-11-
The validity of this approach was amply demonstrated when a similar
system was carried around the Moon on Apollo missions 15, 16, and 17.
A photogrammetric control net and topographic maps with 15 m horizontal
and vertical accuracy are now being produced for the Moon from these
photographs.
In the NAS proposal the camera systems would be mounted in an un
manned spacecraft, and exposed film would be accumulated in a capsule at
the front of the vehicle. After all film had been expended, the film
capsule would be ejected and recovered by aircraft. This approach was
seriously considered but failed to win final approval. The best hope
for such a system now is an unmanned package to be launched and serviced
by the Shuttle.
It requires no great talent in cost-effectiveness analysis to
determine that a manned mission is a poor way to acquire photographs.
Too many constraints are imposed on spacecraft dimensions, cost, power,
weight, orbit, and lifetime just to keep the crew alive and assure their
return. The photographic coverage patterns achieved by Skylab in a year
of operation are effective documentation of the results obtainable from
a manned mission. Hardly a single standard map sheet at scales compatib l
with the resolution of the photographs was covered with cloud-free pictu r ,
In terms cTf controlling camera operation, an electronic black box can do
everything a man can do--and more--at an infinitesimal part of the cost.
Most assuredly there is a continuing requirement for the low-
resolution repetitive synoptic multispectral data typefied by ERTS-1.
But equally assured is a requirement for high-resolution, photogrammetrical1)
designed photography useful for standard topographic mapping. Undoubtedly
there are severe political problems--much more stringent than the technical
ones--in acquiring high-resolution data from space (14). But unless these
problems are faced and solved, the full benefit of space sensing will
simply not be available to nations of the Earth. What is needed is a
resolve to build and operate systems which are obviously required to
produce the most useful information. More critical than the technical
problems are the organizational and administrative structures that will
permit the information to be acquired and disseminated worldwide without
offending national sensitivities (15).