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DESTINATION MOON: A History of the
Lunar Orbiter Program
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- CHAPTER IX: MISSIONS I, II, III:
APOLLO SITE SEARCH AND VERIFICATION
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- Preparations for the First
Launch
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- [225] NASA launched
five Lunar Orbiter spacecraft to the Moon between August 1966 and
August 1967, and all five successfully performed their missions.
This record set a precedent in the Office of Space Science and
Applications in lunar exploration. Not every Orbiter proved an
unqualified success, but each one obtained valuable photographic
data that subsequently aided the Apollo Program in site selection
for the manned lunar landings of Astronauts Neil A. Armstrong and
Edwin E. Aldrin, Jr. (Apollo
11, July 20, 1969); Charles Conrad,
Jr., and Alan L. Bean (Apollo
12, November 19, 1969); and later
missions. Moreover, Lunar Orbiter photos enabled Surveyor Program
personnel to verify landing sites and to place Surveyors in highly
significant areas on the Moon's surface to perform their
missions.
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- One major reason for the impressive record
of five successful missions was the philosophy motivating the many
individuals in the program. The men who had spent long months of
preparation and training for the Lunar Orbiter flights had
developed emergency procedures for many nonstandard situations
which might arise. It was, however,
obviously impossible to anticipate
or simulate all possible failure modes in these training
exercises, and only a [226] limited set of
contingencies were practiced. The experience gained from these
sessions proved invaluable in detecting and eliminating "bugs" in
the operational systems, improving detection and correction of
potential catastrophes during a mission and the probability of
squelching problems in their embryonic stages.1
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- NASA and Boeing had designed Lunar Orbiter
to be "tweaked." It was not launched and sent on its way to the
Moon and then left alone to perform its mission automatically and
expire. On the contrary, it was designed to operate with the
assistance of ground controllers to overcome risks in each
mission, potential failures in subsystems, and the external
hazards of space. Built to function for a thirty-day minimum
lifetime and an extended period of operation after the termination
of the photographic mission, each of the five Lunar Orbiters
proved successful in fulfilling its mission assignments.
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- The missions, in addition, proved the
usefulness of the orbiter concept in unmanned lunar and planetary
exploration. Lunar Orbiter-unlike Ranger, which was designed to
send back television pictures of the Moon as it raced toward a
terminal impact point on its surface-had the greater
[227]
advantage of orbiting its target for an extended period. Ground
control operators thus had time to analyze any problems which
arose and to prepare commands to the spacecraft to solve each
problem.2 Although risk was a constant companion, the Lunar
Orbiters had a new dimension of flexibility once they were in
orbit around the Moon. The greatly extended time of an orbiting
mission over an impact mission allowed flight operations personnel
the luxury of compensation if a command was wrong or sent at the
wrong time.
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- Twenty-eight months of industrious work
and planning since the time when NASA Administrator James E. Webb
had officially approved the program brought all activities to the
eve of the first launch. During the months from April to August
1966 Langley and Boeing completed the final tasks which preceded
the launch. On July 25 program officials conducted the Flight
Readiness Review at Cape Kennedy, and on July 26 Langley accepted
the spacecraft from Boeing, certified ready for
launch.3
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