Beamed energy propulsion, Lunox, and future exploration of our moon.
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How can our exploration of the moon be efficiently extended to 100% of lunar surface with the aid of Lunar Oxygen Propellant (LUNOX) and Beamed Energy Propulsion?
The original Apollo mission focused on getting lunar rock samples, with very limited scientific program and tests performed right there. The new Constellation mission, to be conducted by NASA, anticipates longer-term scientific experiments on the moon. As a new step comparing to Apollo mission, there will be use of advanced propulsion techniques, thus cryogenic engines will replace hypergolic. In addition, separate launches of spacecraft and crew modules will be substantial departures from Apollo mission. In general, Constellation exploration program will be similar to an Antarctic 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.
Oxygen as beamed-energy-heated monopropellant offers storage advantage compared to hydrogen but has lower exhaust velocity. At chamber temperature of 4000K, LUNOX provides 3000 m/sec (specific impulse of 300 sec) which is comparable to chemical propellants. Hydrogen offers four times increase in exhaust velocity (Isp = 1200 sec) at this temperature.
As beamed power at fixed thrust is proportional to exhaust velocity, the power needed at burnout is reduced by a factor of four for oxygen compared to hydrogen.
Compared to earth-based beamed-energy launches, LUNOX advantage vs. hydrogen in power requirements will 24 = 6 x 4. It will be even better, if we take into account all losses of beamed energy due to earth atmosphere.
In order to launch from the moon to low lunar orbit, the mass of loaded propellant appears a little less than burnout mass. As BEP thruster has simple design, the loaded LUNOX mass will be roughly equal to payload mass. This makes feasible using BEP for launching Lunar Shuttle Vehicle (LSV) with return payload to orbiting command module.
Avoiding the need to carry Lunar Excursion Module for lunar orbit to surface transport (and back) reduces the Earth launch mass by a factor of two. LLO refuel provided by the LSV reduces launch mass by a factor of three.
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.
Article Source: Articlelogy.com
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