Launcher Option 4: Space Shuttle and Proton

Another alternative is to use a Proton to launch the fuel, creating the lowest-cost option which includes the Space Shuttle. It saves $340 M over the two Shuttle baseline plan, with the Proton costing only $60 M (varies with exchange rates). The Proton is cheap, can carry cryogenic fuels, has sufficient lift capacity that a third launch is not needed, and has the wonderful feature of launch-on-demand.

Unfortunately, the Proton's cargo bay is too small for a SPACEHAB module to fit, which is the primary pressure vessel for the Artemis Project vehicles. This leaves only the fuel, equipment, and service modules to go in the Proton, and there may be a problem fitting the Lunar Habitat and Lunar Transfer Vehicle both in a single Shuttle flight. In addition, there are considerable logistical problems involved in trucking equipment to Russia, although the pressure vessels can stay in the US, where they will likely be manufactured. Also, there is the issue of either launching the Proton from a low-inclination site, or the reduced payload due to a needed change of orbital inclination.

The Proton has a payload of 53,000 lbs (24,000 kg), and the Space Shuttle has a payload of 55,000 lbs (25,000 kg), which may be upgraded to 62,000 lbs (28,000 kg). This makes for a total capacity of 108,000 - 115,000 lbs (49,000 - 52,000 kg). This is also a tight, but probably adequate, payload limit.

Since the Proton costs so little, it may make sense to purchase a second launch. It would greatly enhance the capabilities of the lunar base if there was so much mass to use for equipment.

Launcher	Payload	Cost
Shuttle + Proton	108,000 lbs (49,000 kg)	$460 M
Shuttle (upgrade) + Proton	115,000 lbs (52,000 kg)	$460 M
Shuttle + 2 Protons	161,000 lbs (73,000 kg)	$520 M
Shuttle + upgrade + 2 Protons	168,000 lbs (76,000 kg)	$520 M

Although the Proton's small payload envelope and logistical problems are a handicap, its low price and lack of a need for a third launch make the Proton a good choice if the Shuttle is to be used.