Apollo 10 - Mission Highlights

Mission Highlights

This dress rehearsal for a Moon landing brought Stafford and Cernan's lunar module Snoopy to 8.4 nautical miles (15.6 km) from the lunar surface. The low approach orbit was to refine the lunar gravitational potential needed to calibrate the powered descent guidance system to within 1-nautical-mile (1.9 km) (LR altitude update lock) needed for a landing. Earth-based observations, unmanned spacecraft, and Apollo 8 respectively had allowed calibration to 200 nautical miles (370 km), 20 nautical miles (37 km), and 5 nautical miles (9.3 km). Except for that final stretch, the mission went exactly as a landing would have gone, both in space and on the ground, putting Apollo's extensive tracking and control network through a dry run.

Shortly after leaving low Earth orbit, the command/service module separated from the S-IVB stage, turned around, and docked its nose to the top of the lunar module still nestled in the S-IVB. The CSM/LM stack then separated from the S-IVB for the trip to the Moon.

Apollo 10 was the first to carry a color television camera inside the spacecraft, and made the first live color TV broadcasts from space.

Upon reaching lunar orbit, Young remained alone in the command module Charlie Brown while Stafford and Cernan flew separately in the LM. The LM crew checked out their craft's radar and ascent engine, rode out a momentary gyration in the lunar lander's motion (due to a faulty switch setting), and surveyed the Apollo 11 landing site in the Sea of Tranquility. NASA took special precaution to ensure Stafford and Cernan would not attempt to make the first landing. According to Cernan, "A lot of people thought about the kind of people we were: 'Don't give those guys an opportunity to land, 'cause they might!' So the ascent module, the part we lifted off the lunar surface with, was short-fueled. The fuel tanks weren't full. So had we literally tried to land on the Moon, we couldn't have gotten off." The fueled Apollo 10 LM weighed 30,735 pounds (13,941 kg), compared to 33,278 pounds (15,095 kg) for the Apollo 11 LM which made the first landing.

Splashdown occurred in the Pacific Ocean on May 26, 1969 at 16:52:23 UTC, approximately 400 nautical miles (740 km) east of American Samoa. The astronauts were recovered by the USS Princeton, and subsequently flown to Pago Pago International Airport in Tafuna for a greeting reception, before being flown on a C-141 cargo plane to Honolulu.