NAFAL Drive
Not As Fast As Light (NAFAL) Drives are energy-efficient gravity-based interstellar drives suitable for long-term acceleration to near-light speeds. N-Drives are manufactured with performance levels from 0.1G to 0.9G (drive potential 1 for NAFAL = 0.1G).
See also:
Description
A ship operating with NAFAL accelerates to a fraction of light-speed and travels to a nearby star system. The N-Drive operates on the same general gravity manipulation principles as the G-Drive and M-Drive.
NAFAL can only accelerate within about one-eighth light-year (or about 51 weeks of acceleration) of a gravity source. It can similarly decelerate only within the one-eighth light year distance (also about 51 weeks).
For example, Long Range Survey Pride of Yothola with NAFAL-1 Drive accelerates within its home system for 51 weeks at 0.1G. At that point, it is traveling at 0.1C. It crosses the one-parsec (3.26 light years) to its neighbor star in 1700 weeks. Time dilation effects at high speed mean the travellers have spent only 1680 weeks in travel. The ship then decelerates for 51 weeks and proceeds to explore the nearby system.
For example, Colony Ship Nirst with NAFAL-9 Drive can achieve 90% of light speed. Aimed at a system 10 parsecs distant, it accelerates for a year (51 weeks or so) within the home system, at which time it is at 0.9C. The Nirst travels the ten parsecs in (10 x 188=) 1880 weeks. Within the new system the ship decelerates for 51 weeks to investigate the newfound mainworld. The voyage of 10 parsecs (32 lightyears) endures for (51+51+1880 weeks =) about 38 years. The time dilation effects of 0.9C mean that the ship’s travelers experience only about half that time (51+51+820 weeks=) about 18 years.
References and contributors
- Marc Miller. T5 Core Rules (Far Future Enterprises, 2013), 323-327.