VASIMR plasma drive in GURPS...

Anthony · 06-24-2009, 05:25 PM

All drives are subject to a basic limit: (thrust)*(exhaust velocity) cannot exceed 2 * (drive power). Electric drives are generally limited by the power density of electric power sources, which will generally give an overall power density not exceeding 1 kW/kg and probably substantially lower (1 EP in spaceships appears to be around 50W/kg).

Using that figure, ISp per fuel tank of a 1 EP drive will not exceed 0.00031mps/(acceleration per drive). That limits an ion drive (1 EP, 0.0005G) to 0.62 mps/tank, probably indicating that thrust for electric drives should be errata'd down by a factor of 10 (non-electric thrusters can have orders of magnitude higher power).

06-24-2009, 05:25 PM	#9
Anthony Join Date: Feb 2005 Location: Berkeley, CA	Re: VASIMR plasma drive in GURPS... All drives are subject to a basic limit: (thrust)(exhaust velocity) cannot exceed 2 (drive power). Electric drives are generally limited by the power density of electric power sources, which will generally give an overall power density not exceeding 1 kW/kg and probably substantially lower (1 EP in spaceships appears to be around 50W/kg). Using that figure, ISp per fuel tank of a 1 EP drive will not exceed 0.00031mps/(acceleration per drive). That limits an ion drive (1 EP, 0.0005G) to 0.62 mps/tank, probably indicating that thrust for electric drives should be errata'd down by a factor of 10 (non-electric thrusters can have orders of magnitude higher power).