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Our exploration of the moon requires new ideas of space transportation. This article is about Lunar Oxygen Propellant (LUNOX) and how Beamed Energy Propulsion based on LUNOX will allow us to explore full lunar surface.

The main focus of Apollo mission was sampling lunar surface, while any in situ experiments were very limited. Todays NASA Constellation mission to the moon will be similar to Apollo, although the duration of experiments at the lunar surface will be substantially longer. There is also a significant departure from Apollo scenario: the crew unit and main spacecraft will be launched separately, and advanced cryogenic propulsion systems will be used instead of hypergolic. Leaving aside the specifics of space transportation, by its character the Constellation lunar mission will be a step toward Antarctic-style expedition.

The experience of our exploration of Antarctica will serve as a role model for development of our new frontier: the moon. In this case the major limitation comes from the cost of transportation to and from our natural space satellite. Moving certain life-supporting facilities to the moon will be the key step in cutting the transportation costs. Oxygen is one of the most abundant elements of lunar soil. It can be converted into propellant for earthbound transport.

Unlike Earth, the moon has no atmosphere and its gravity is 6 times smaller. As a result, the major difficulties of energy-beamed launches from earth (atmospheric beam absorption and scattering, air drag, need for larger accelerations, etc.) are much less pronounced or absent on the moon. Water, a natural source of hydrogen propellant on the moon can be found mostly in polar areas. However, water recovery for exploration of non-polar regions is too expensive. In contrast, LUNOX is available from full lunar surface, and hence, used with BEP it can extend our missions to all lunar locations.

When heated with beamed energy, oxygen can be used as a monopropellant. It will have storage advantage over hydrogen, while hydrogen will have much higher exhaust velocities. When heated to 4,000K, hydrogen provides an exhaust velocity of 12,000 m/s, four times faster than oxygen. BEP with oxygen will have exhaust velocities similar to modern chemical propulsion.

At four times reduced exhaust velocity oxygen propellant will consume four times less beamed power in order to generate the same thrust as hydrogen propellant.

Comparing hydrogen BEP on earth with oxygen BEP on moon, oxygen power requirements will reduce by 4 times! Indeed, taking into account difference in gravity we will get factor of 4 x 6 = 24. It will be even better if we recall that BEP on moon has no losses due to atmosphere (in view of its absence).

For lunar surface launch to LLO (low lunar orbit) the loaded propellant mass is slightly less than burnout mass. Due to simplicity of BEP thruster, the payload mass ratio is high and the loaded LUNOX mass is roughly equal to payload mass. Lunar Shuttle Vehicle (LSV), carrying earth return payload to Apollo-type command module, is thereby possible.

Provision of landing and return service by lunar-based LSV reduces mission launch mass by a factor of two. If, in addition, LSV will provide refueling on lunar orbit, the initial launch mass can be reduced three times!

Lets summarize. New exploration of the moon will be conducted in Antarctic-style: year-round deployment, stationary base. Combined with in situ development of LUNOX and use of Beamed-Energy Propulsion (BEP), such exploration can be expanded to all lunar surface, and not only polar regions. BEP is more efficient comparing to chemical propulsion due to high cost of delivery or production of fuel to/on lunar sites. The beaming sources near wavelength of 1 millimeter and power 0.1 - 2 MW are available and can be used for lunar surface to LLO launches.