie Brown. During descent stage separation Snoopy experienced some unexpected motions in all three axes that Stafford and Cernan quickly brought under control. The gyrations were later attributed to a switch placed in the wrong position.
After successfully docking with the command module Charlie Brown, the 3 astronauts fired the service module engine to return to Earth. Stafford, Young and Cernan splash downed in the Pacific Ocean on May 26, 1969, about 400 nautical miles east of American Samoa. The success of Apollo 10 would give NASA the green light to land on the Moon with the next mission in July 1969, Apollo 11.
All three Apollo 10 astronauts would fly again. Stafford would command the Apollo/Soyuz mission in 1975, Cernan would command Apollo 17 and Young would command Apollo 16 as well as two space shuttle flights including the first flight of Columbia in 1981.