TABLE4. Steam Rocket Propellant Option
based at HEEO shows the Amount of Water
Needed for Various Combinations of Trip Time,
Crew Cab and ECCV, and Lander Combinations
for Mars Missions.

TABLE5. CRYO FUEL Propulsion Option based at
either Space Station Freedom Orbit or HEEO shows the
Amount of Water Raw Material Needed for Various
Combinations of TripTime, Crew Cab and ECCV, and
Lander Combinations of the Manned Mars Mission.

A 200 MW, 1200 C tanker uses 4384 Mg to deliver the same 500 Mg s. Over the same period this 36.96 KMg
is, again, enough for 7 tankers.

A colder reactor run at high power or a hotter reactor run at low power would result in about 3500 Mg per year
available at HEEO. Of course, this would mean the launch of 7 tankers,.

If good luck happens and we can run a hot reactor at high power, the table shows that an 800 MW tanker run at
1200 C uses 2675 Mg to deliver 500 Mg s. The 36.96 KMg would result in about 5500 Mg delivered to HEEO.

Status Quo

--Standard Mars Mission Scenario and Payloads:Baseline ExPO/JSC

Current NASA plans are to use hydrogen launched to low Earth orbit (LEO) from the Earth for nuclear
thermal rocket propellant in a manned mission to Mars (NASA 1991). The payloads also under consideration for
Mars exploration (at least the first few missions) are as follows:
* 58 Mgcrew habitat system
* 5.8 Mgcrew return vehicle
(ECCV, for Apollo-type Earth reentry)
* 81 MgMars excursion vehicle (MEV)
with storable propellants

Other dry weights not associated with propellant tankage are as follows for the piloted vehicle: