Spaceships: Escape to the asteroids

[DataPacRat]

In my 3e hard-science TL9 'New Attica' setting, a potential plot point involves the main characters deciding to escape the coming MAD-level war between the orbitals and Earth, and scooting off to the asteroids to set up a self-sufficient little colony for themselves. I'm currently fiddling with potential ship designs; and I'm using the boardgame "High Frontier" as part of the background reference material for available technology. Using that system (which has a resolution of 40 tons), the current design is:

Rocket: Salt-water Zubrin and radiators. Thrust 8600 kN (~1-1.3 gravities), Isp 8ksec. 160 tons

Fuel: 160 tons
delta-vee: 16 km/sec (~10 mps)

Active/awake crew and life-support: ~20 people, 120 tons

Main Cargo: Robotic prospectors, smaller vehicles, mining gear, factory gear, generator, reactor, radiator: 200 tons

Second cargo: Colonization gear & frozen colonists: 200 tons

Dry mass: 680 tons
Fueled mass: 840 tons



Trying to convert that to GURPS using Spaceships, the closest approximation I've been able to get is:

TL9, Exposed Radiators
SM+8, unstreamlined: 1000 tons

8 Cargo holds: 400 tons capacity
1 Control room: $2M
1 Engine room: $.3M
4 Fuel tanks: $1.2M
3 Habitats: bunkrooms: $3M
1 Habitat: 6 specialized rooms: $1M
1 Open Space (food production): $.1M
1 Reaction engine, fission, Nuclear saltwater: $5M
Spin Gravity: $.1M

Fuel, 200 tons: $20M

Total cost for 1-way trip: $31.7M (plus cost of colonization gear)


Does that look reasonably sane to you? Do you see any places for obvious improvement?