LUNAR EXPLORATION CONCLUDED

Apollo 15: Great Expectations

Apollo 15, the first of the "J" missions, was the most complex mission yet attempted, one of which much was expected. Its landing site, 26 degrees north of the lunar equator, was the first outside the original " Apollo zone." Commander David R. Scott would bring the lunar module to the surface along a steeper approach path (25 degrees) than had been used previously, coming in over the Apennine front north of the 3,500-meter (11,500-foot) ridge of Hadley Delta. His landing site was about 5 kilometers (3 miles) northwest of Hadley Delta, 11 kilometers (7 miles) southwest of the foot of 5,500-meter (18,000-foot) Mount Hadley, and about a kilometer (half a mile) east of the edge of Hadley Rille.1

Apollo 15 was the first mission to fly the extended lunar module with the increased payload it could carry: expendable supplies sufficient to support the astronauts for 67 hours, a complete lunar surface experiments package [see Appendix 5], and the first lunar roving vehicle. Excursions were planned to the foot of the Apennine Front and along Hadley Rille. In addition to the usual geological investigations, the crew would take core samples to a depth of 2.5 meters (8 feet), using an electrically powered drill. Temperature sensors inserted into the drill holes would enable scientists to record the rate at which heat flowed from the moon's interior to the surface.2

Starting with Apollo 15, the orbiting command and service module had a much larger role to play in the lunar science program. While Scott and LM pilot James Irwin were on the moon, command module pilot Alfred Worden's flight plan called for him to operate a group of instruments carried in the scientific instrument module (SIM) in the service module. Two cameras would collect high-quality photographs of the lunar surface. A laser altimeter was provided to give a precise profile of the lunar surface and to allow photogrammetrists to correct the data from the cameras, from which accurate maps of the moon could be produced. Besides cameras, the SIM bay housed instruments for remote sensing of the lunar surface and a scientific subsatellite to be released in lunar orbit for long-term measurement of particles and magnetic fields. On the trip back to earth Worden would make the first extravehicular sortie in cislunar space to bring film from the cameras back into the command module.3

1. Rocco A. Petrone to Administrator, "Apollo 15 Mission (AS-510)," Prelaunch Mission Operation Report M-933-71-15, July 17, 1971.

2. Ibid.

3. MSC, "Apollo 15, To the Mountains on the Moon," NASA Fact Sheet MSC-04065, n. d. [c. June 1971].