Project Ishtar-class Booster

[zakueins]

The concept, as I worked on it-

• About big enough to fit on a Jupiter 246 or Ares V. So, no wider than about 8m, no heavier (fully loaded) than 160,000 lbs.
• Nuclear engine. Perhaps two versions to test out a nuclear thermal rocket or VASMIR-type setup. Both will be powered by a nuclear reactor (bimodal for the nuclear thermal rocket). "Shadow shield" drive plate between the engines and the rest of the ship.
• Fuel is liquid hydrogen, with the option of liquid oxygen. Fuel tanks are designed to be removed, for refueling and/or using the tanks for volatile storage (i.e. dropping a few on the moon, pumping in liquid oxygen from lunar oxygen production).
• Significant RCS array. Probably just a "vent" thruster system using the main fuel (easier than trying to figure out how to handle fuel and such-an option would be to use a small, integral liquid oxygen tank to the liquid hydrogen tanks for more "proper" thruster).
• Cargo clamps on the front, "side mount" clamps on the side. I could easily see a Mars mission being built of about five Ishtar boosters, using four to get to Mars with a full load of cargo (crew modules, landers, etc), and using the single remaining engine for the return trip.

This gives an idea of what the Ishtar looks like. I'm considering that there is probably a Crew Module that uses something other than the Orion as the "command" module (same size as Ishtar, carrying about 4-6 people with enough space to "live"). I'm thinking of the use of the "large" hatches on the ISS for access to the interior of the ship.

So, anybody want to help me out with this concept?