is in the Earth viewing mode and illumination conditions are satisfactory. 
Crew participation will be required to evaluate cloud cover conditions 
so that maximum advantage can be taken from the film load. The camera 
will, of course, be only a small part of the Shuttle payload, and orbit 
parameters will be dictated by the primary payload. Unfortunately all 
early Shuttle flights will be at low inclinations, and the time on 
orbit will be restricted to 5 or 7 days. Payload space has been re- 
quested on Shuttle Mission 9, presently scheduled for August 1980. The 
potential coverage on this mission will be limited by latitudes 28.5° 
north and south. This will provide good coverage of South America, 
Africa, Southeast Asia, and Australia, but very little over the United 
States, Europe, USSR, and China. Later missions will operate at higher 
orbital inclinations, and coverage provided by a mission optimized for 
the United States is shown in Figure 10. 
It is obvious that short lifetime, multipurpose, manned missions are not 
an efficient way to acquire photography from space. There are always 
conflicting requirements on crew time, spacecraft capabilities and 
attitude, and orbital parameters. If the photography from the early 
Sortie missions proves to be as useful as expected, the camera will sub- 
sequently be mounted in a free-flying spacecraft, such as the Multimission 
Modular Spacecraft (MMS) which is specifically designed for launch and 
service by the Shuttle. Polar orbit capability should be available in 
1983 when Shuttle launch facilities are operational at Vandenberg Air 
Force Base on the West Coast. One or two cameras can be mounted in the 
MMS which contains its own power supply, attitude control, and command 
and data handling systems. Spacecraft power would be provided by solar 
arrays. As illustrated in Figure 11, the spacecraft would be placed in 
orbit utilizing the remote manipulating arm on the Shuttle. When the 
film load is expended, the Shuttle will rendezvous with the MMS, bring 
the spacecraft back into the cargo bay where film magazines could be 
exchanged by astronaut extravehicular activity, or automatically by the 
flight support system being developed for the MMS. The spacecraft can 
then be placed back in its own operational orbit. Periodically the 
entire spacecraft could be returned to Earth in the cargo bay for major 
overhaul. Figure 12 shows the type of global coverage pattern which 
would be available from this mode of operation. 
When this system is realized, photogrammetrists will finally have the 
opportunity of compiling 1:50,000-scale topographic maps from space 
photography anywhere in the world. 
March 1978