On Cernan’s second space flight, he was lunar module pilot of Apollo 10, May 18-26, 1969. Apollo 10 was the first comprehensive lunar-orbital qualification and verification flight test of an Apollo lunar module. Cernan was accompanied on the 248,000 nautical sojourn to the moon by Thomas P. Stafford (spacecraft commander) and John W. Young (command module pilot).
Apollo 10 crew briefed on emergency egress slide at pad 39-B
Thomas P. Stafford was the first member of his Naval Academy Class of 1952 to pin on the first, second, and third stars of a General Officer. He flew six rendezvous in space; logged 507 hours and 43 minutes in space flight and wore the Air Force command Pilot Astronaut Wings. He has flown over 127 different types of aircraft and helicopters and four different types of spacecraft.
Although the contractors had shipped excellent spacecrafts, preparations at Kennedy did not go quickly from the assembly building to the launch pad. Testing was delayed several days in order to stay out of the way of Apollo 9 pre-flight activities. Also during maintenance to the Launch Control Center, the electrical power was switched off to replace a valve. The Apollo 10 launch vehicle’s pneumatic controls sensed the power outage, opened some valves and dumped 20,000 liters of fuel on the launch pad.
Even before crawling back into the command module, McDivitt said he was tired and ready for a three-day holiday. Another 140 hours would pass before touchdown in the Atlantic, but the crew had achieved more than 90 percent of the mission objectives.
Rusty Schweickart’s Practice Suit for Apollo 9. Pic taken at Wallops
On the fourth day of the flight of Apollo 9, Schweickart felt better than expected as he worked his way into the lander to get it ready for the EVA. By the time he had put on the backpack, McDivitt was ready to let him do more – to stand on the lunar lander porch at least.
Lunar Module to Command Module transfer procedure
Schweickart on the porch of the Lunar Module
Scott standing in the open hatch of the Command Module
As Dave Scott pulled in closer to the Lunar Module he noticed that the command module’s nose was out of line with the lander’s nose. Scott tried to use a service module thruster to turn left, but that jet was not operating. It turns out that someone had accidentally bumped a switch that turned off one set of Thrusters. The crew then flipped the correct switches, and the thruster started working, and at T+3 hours 2 minutes the command module probe nestled into the lunar Module drogue, where it was captured and held by the 12 latches. The first docking of the Lunar Module in space was achieved. As a side note, switch guards were installed on all future Apollo missions to prevent accidentally flipping a switch.
LM on S-VIB stage preparing to dock with the Command Module