Exploring the Unknown: Selected Documents in ... - The Black Vault

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Project Apollo: Americans to the Moon
Respectfully yours,
John C. Houbolt
Document II-16
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
LANGLEY RESEARCH CENTER
VOLUME 1
MANNED LUNAR-LANDING through use of LUNAR-ORBIT RENDEZVOUS
[i]
FOREWORD
In the course of conducting research on the problem of space ren dezvous
and on various aspects of manned space missions, Langley Research Center has
evolved what is believed to be a particularly appealing scheme for performing
the manned lunar landing mission. The key to the mission is the use of lunar
rendezvous, which greatly reduces the size of the booster needed at the earth.
More definitely the mission may be described essentially as follows: A
manned exploration vehicle is considered on its way to the moon. On approach,
this vehicle is decelerated into a low-altitude circular orbit about the moon. From
this orbit a lunar lander descends to the moon surface, leaving the return vehicle
in orbit. After exploration the lunar lander ascends for rendezvous with the return
vehicle. The return vehicle is then boosted into a return trajectory to the earth,
leaving the lander behind.
The significant advantage brought out by this procedure is the marked
reduction in escape weight required; the reduction is, of course, a direct reflection
of the reduced energy requirements brought about by leaving a sizable mass in
lunar orbit, in this case, the return capsule and return propulsion system.
This report has been prepared by members of the Langley Research Center
to indicate the research that has been conducted, and what a complete manned
lunar landing mission using this system would entail. For further reference, main
contacts are John D. Bird, Arthur W. Vogeley, or John C. Houbolt.