A SPACESHIP TO SATURN

A nuclear electric ship for flight to the outer solar system.  The passenger section is about 30 m by 45m (100 ft. by 150 ft.) and contains counter-rotating centrifgues.  The waste heat radiator is about 50% larger than a footbal field.  The high specific mass (2 kWe/kg.) vapor core reactor, MHD, generators, pumps and radiator amasses 2000 metric tons and generates 4000 MWe.  The rest of the ship amasses 1000 tons.  Alloys of aluminum-lithium, composites and carbon nanotube composites are used to make the ship as light as is possible.

above: drawing by D. Martin based on Dietzler

above: Cargo ship with cargo module and an ET ship with NTR for exploration of Saturn's moons.  This robotic ship will fly by Hohmann minimum energy orbit to Saturn in 6.04 years and be there well ahead of humans to maximize payload to Saturn.

Cylindrical passenger section. Centrifuges rotate at 5 RPM to produce 0.6 G.  Radius 22.5m Superconducting magnetic coil generates a field to reduce galactic cosmic ray influx.

A computer program has been used to make a rough determination of the trajectory to Saturn. To reach Saturn in 251 days, a delta V at departure of 62 kps and another at arrival of 71 kps is necessary. Zero boil-off, cheap magnesium from Luna will serve as propellant. This flight requires very large amounts of energy.  The ship will need about three months to reach top speed and another two months to slow down into orbit around Saturn and that greatly complicates the orbital mechanics of interplanetary flight.  In any case, we can get some rough ideas of how much energy and propellant will be necessary.  Automated cargo ships will fly by minimum energy hohmann orbits many years before humans reach the Saturn system.  Fast manned ships won't have to drag along everything needed for the expedition.  The mission will last many years.  A base will be established on Titan or underground on a smaller moon for protection from cosmic rays.

The minimum total energy is achieved with an exhaust velocity of about 80 kps.  This requires 12,817 tons of magnesium.  With an exhaust velocity of 110 kps,  only 4% more energy (4.26E16 joules vs. 4.1E16j) is needed and only 55% as much propellant-that's 7051 tons of magnesium- two solid cylinders of the metal each about 13m wide and 15m long. That seems like a good compromise.

A modification of the Saturn Ship with VCR-MHD-turbines on the bow and PIT banks (Pulsed Inductive Thrusters) on stern.  Massive waste heat space radiator.  Passengers ride in teardrop shaped hulls with pressurized spheres within and meteor bumpers in fore of teardrops.  These rotate to produce "artificial gravity" and motorized system in hub keeps rest of ship non-rotating with respect to the stars, Sun and ecliptic plane of the solar system.