WtV: Faction Asgard: Ferry Concept

Ferries are the standard workhorses between the different space installations of the Tau Ceti / Valhalla system. Their drive module contains usually two robust small nuclear reactors ( Actually RTGs, which are very primitive but also very reliable ) as power generators.

The extensible spine of a ferry carries an amount of solid fuel rods which are fed from an automated system to the central drive nozzles reaction chamber.
In front of the drive compartment rings of ice gets stacked before a travel, providing water ( for electrolysis - provdes O² for the solid fuel to burn as well as H² to be used in the CO² scrubbers and as fuel for the maneuver thrusters ) as radiation shielding between crew, freight and the reactors.

The Head contains the sensors as well as the navigation equipment, and can , whilst the rest of the ferry rotates to provide artifical gravity to docked habitat modules and the crew compartment, be rotated counterwise to ease navigation by providing a stable point of view.
The dockable containers along the spine can be either habitable modules ( capacity of 4 to 8 persons ), shuttles or freight containers.

Legend:
Orange: Communication, Control and Command
Red: Rotation couplers and airlocks
Yellow: Reactors, Engines, Drive Fuels
Light Gray: Thrusters and main Heatsinks
Green: Habitation module, hydroponics.
Blue: Water tanks and radiation shielding
Dark Gray: Spine and antenna booms
Violets: Attached containers, 80m overall length ( 4x standard containers )

The launch rail that catapults a ferry from a space station or a habitat is a single rail that connects to anchors connected to the spine between the lower two container racks.
To connect to the rail, the forward communication antennas get rotated out of the way by 90°.

Launch rails for crewed flights are usually between 15 and 60km long and provide between half and all of the needed acceleration for the main travel.
Fuel ( both the rods for the main thruster as well as electrolysed Hydrogen and Oxygen for the four secondary thrusters ) is usually only expended for decelleration.
For this, a Ferry locks down and rotates its thruster array to point toward its destination, and then slows down as is needed.