[Marasmusine]

In researching spaceship drives, I've found the following tidbids of information.

Liquid Hydrogen = $4.5 per kilogram
Thruster-grade Argon = $40 per kg
Thruster-grade Xenon = $5000 per kg
Liquid Oxygen = $0.08 per kg

Using the GURPS baseline of $2000 for a ton of LH2, converting to GURPS $ gives (2 significant figures):
Argon = $18000 per ton
Xenon = $2200000 per ton
LOX = $36 per ton

The GURPS price for "ionizable reaction mass", realistically, seems to be off by several orders of magnitude. An MPD Arcjet can use hydrogen, though.

Here's some thruster stats:

NEXT Ion Thruster: Impulse 4190, 0.236 N thrust @ 6.9 kW, 58.2 kg
In GURPS: Delta-v of 1.4 mps, thrust 0.0002 G, requires 0.12 MW / ton, uses Xenon

VASMIR Magnetoplasma rocket: Impulse 12000, @ 2.5 MW, 1900 kg; 5 N thrust @ 0.2 MW (estimates from proposed design and the VX-200 prototype)
In GURPS: Delta-v of 4 mps, thrust 0.0016 G, requires 1.3 MW / ton, uses Argon

RD-0410 Nuclear Thermal Engine: Impulse 910, 2000 kg, 35300 N thrust
In GURPS: Delta-v of 0.3 mps, thrust 0.88 G, uses LH2

Vulcain 2: Impulse 429, 1800 kg, thrust 1359000 N
In GURPS: Delta-v of 0.143 mps, thrust 4G, uses LH2/LOX

I'm trying to get thrust-to-weight ratios for MPD Arcjets and the lithium-fueled LiLFA thruster. Also, the cost-per-ton of thruster-grade lithium.

Power
I read about a power unit's "alpha" on Winchell D. Chung's excellent site, and derived these power outputs for a 1.5 ton module in a 30-ton hull (all TL8 I guess)
Radioisotope Thermoelectric Generator = 0.015 MW
Fuel Cell = 0.115 MW
Fission Plant = 0.083 MW
Nuclear Power Unit (design proposed by Otis Peters @ Los Alamos) = 0.1 MW


Do any of the above figures look wrong?