Sunday, August 08, 2010

Lunar Launch Platform

Terra, mother of all humanity, has proven very fertile and will give some of her children a promising send off.

Terra's little sister, Luna, is eager to help and has ample resources.

CONTENT
Thought Experiment (TE) assumes a battleship sized interplanetary vessel which is at least 300,000 metric Tonnes (mTs). It might be feasible to supply perhaps a small portion of that mass (Terran top soil and Terran water) from Earth; however, the vast majority of that mass will be infrastructure and it would be much more effective to get that material from Luna. The mass is readily available and can be more easily exported from Luna due to Moon's lesser gravity and perhaps with support of a Lunar space elevator (smaller version of Terran space elevator).

Lunar Resources

Routine mining operations can recover several useful materials from Moon. Large areas of Lunar surface are covered with regolith to a depth of several meters. This substance is largely composed of materials shown in following chart.
Oxygen from the Moon. Oxygen is necessary for breathing, and it has several other benefits (for example: rocket fuel). Fortunately, oxygen is the most abundant element in lunar soil. Lunar oxygen can be condensed into liquid and stored in tanks made from lunar metals; then, it can be easily launched from the Moon which has much less escape velocity then Earth.
Ice on the Moon. Data from the Lunar Prospector spacecraft indicates water ice at both the north and south lunar poles. This agreed with previous results from the Clementine mission. While this issue is still being investigated, some scientists estimate as much as 6 trillion kg of lunar ice. If one Olympic sized swimming pool contains 3,000 mTs of water, then Luna might have enough water to fill 1,000 such pools. This is a lot of water, but it's tiny compared to Earth's oceans which contains about 1,260,000,000 trillion liters of water. Thus, human's water use on Luna should be restricted to water exported from Terra. (See previous work on exporting water via Space Elevator.)
Energy for Earth. Researchers and space enthusiasts see helium-3 as the perfect fuel: extremely potent, nonpolluting, with virtually no radioactive by-product. While it's rare on Earth, it's relatively plentiful on the moon (1 part per 100 million). It's been proposed to explore the moon, mine lunar regolith for the helium-3, then import to Earth for efficient fusion use.
Though extremely rare on Earth, Helium-3 (He-3) is abundant on the lunar surface. Professor Kulcinski, Director of University of Wisconsin's Fusion Technology Institute, estimates that the Solar wind has deposited over a million metric tonnes of He-3 in the lunar regolith. Since the regolith has been stirred up by collisions with numerous meteorites, He-3 might exist down to several meters below the lunar surface.The highest concentrations are in the lunar maria; about half the He-3 is deposited in the 20% of the lunar surface covered by the maria.

At the University of Arizona's Lunar and Planetary Laboratory, Prof. Tim Swindle and his team have mapped likely lunar helium-3 deposits. They've determined the lunar landscape most exposed to solar wind as locations of mineral deposits that best trap the element.

To efficiently extract He-3, heat the lunar dust to about 800° C. A million tons of lunar soil would yield about 70 tons of He3 gas. "There's enough in the Mare Tranquillitatis alone for several hundred years," says Harrison Schmitt previous astronaut (Apollo 17) and currently a FTI researcher, “Besides the helium, a mining process would produce water and oxygen as useful by-products.”
Filler for TE Spaceship. A mining operation would need to process over 14,000 tons of regolith to obtain one ton of helium-3. Thus, it seems terribly inefficient to simply discard 13,999 tons of carefully processed lunar rocks; why not use this material for structures of interplanetary vessels. If nothing else, it could be used as shielding to protect against extremely high levels of radiation present in outer space.


Lunar Launch

Perhaps Luna's most valuable resource is an excellent launch platform.

New Moon

Once per Lunar cycle, the Moon is between Sol and Earth.
Earth bound observers see a full view of the unilluminated portion of the moon.



Every few years, we see a Solar Eclipse when the New Moon blocks our view of Sol.



New Moon is the best time each month to launch a non-powered vehicle into a solar orbit with slightly less radius then the Terran orbit. According to Newton's universal law of gravitation, this vehicle would have a slightly higher orbital velocity (both angular and linear) then Earth.

Full Moon

When Terra is directly between Sol and Luna, we observe a fully illuminated Moon.
We see a Lunar Eclipse when the Earth's shadow covers the Full Moon.



Full Moon presents the best launch opportunity for a vehicle to accomplish some retrograde progress.



Slightly outside of Terra's Solar orbit, Full Moon's position presents an opportunity for a non-powered vehichle to achieve a solar orbit slightly greater then 1 AU (Earth's orbital radius). This means a slightly slower orbital speed.

All Lunar Phases

Line-of-Sight (LOS).
TE assumes g-force vehicles can go directly from any Lunar position
to any interplanetary position not obstructed by Terra or Sol.

In other words, if the ship's crew can see their destination; they can go directly to it.
Home Berth for TE Spaceship. TE assumes g-force vehicle orbits around Luna when not traveling to/from interplanetary destinations.


As humanity transforms Luna into a more comfortable home, orbiting g-force vehicle can leverage these transformations. A few are listed below.

  • He-3 and Nuclear Reactors. The most critical change will be a source of energy. During the two week long lunar 'day', lunar settlements will get plenty of sunlight from solar mirrors and collectors. However, the settlements will not get any solar power during their 2 week lunar nights. Thus, a primary use of He-3 and their reactors will be to provide power lunar settlements for at least half the time. He-3 energy production will also be needed on g-force vehicles because solar mirrors/collectors are very impractical for a g-force moving vehicle even if it happens to be without practical range of Sol.
  • Earth's Soil for Agriculture. Human settlements on Luna will need a means of food production. Most effective agriculture will use Terran soil with the microbes which make possible the growth of Terran flora; thus, initial Lunar agriculture will need to import several tons of Terran soil to be kept in Lunar "greenhouses". Eventually, the "seed" soil from Earth will spread as carefully selected portions of Lunar material mix with it. In turn, portions of this "terraformed" Lunar soil will need to be launched to the extraterrestrial vehicles so they, in turn, can start their own agricultures. Agriculture will be optional for g-force spaceships (due to relatively short trip duration); however, on-board trees will be a great supplement of breathable oxygen.
  • Water from Earth's Oceans. Luna's native water supply will likely need to be supplemented with Terran oceanic water. After necessary treatment, Lunar settlements will put this additional water to good use. In turn, this water will need to be transhipped to the g-force vehicles for use as fuel, life support, possible buffer against inflight radiation and possibly for recreation.



SUMMARY

Filler for TE Spaceship
One ton of helium-3 requires processing 14,000 tons of lunar regolith. This resource could be used to help build enormous infrastructure of g-force spacecraft.

Home Berth

G-force vehicle orbits around Luna when not traveling to/from interplanetary destinations.

Orbiting g-force vehicle can leverage
Lunar Transformations
  • Energy source: He-3 Reactors.
  • Terran Topsoil
  • Terran Ocean Water

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