As rancorous debate rages over the effects of the Obama administration's cancellation of the Constellation program, there is no shortage of plans to attempt to—once again—develop a coherent American space policy.
Two interesting plans have been developed by two very different space visionaries. Paul Spudis, a lunar geologist and advocate for a return to the Moon, has proposed a new architecture for a systematic return to the Moon that employs a number of outside the box thinking. Meanwhile Robert Zubrin has suggested something he calls the "Transorbital Railroad."
Spudis's plan to return to the Moon, developed with Tony Lavoie of NASA's Marshal Spaceflight Center, begins with sending teleoperated robots to the site of a lunar outpost to prospect for and then extract lunar resources, principally water, then cache them for later use..Lunar habitats, power systems, thermal control systems, navigation and communication, along with surface infrastructure such as roads and landing pads made from fusing the lunar soil by microwave would also be built and deployed. In effect, the very first people to return to the Moon, would have a ready-made lunar base with much of the resources they will need to live and work.
The plan also envisions deploying communications and GPS satellites and refueling stations both in Low Earth Orbit and at one or more of the Lagrange Points between the Earth and Moon.
The plan allows for a variety of space vehicles, from commercially available Atlas V, Delta IV, and Falcon 9, to the envisioned shuttle derived heavy lift launcher being developed by NASA. Spudis and Lavoie prefer a side mounted heavy lifter rather than the inline heavy lifter, largely due to lower development costs.
Robert Zubrin, a warm advocate of Mars exploration and colonization, has a plan to open up space that might actually compliment the Spudis/Lavoie plan to return to the Moon.
The "Transorbital Railroad" plan involves NASA buying six heavy lift launchers of 100 metric tons each at $500 million per launch and six medium lift launchers of 20 metric tons each at $100 million each. The combined yearly cost of this program, minus development costs, would be $3.6 billion a year.
NASA would then turn around and sell either a portion or all of each launch at greatly reduced costs. Thus the price to the send cargo into space would be greatly reduced, making space fight more affordable to private entities as well as various government agencies (the military, NOAA, and NASA itself.) The scheme would involve cargo at first, but then be expanded to people in due course.
Zubrin's plan would involve a subsidy for space transportation. He suggests that the plan would allow launch costs to decrease over time, allowing the expansion of launches over time.
One can see NASA using this "Transorbital Railroad" system to launch return to the Moon elements under some variation of the Spudis/Lavoie return to the Moon program.