NAFAL Drive

The NAFAL Drive or 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).
• They are most famously used by Generation Ships and Sleeper Ships.

Description (Specifications)

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).

NAFAL Drive Specifications

NAFAL Maneuver Drive Specifications (Starship Propulsion)

Category	Specifications	Remarks
Name	Generic Maneuver Drive	Gravitic Thruster
Drive Type	Relativistic Drive NAFAL	Sublight Relativistic space drive.
Velocity	Acceleration = 0.1g / 0.1 c max velocity achieved at engine cut-off Max Accel = 0.9g achieving 0.9 c velocity.
Duration	Limited by reaction mass or fuel tankage.	Time dilation effects may modify.
Hazards	Collision or drive failure	The vacuum is an unfriendly environment for most lifeforms and life support is always potentially failure ridden.
Physical Constraints	Vector limitations	Operable along a focused radial vector from gravity source out to about 1/8 lightyear
Geometry	"~Euclidean" (Riemannian / Geodesic Trajectories)	Conventional space-time
Levels	1 level	Conventional space-time or normal space
Entry	1/8 Lightyear	n/a
Exit	1/8 Lightyear	n/a
Fuel	Power-plant Dependent	Typically radioactives or hydrogen fuel
Resource Requirements	Machinery, fuel, electricity, etc.	Fission power plants and other long-duration power sources are in widespread use. Other plant types also exist.
Inventor
Characteristics	Integral Inertial Dampers/Acceleration Compensation

History & Background (Dossier)

For example, the Long Range Survey Ship 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 1,700 weeks. Time dilation effects at high speed mean the travellers have spent only 1, 680 weeks in travel. The ship then decelerates for 51 weeks and proceeds to explore the nearby system.

Alternatively, the 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=) 1,880 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.

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Library Data Referral Tree

Please refer to the following AAB Library Data for more information:

Starships:

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Speed-of-Travel

• Speed of Travel

• NAFAL (STL) - (Not As Fast As Light) / (Slower Than Light)
• Light Speed (c)
• FTL - (Faster Than Light) - "Superluminal"

• Astronomical Unit (AU)

» Imperial Standard Astronomical Unit

• Light-second (ls)
• Light-minute (lm)
• Light-hour (lh)
• Light-day (ld)
• Light-week (lw)
• Light-year (ly)
• Parsec (pc)

» Solomani Parsec

» Vilani Parsec ("Deshi")

» Imperial Standard Parsec

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Impulse-Drives

• Spacecraft Drives (Interplanetary Drives)

• Reaction Drives:

• Reaction Rockets:

• R-Drive (Rocket Drive)
• O-Drive (Orion Drive)
• P_H-Drive (HEPlaR Drive)

• Impulse Drives:

(Field Propulsion Drives / Propellantless Drives)

• Z-Drive (Lifter / <1.0 D)
• G-Drive (Gravitic Drive / <10.0 D)
• M-Drive (Maneuver Drive/Thruster / <1000.0 D)
• N-Drive (NAFAL Drive / <¹/₈ ly)

• Reactionless Drives:

• T-Drive (Reactionless Motion Thruster):

• Gyroscopic Inertial Thruster (GIT)
• Dean Space-Thruster Drive

• T_N-Drive (Reactionless Field Thruster: Advanced Gravito-Nuclear Impulse Thruster)

• Deep Space Maneuver System - ("Reactionless")

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Interstellar-Drives (Advanced)

• Starship Drives (Interstellar Drives)

• N-Drive (NAFAL Drive / < ¹/₈ ly)
• Jump Space Drives

• Jump Space
• Jump Drive History

• Jump Governor
• Nexus Linkage Device
• Nth Order Jump Space Drives: ("Otherspace Hyperjump Drives")

• J-Drive - Jump Drive (JD₀: "0th" Order Jump Space Drive / > 100 D)
• H-Drive - Hop Drive (HD₁: 1st Order Jump Space Drive / > 1000 D)
• S-Drive - Skip Drive (SD₂: 2nd Order Jump Space Drive / > 10,000 D)
• L-Drive - Leap Drive (LD₃: 3rd Order Jump Space Drive / > 100,000 D)
• B-Drive - Bound Drive (BD₄: 4th Order Jump Space Drive / > 1,000,000 D)
• V-Drive - Vault Drive (VD₅: 5th Order Jump Space Drive / > 10,000,000 D)

• D₆-Drive - "Six Drive" (D₆: 6th Order Jump Space Drive / > 100,000,000 D)
• D₇-Drive - "Seven Drive" (D₇: 7th Order Jump Space Drive / > 1,000,000,000 D)
• D₈-Drive - "Eight Drive" (D₈: 8th Order Jump Space Drive / > 10,000,000,000 D)
• D₉-Drive - "Nine Drive" (D₉: 9th Order Jump Space Drive / > 100,000,000,000 D)

• Jump Potentiator ("Jump Exponentiator")

» Hieronymous Nexus Linkage

• Conjectural Drives

• Jump Potentiator ("Jump Exponentiator")

» Hieronymous Device

• "Inertialess Drives":

» Inertialess Drive ("I_M -Drive")

» Triplanetary Drive ("I_T -Drive")

• Alcubierre Drive ("Albuquerque Drive")
• Improbable Drive
• Reality Drive

• Alternative Interstellar Drive Technologies

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References & Contributors (Sources)

This list of sources was used by the Traveller Wiki Editorial Team and individual contributors to compose this article. Copyrighted material is used under license from Mongoose Publishing or by permission of the author. The page history lists all of the contributions.

• Marc Miller. T5 Core Rules (Far Future Enterprises, 2013), 323-327.
• Marc Miller, Robert Eaglestone, Don McKinney. Starships (Far Future Enterprises, 2019), 55-56, 63, 76-79, 100-109.
• ArXiv.org Facets of Brachistochronic Trajectories
• Planetary Transfer Calculator
• Traveller Wiki Editorial Team
• Author & Contributor: Lord (Marquis) and Master of Sophontology Maksim-Smelchak of the Ministry of Science