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

Exploring the Unknown 583
Rendezvous. The major concern with respect to the Lunar Orbit
Rendezvous arises from the requirement for rendezvous during the return phase
of the mission. The mechanization of rendezvous has been studied in detail, and
the planned configuration provides a redundant rendezvous capability within
the LEM for all equipment failures except those in the main propulsion system.
A similar capability exists in the command module. Hence the rendezvous
maneuver is backed up with essentially a fourfold redundant mechanization. The
duplicate contact, both radar and optical, which can be established between CM
and LEM before launch from the lunar surface and maintained until docking,
assures adequate relative velocity and position information between the two craft.
Although earth tracking will not participate directly in the lunar operation, earthbased
antennas will monitor the maneuvers and will aid in certification of the
ephemeris of the CM lunar orbit. Studies of the rendezvous implementation, and
simulations conducted at NASA centers and industry facilities, have indicated that
the rendezvous maneuver is less difficult than the lunar landing. Specifi cally, the
rendezvous in lunar orbit is no more difficult than rendezvous in earth orbit.
Indeed, the configuration of the LEM may actually make the lunar rendezvous
easier for the astronauts to execute than an earth orbit rendezvous operation
involving two C-5 vehicles.
Summary of Technical Considerations. The summation of these
considerations leads to the conclusion that the conservative approach to the
manned lunar mission dictates the use of a 25% weight margin for any new capsule
design and the use of storable engines in space. This conclusion, in conjunction
with analyses of the several modes, rules out all modes save LOR and 2-man EOR.
After comparison of landing configurations and rendezvous mechanizations, we
conclude that the technical trade-offs distinctly favor the LOR mode.
[5]
Human Factors
A factor in the LOR mode which has been frequently mentioned is the
effect of mission duration and stress on crew performance during the rendezvous
maneuver. Our study of these factors is summarized in Appendix D [not provided],
which concludes that “pilot performance is not a limiting factor for either direct
or lunar orbit rendezvous missions” based on a survey of the applicable literature
and available test data. Another consideration is that the stress which the astronauts
will undergo during both lunar landing and earth re-entry is at least equivalent
to that experienced during rendezvous. The time constants for both re-entry and
landing maneuvers are set by the mission. The time constant for rendezvous is
at the astronaut’s discretion--several orbits may be used to accomplish the actual
docking in an extreme case. Based on these considerations, we conclude that
the human factors implications are not significant for purposes of selecting a
preferred mode.
National Space Capability
Appendix E [not provided] discusses the implications of the mode choice
on National Space Capability. The conclusion is that the only payload requirements