Trip to Tranquility

1969: July

In the summer of 1968, a group led by John R. Sevier in Houston studied hundreds of possible lunar landing sites. A lot was involved in setting the lunar module down on the moon - keeping the vehicle stable; gauging surface slopes and boulder distribution; controlling forward, lateral, and vertical speeds during the final few seconds before committing to a landing; and finally cutting off the engine at the proper instant. The spacecraft was equipped to make an automatic, hands-off landing, but analyses of site survey photographs indicated that in such a landing the vehicle would overturn 7 out of 100 times. Sevier's group contended that a manually controlled touchdown by the astronauts faced better odds. Using a lunar surface model complete with craters and hills and illuminated to match a particular time and date, the analysts demonstrated that the pilots could recognize the high slopes and craters in time to fly over and land beyond them and that there would be enough fuel to do this. Many of the suggested areas were eliminated on the basis of these studies; the list of candidate sites was pared to five for Apollo 11. When Site 2, in the Sea of Tranquility,* was chosen for the target in the summer of 1969, a waiting world watched and hoped that the space team's confidence was warranted.1

* Site 2 was on the east central part of the moon in southwestern Mare Tranquillitatis. It was about 100 kilometers east of the rim of Crater Sabine and 190 west southwest of Crater Maskelyne - latitude 0 degrees 43' 56" north, longitude 23 degrees 38' 51" east.

1. J. B. Hustler and T. J. Lauroesch, "Final Report, Phase IV: Lunar Photo Study, . . . 30 November 1967-30 November 1968," Eastman Kodak Co. rept., 14 March 1969, pp. iii-v; John R. Sevier, telephone interview, 7 June 1971; Arthur T. Strickland memo, "Apollo Lunar Landing Site Designation," 23 Dec. 1968, with enc., Lee R. Scherer to Apollo Prog. Dir., "Clarification of Nomenclature of Apollo Lunar Landing Sites," 5 Dec. 1968.