Less than three weeks before their mission, Apollo 10 astronauts Thomas P. Stafford, Eugene A. Cernan and John W. Young met with the press on April 26, 1969, at the Manned Spacecraft Center, now the Johnson Space Center in Houston.
The trio described to the assembled reporters their upcoming flight, which essentially would be a dress rehearsal for the Moon landing.
Once in lunar orbit, Stafford and Cernan aboard their Lunar Module Snoopy would descend to about 50,000 feet above the Moon’s surface, and photograph the primary landing site for Apollo 11 in the Sea of Tranquility. Snoopy would travel up to 350 miles from Young in the Command and Service Module Charlie Brown during these maneuvers. Simulating a litfoff from the Moon, and Stafford and Cernan would then complete a rendezvous and docking with Young in the CSM.
As part of that inspection, they would take stereo photographs to obtain the highest resolution images of the site. They would also activate the LM’s landing radar during the low passes, a critical test before the Moon landing. Regarding the complexity of the mission, Cernan added “I’ve never been involved in anything that has required as great an amount of coordination and team work as … to work with two vehicles in a lunar environment.”
When not speaking with the press, Stafford, Cernan and Young spent time nearly daily in the LM and Command Module simulators rehearsing various aspects of their upcoming mission. During many of these simulations, Mission Control in Houston was tied in to give flight controllers practice. The astronauts also spent time reviewing procedures, updating checklists, and receiving briefings on spacecraft systems and lunar topography.
Managers from NASA Headquarters, KSC, MSC and the Marshall Space Flight Center met at KSC on April 23 to conduct the Flight Readiness Review for Apollo 10. At the conclusion of the meeting, during which they reviewed all aspects of the flight hardware as well as the readiness of the crew, the control centers, and the Manned Spaceflight Network, the managers decided that the mission was ready to proceed with a launch on May 18. The Countdown Demonstration Test, a final dress rehearsal of the countdown, was scheduled to be conducted between April 29 and May 6, with the three crewmembers participating in the final phase as if on launch day.
Even as the Apollo 10 flight was approaching its launch, NASA was preparing for the Moon landing mission itself, Apollo 11 planned for July.
While test flights with NASA pilots continued with the Lunar Landing Training Vehicle at Ellington Air Force Base near MSC, Apollo 11 crewmembers made use of the Lunar Landing Research Facility at the NASA Langley Research Center in Virginia, to train for the final descent to the lunar surface.
Backup crew Commander James A. Lovell and backup Lunar Module Pilot Fred W. Haise practiced Moon landings in the LLRF in mid-April. Prime crew Commander Neil A. Armstrong and prime LMP Edwin E. “Buzz” Aldrin would use the facility for practice landings in late June. Once the LLTV was cleared for astronaut training in early June, Armstrong and Lovell completed training flights in that higher fidelity vehicle later that month. Because the LLTV was a single-seat vehicle, and there was limited time available for training, only prime and backup commanders trained with it, while the LLRF was available to both commanders and LMPs.
At MSC, Armstrong, Aldrin, Lovell, and Haise each completed sea-level runs in Chamber B of the Space Environment Simulation Laboratory. During these tests, the astronauts wore their spacesuits and practiced the various activities of the lunar surface Extravehicular Activity, such as activating the television camera, collecting rock samples, and deploying the scientific experiments of the Early Apollo Surface Experiment Package. They followed up these ambient sessions with altitude runs in early May.
NASA was even looking beyond the first landing, making preparations for Apollo 12, the second Moon landing expected to occur about four months after the first. Hardware for this mission had begun to arrive at KSC in March, including the Saturn V rocket’s S-II second and S-IVB third stages, the LM and the CSM. The Apollo 12 crew of Charles “Pete” Conrad, Alan L. Bean and Richard F. Gordon, announced in early April, was already in training and preparing for the first geology field trip to Hawaii in early May.