As Dee and her nakama build a colony for themselves in the asteroids, they find a need for a workhorse vessel - and design a class of spaceship which fills all their needs, and then some.
The inital model used for the first trips, the SF-0 "Zip", had a somewhat different drive configuration than became standard. Once it was rebuilt with the new manufacturing processes available on the V-type asteroids, it was redesignated the SF-1 "Love". The next ships sharing the design were the SF-2 "Unity", SF-3 "Imagination", SF-4 "Napier", SF-5 "Ludolph", and SF-6 "Euler". Most official markings are English written in the Unifon script.
Crew: 8 Dry Mass: 135 tonnes Typical fuel mass: 240 tonnes Rated cargo mass: 440 tonnes Main thruster (antiproton-catalyzed n-6Li Microfission): Standard Duty Cycle: ~700 hours thrust per year (8%) Max delta-vee per year: 150 km/sec Propellant used per year: 200 tonnes of water Force: 12.8 kN Acceleration, full tanks and full cargo: 0.0016 gravities Acceleration, full tanks: 0.0035 gravities Acceleration, empty tanks: 0.0075 gravities Isp: 48,000 seconds Exhaust Velocity: 480 km/sec High-Thrust Duty Cycle: ~450 hours thrust per year (5%) Max delta-vee per year: 180 km/sec Propellant used per year: 244 tonnes of water Force: 25.6 kN
From left to right: Non-aerodynamic lander; containerized cargo; small heat radiators for hab section; main comm antenna; a pair of counter-rotating sections, each with three inflatable habitat modules; the main boom and radiators, with tanks for water-propellant inside the boom; and the main drive.
