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

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Project Apollo: Americans to the Moon
And to cost and schedule, it is clear that EOR requires more C-5 vehicles.
Hence, if vehicles are, indeed, the pacing item, the EOR approach is more costly
and, according to NASA schedule, at least five months slower. It also requires more
extensive launch facilities. These conclusions are modified, of course, if a “logistic”
vehicle capable of near simultaneous launching is needed to support LOR.
Lastly, the analysis of payload margins also offered no significant basis
for choice. LOR is a very ingenious idea which has a fundamental advantage in
that the heat shield and re-entry mechanism need not be carried to the lunar
surface. However, it must pay the price of carrying an entire life support system,
communications system, and navigation (for rendezvous) system. The most recent
detailed studies indicate that there is no resultant payload advantage for LOR,
and that there is probably a disadvantage if the landing is made more than a few
degrees from the moon’s equator or the stay time is increased because of the
plane change which is introduced as the moon rotates.
The clearest point which came out is that the comparison on all scores
involved a mission in which two men stayed on the moon a very short time (LOR)
with missions involving three men for longer times. With this background of
experiences gained from studies already made, it should be possible to estimate
the perturbation on the existing estimates if a two-man capsule were employed
for EOR or direct ascent in a very short time, say two to three weeks. It is most
strongly recommended that this be done. If possible, optimum trajectories should
be considered for each mode since there appears to be no need for lunar orbit
in the EOR or Direct modes. It is our guess that EOR will then show a substantial
payload margin, and that it will be possible to employ earth storable propellants
for the lunar liftoff stages.
[4] Our further thinking has converged on the following conclusions:
1. LOR is an extremely ingenious but highly specialized mode which
does not appear to occupy a central role in the development of a
continuing national space program -- at least as compared to orbital
fueling of large vehicles.
2. LOR appears to have the largest number of critical operations which
must be carried out far from the earth after a period of extreme
crew stress.
3. We, therefore, feel that at the present time we would choose the EOR
mode with a two-man capsule. It ought to be possible then to gain a
substantial weight margin.
4. The history of all ICBM systems has been one of upgrading, even
early in their careers. The “official” escape rating of C-5 has already
grown from 68,000 lbs. to 90,000 lbs. Consequently, we would press
efforts to upgrade C-5 in parallel with its present development.
Several possibilities are clearly open. With reasonable success in
upgrading, the same (item 3) two-man capsule might be carried on