6.2 Relativistic Considerations

While the Galaxy class starship is the most advanced space vehicle in Starfleet's inventory, it is perhaps ironic that one of its most sophisticated systems can actually cause a number of annoying problems with extended use.

As fledgling journeys were made by fusion starships late in the twenty-first century, theoretical calculations concerning the tau factor, or time dilation effect encountered at appreciable fractions of lightspeed, rapidly crossed over into reality. Time aboard a spacecraft at relativistic velocities slowed according to the "twin paradox." During the last of the long voyages, many more years had passed back on Earth, and the time differences proved little more than curiosities as mission news was relayed back to Earth and global developments were broadcast to the distant travelers. Numerous other spacefaring cultures have echoed these experiences, leading to the present navigation and communication standards within the Federation.

Today, such time differences can interfere with the requirement for close synchronization with Starfleet Command as well as overall Federation timekeeping schemes. Any extended flight at high relativistic speeds can place mission objectives in jeopardy. At times when warp propulsion is not available, impulse flight may be unavoidable, but will require lengthy recalibration of onboard computer clock systems even if contact is maintained with Starfleet navigation beacons. It is for this reason that normal impulse operations are limited to a velocity of 0.25c.

Efficiency ratings for impulse and warp engines determine which flight modes will best accomplish mission objectives. Current impulse engine configurations achieve efficiencies approaching 85% when velocities are limited to 0.5c. Current warp engine efficiency, on the other hand, falls off dramatically when the engine is asked to maintain an asymmetrical peristaltic subspace field below lightspeed or an integral warp factor (See: 5.1). It is generally accepted that careful mission planning of warp and impulse flight segments, in conjunction with computer recommendations, will minimize normal clock adjustments. In emergency and combat operations, major readjustments are dealt with according to the specifics of the situation, usually after action levels are reduced.