THE MILKY WAY GALAXY

	The Milky Way galaxy would seem, by any scheme of mapping, to be 
a record-keeping nightmare created to thwart all who would attempt to 
traverse it. Not only is the entire mass rotating, but it is doing so at different 
rates, from its core to the outer spiral arms. Over time, even small-scale 
structures change enough to be a problem in navigation and mapping. A 
common frame of reference is necessary, however, in order to conduct 
exploration, establish trade routes, and perform various other Starfleet 
operations, from colony transfers to rescue missions.

	Celestial objects become known by planetary deepspace instrument 
scans and starship surveys, and are recorded with StarfleetÕs central 
galactic condition database. Locations and proper motions of all major stars, 
nebulae, dust clouds, and other stable natural objects are stored and 
distributed throughout the Federation. New objects are catalogued as they 
are encountered, and updated databases are regularly transmitted by 
subspace radio to Starfleet and allied Federation vessels.

	During stops at Federation outposts and starbases, all detailed 
recordings of a shipÕs previous flight time are downloaded and sent on to 
Starfleet. Most of the information in the database concerns the present 
condition of an object, with ÒpresentÓ defined as real clock time measured at 
Starfleet Headquarters, San Francisco, Earth. The overall visual appearance 
of the galaxy from Earth or any planet is, of course, unreliable due to the 
limitation of the speed of light; so many additional sources (such as faster 
subspace readings) are needed to keep the database current. Where 
realtime object information is unavailable, predicted conditions are listed.

	The main computers of the USS Enterprise apply the galactic 
condition database to the task of plotting flight paths between points in the 
galaxy. Objects lying along the flight path, such as stellar systems or random 
large solid bodies, are avoided. At sublight as well as warp velocities, the 
external and internal sensors communicate with the computers and engine 
systems to perform constantly updated course corrections along the basic 
trajectory.  Æ