Foreword

Early on the morning of 26 July 1971. the crew of Apollo 15 in the good ship Endeavour with its cargo (the lunar module. Falcon, and Lunar Rover-1) departed Earth-space for the Hadley-Apennine landing site on the Moon.

The expedition had actually begun 20 months previously and required more than 100.000 people to prepare the launch vehicle, prepare the three vehicles, prepare the spacesuits. gather up equipment, provisions, and instruments, and generally plan the three-day exploration of the mountains of the Moon.

Just over ten years had passed since May 1961. when President John F. Kennedy committed the United States to "landing a man on the Moon and returning him safely to Earth". During this period, tw’enty five US manned space missions had been flown (Mercury, Gemini and Apollo) nineteen in Earth orbit, three around the Moon, and three to the lunar surface.

The crew of Apollo 15 was now embarking on the next phase, the first extended scientific exploration of the Moon. NASA termed it "[one of] the most complex and carefully planned expeditions in the history of exploration." Only two more such missions were to follow, then there would be a hiatus lasting several decades, maybe even longer, before humans would onec again set foot on the Moon.

I was the commander of the Apollo 15 mission. Jim Irwin accompanied me down to the lunar surface in Falcon while A1 Worden looked after Endeavour in orbit. The planning and preparation for our mission had been so thorough that there was no doubt in our minds that we really knew "how to fly to the Moon" and to do so in any conceivable situation. But as "we” (all 400.000 people working on the Apollo program) had learned during the many preceding missions, flying to the Moon and returning to Earth (successfully, that is) is very, very difficult. So, just how did we actually plan and prepare for this extraordinary adventure – how was our Apollo to fly to the Moon?

lire Apollo program was implemented through five sequential tasks that evolved during two overlapping phases perhaps the "ABCs" of how to fly to the Moon:

Phase 1

A. Adopt a method by which men could fly to the Moon and return safely.

B. Build the spacecraft and ground facilities to implement the method.

C. Develop the techniques and procedures to accomplish the mission.

D. Select and train the astronaut crews (the vital link between В and C).

Phase 2

E. Upgrade the capabilities of the entire system to maximize the technical and scientific results of the Apollo phase of human lunar exploration.

In 1967 mission planners at NASA introduced an alphabetic nomenclature by which to describe where individual flights fitted into the overall scheme. This started at "A" with unmanned tests of the Saturn V launch vehicle and worked through a scries of missions of progressively greater operational capability, finally reaching "G", which was the Apollo 11 lunar landing, and "П" lor a number of follow-on missions. These constituted Phase 1. Missions flown during Phase 2 were intended to maximize the science objectives, and were designated "J“. Apollo 15 was the first such mission.