Crews for both Apollo 9 and Apollo 10 were in training as 1969 began; on January 9 a third was named, for Apollo 11. Since November 1967 the prime crew of Apollo 9 - James A. McDivitt, David R. Scott, and Russell L. Schweickart - had been following their spacecraft through assembly and rehearsing the complex procedures of orbital rendezvous. Both McDivitt (who came in with the second group of astronauts) and Scott were veterans, each having flown a Gemini mission that had paved the way for rendezvous and docking operations. Schweickart, like Scott, was a "Fourteen" (third group); he had not yet flown a mission but had participated extensively in the development testing of the space suit. The crew of Apollo 10, named on November 12, 1968, was the first in the entire manned space flight program composed entirely of experienced astronauts: Thomas P. Stafford, John W. Young, and Eugene A. Cernan. Stafford, the first of his class to fly two orbital missions, and Young, who had also flown twice, were from the second astronaut class; Cernan, from the third group, had a single flight. They were also the first crew to be promoted as a unit, having served as backup crew on Apollo 7. The crew for Apollo 11, also all veterans, consisted of Neil A. Armstrong from the second group and Edwin E. ("Buzz") Aldrin, Jr., and Michael Collins from the third. Armstrong and Aldrin had been on the backup crew for Apollo 8; the third member of that crew, Fred W. Haise, was replaced by Collins on the flight crew because Deke Slayton wanted an experienced pilot in the command module for Apollo 11, which, if all went well, would most likely be the first mission to attempt a lunar landing.7
The success of Apollo 8 left only the qualification of the lunar module to be accomplished before a lunar landing could be attempted. In the alphabetical sequence of missions adopted a year before, [see Chapter 7] the next mission ("D") was to fly both the command/service module and the lunar module, to check out all LM systems and rendezvous techniques in earth orbit. This, according to 1967 plans, would be followed by missions "E" (combined CSM/LM operations in high earth orbit, later discarded in favor of the "C-prime" mission, Apollo 8, which did not carry a lunar module) and "F" (all operational procedures of a landing mission except the actual landing). On the "F" mission the crew would take the lunar module down to 50,000 feet (15,240 meters) above the moon, get as good a look as possible at the proposed landing site for the first mission, and return to lunar orbit for rendezvous with the command module.8
Mission "D" (Apollo 9) would be the most complex yet flown, involving the checkout of two spacecraft at the Cape and simultaneous operations with two vehicles in orbit. An additional objective was operational checkout of the extra-vehicular space suit and the portable life-support system that lunar explorers would use on the moon's surface.9
Apollo 9 was launched on March 3, 1969, for 10 busy days of operations. After extracting their lunar module from the S-IVB stage, McDivitt and his crewmates performed numerous tests of the engines on both modules, assessing the dynamic behavior of the linked spacecraft as well as the performance of the propulsion systems. On the third day they separated the vehicles and began independent operations, testing the LM systems, and carrying out a complete docking maneuver, all successfully. Schweickart's tests of the extravehicular space suit and lifesupport system were equally gratifying. The most serious anomaly on the flight was the appearance of motion sickness, which had also affected Apollo 8's crew. Schweickart vomited twice and Scott reported being on the verge of nausea for considerable time after reaching orbit. Some tasks had to be cut short on this account, but even so, all the primary mission objectives were satisfied. The Apollo 9 command module came down on March 13 within three miles (4.8 kilometers) of the target point in the western Atlantic.10
Two months later, launch operations crews at Kennedy Space Center were getting ready for the final countdown for Saturn no. 505, the launch vehicle for Apollo 10. This mission was to "confirm all aspects of the lunar landing mission exactly as it would be performed, except for the actual descent, landing, lunar stay, and ascent from the lunar surface." Besides giving the entire mission support team one more workout, it would also allow the manned space flight network to track the spacecraft as it orbited the moon, to provide a more accurate description of the irregular lunar gravitational field.* 11On May 18, the big booster sent CSM 106 and lunar module LM4, with Tom Stafford and his crew aboard, toward the moon on a near-perfect trajectory - one designed to duplicate the path to be taken by the first landing mission. Indicative of the pace of the program in early 1969, even before Apollo 10 reached the moon, Cape crews trundled out Saturn 506, the Apollo 11 launch vehicle, to Launch Complex 39A and began preparing it for its epoch-making flight.12
Stafford, Cernan, and Young carried out their pathfinding mission with remarkably few problems, On the fifth day the lunar module separated from the command module to photograph the approach path, verify the operation of the landing radar, and survey the first landing site** from low altitude. They reported that the landing radar worked as advertised and that the first astronauts to attempt a lunar landing should have no problems finding a smooth level spot in the eastern end of the site; farther west, however, they might have to maneuver to find a boulder- and crater-free area to touch down. That evaluation completed, Stafford and Cernan took their lunar module back into orbit, checking out the abort guidance system as they left low orbit. After rejoining John Young in the command module they headed back to earth, splashing down on May 26 in the Pacific Ocean some 400 miles (650 kilometers) east of Pago Pago.13
* Analysis of irregularities in the orbits of Lunar Orbiter IV had revealed gravity anomalies attributed to concentrations of mass ("mascons") at certain locations on the moon; they were sufficiently large to deflect the path of a lunar module. Results from Apollo 10 would be helpful in developing the capability to land precisely at a targeted spot, which mission planners considered essential for the later missions.
** Site II P-6, [see Chapter 8] just north of the equator in the southwestern part of Mare Tranquillitatis.
7. Brooks, Grimwood, and Swenson, Chariots, pp. 373-77.
8. Ibid., pp. 234-35.
9. Ibid., pp. 290-91.
10. Ibid., pp. 292-99; "Apollo 9 Mission Report," MSC PA-R-69-2, May 1969, pp. 1-1 to 1-2.
11. "Apollo 10 Mission Report," MSC-00126, Aug. 1969, p. 3-1.
12. Charles D. Benson and William Barnaby Faherty, Moonport: A History of Apollo Launch Facilities and Operations, NASA SP-4204 (Washington, 1978), p. 474.
13. Brooks, Grimwood, and Swenson, Chariots, pp. 303-12.