Lunar_Deficiency

The Lunar Deficiency Myth

The Moon is called "deficient" by some; a dull rock. It is actually rich in oxygen, silicon, iron, calcium, aluminum, magnesium, titanium, and has some manganese, chromium and sodium. There may be asteroid impact craters with respectable deposits of nickel, platinum group metals, copper and other elements. There are about 40 ppm hydrogen, 100 ppm nitrogen, 200 ppm carbon, 500+ ppm sulfur, 25 ppm helium 4 and traces of helium 3. Helium 3 will really give value to the Moon when fusion reactors that can burn the stuff are developed.

While lunar materials can be used to build solar power satellites, helium 3 fusion will not require covering large areas of land with receiving antennas, power from fusion reactors can be used to generate A.C. while SPS power must be inverted to A.C., and waste heat from fusion reactors can be used to warm nothern cities and temperate zone cities in the winter time. Waste heat from fusion reactors can also be used to desalinate sea water for irrigation. Helium 3 fusion reactors do not need corrosive liquid lithium jackets to breed tritium and are thus simpler than deuterium+tritium burning reactors. The problem is that burning deuterium+helium 3 or helium 3 + helium 3 is much more difficult than burning DT but this might be overcome by laser fusion reactors in the future rather than magnetic containment reactors with their complex and expensive superconducting coils. The International Thermonucler Experimental Reactor which will cost $10 billion is expected to be finished by 2020 CE but it will be years, possibly decades later before an economical power generating reactor is developed.

The economics of fusion power are unknown at this time. Advanced fission reactors like pressurized water reactors, gas cooled pebble bed reactors and possibly breeder reactors; wind power, solar power, biofuels from energy crops and biogas from trash and sewage fermentation, conservation technologies like heat pumps, hybrid cars, better insulated buildings; and remaining reserves of oil and gas as well as clean coal burning power plants will bridge the gap between the present and the time of fusion and space solar power. When a market for helium 3 from the Moon worth several million dollars per kilogram, or several billion dollars per ton, exists it will be worthwhile financially to export elements that the Moon lacks from the Earth, especially when low cost access to space exists thanks to mass production of rockets, fuel efficient ion drive tugs for transport from LEO to LLO, and the use of lunar polar water ice to fuel lunar landers or landers powered by lunar aluminum and LOX and possibly even space elevators made of carbon nanotube fiber from EM L1 and EM L2 and from GEO for cargo and even fusion rocket drives for transit from LEO to LLO or a Lagrange region station. The development of laser fusion reactors should be followed soon by laser fusion rocket drives. So the value of the Moon is immense and there is no need to be miserly about exports to the Moon when helium 3 is mined. No nation on Earth is totally independent. All nations must import what they lack. Eventually there will even be AI robotic asteroid mining and possibly even imports from Mars to the Moon when the space economy grows.

The Moon is plentiful when it comes to oxygen, cast basalt, iron, aluminum clad calcium long distance power lines (calcium is a better conductor than copper), glass for windows and bricks, calcium oxide for cement ( glass and cement will be of use in underground habitations), silicon for solar panels, aluminum for rocket fuel, magnesium for various items, aluminum+magnesium alloys, solar energy and an environment where nuclear fission can be used without danger. Uranium and thorium for fission reactors can come from KREEP along with potassium and phosphorus for agriculture in underground chambers and lava tubes illuminated by fiber optics and sulfur lamps and rare earth elements for many purposes. Rare earth elements like lanthanum, europium and cerium from KREEP might substitute for other elements used in the doping of semiconductors, lasers, alloying, as catalysts, etc. Research into this is called for.

It is possible that in addition to robotic mining, mineral refining and manufacturing on the Moon a substantial human presence can be maintained there someday and even tourism. This is the dream of lunar enthusiasts.

The Moon's greatest "deficiency" is in light elements like hydrogen, carbon and nitrogen. These are needed for plastics, fiber optic cables, seals, gaskets, chemicals, etc. While most products on the Moon can be made from glass, ceramics and metals, there will be some cases where synthetic materials are absolutely necessary. One of these cases is the production of polymers for fiber optic cables. Pure silica glass fibers are not very good and are too expensive. Lunar outposts and towns can link by communication stations at Lagrange points and even some microwave tower links atop mountains and crater rims, but connecting the Moon will require fiber optic cables. In the process of roasting out 25 tons of helium 3 per year, enough to power the USA for a year, from 2.5 billion tons of regolith mined from 2500 square kilometers of lunar surface, about 150,000 acres, Moon miners could obtain one hundred thousand tons of hydrogen, 250,000 tons of nitrogen, 500,000 tons of carbon and 1.25 million tons of sulfur. This would require 100% recovery. Even at a low 50% recovery substantial quantities of these light elements would be harvested. More than enough sulfur for sulfuric acid will be obtained. More hydrogen can come from lunar polar ice in shadowed craters. With these huge quanities of hydrogen water could be made and carefully recycled.

Hydrogen, carbon and nitrogen can be used to make polymers. Looks like we can make many thousands of tons of polymers every year to provide material for making those fiber optic cables. Plastics will also be of use for wiring insulation. Wires could also be insulated with woven glass fiber cloth, but some situations will require plastic insulation. Combining hydrogen, carbon, nitrogen, oxygen and silicon will allow us to make substantial stocks of silicones. We will be able to make larger masses of silicones than plastics made from hydrogen, carbon and nitrogen alone. Silicone rubber seals and gaskets and silicone oil lubricants for machines as well as silicone wire insulation are superior to plain old hydrocarbon plastics and lubricants. I'm not talking about precise analogs for hydrocarbon plastics; I am talking about entirely different materials of superior quality. Given the higher atomic mass of silicon and oxygen than hydrogen, carbon and nitrogen, much of the mass of silicones is due to these elements. Manufacturing silicones will allow use to make larger masses of product than mere polyethylene for instance that consists only of hydrogen and carbon. These silicones may be more expensive than cheap common plastics used on Earth, but their value on the Moon will be great, especially when importation is so expensive.
That's not to say there will be no imports. There will only be imports when no lunar materials suffice or are not available in great enough quantity. We cannot expect cheap plastic wrap or kitchenware on the Moon, but glass jars with metal lids, stoneware, ceramics, iron skillets, aluminum cook ware, low carbon steel cutlery and such will be used. Even so, from 50,000 tons of hydrogen and 200,000 tons of carbon we can make a quarter of a million tons of polyethylene! That's a lot of cheap plastic for a lunar population of a few thousand to a few million temporary tourist residents.

All waste materials containing food residue, paper waste, and plastics will be carefully recycled so once a stock of these materials is produced it will be used over and over again. After years and decades of helium 3 mining some massive stocks of materials made from light elements will exist and be recycled. On Earth we continually pump up oil, make synthetics and thrown them away. If we recycled all the tires, synthetic fibers, motor oil, plastic wrap, toys, latex paint scrappings, and other plastic items from old vinyl to ink cartridges produced in huge quantities, and had a source of cheap energy to run the recycling mills other than fossil fuel combustion, we would not have to use nearly as much petroleum. About a fourth of all petroleum is used to make synthetics! The rest is burned for energy, mostly auto fuel and some electrical power production. Vast amounts of petrochemicals reside in Earth's tire heaps and trash dumps! That's a resouce we will have to tap when oil supplies dwindle in the future. As for mining carbonaceous asteroids in space for kerogen and shipping this to Earth; that would be absurd. There is believed to be hundreds of times as much kerogen in the Earth as petroleum and this will have value someday if we mine for it. Coal will also provide carbon and be combined with hydrogen from water to make synthetics on Earth when we have a cheap abundant supply of electricity from fusion, SPS, and other energy sources.

Helium 3 fusion which will not result in radioactive waste and space solar power will not demand covering huge areas of land with solar panels as ground based solar would and space energy can supply power 24/7 unlike ground based solar. There will be no pollutants spewed into the biosphere. With commercial fusion achieved, and fusion rocket propulsion shortly thereafter, it will become possible to send high speed ships to Saturn, Uranus and Neptune to mine helium 3 from these planet's atmospheres and supply energy to Earth for millions of years. Spaceship propulsion demands enormous quantities of energy and subsequently will demand lots of helium 3.* The use of cycling stations between Earth, Moon and Mars along with solar powered mag-sails that can adjust the orbits of cycling stations to stay in harmony with the changing positions of the planets and solar powered mass beams or microwave beams to corrrect the courses of interplanetary and interlunar cycling stations will not place any demand on valuable helium 3 resources nor will these cycling stations require any rocket propellant aboard the ships. Although enough helium 3 exists in the gas giant planet's atmospheres to power human civilization for millions, perhaps billions, of years, we will only be able to produce so much of the stuff and it will not be wise to strain that production to propell space ships when other propulsion systems exist. Even high speed interplanetary beam riders propelled by mass beams (mass can come from captured comets) or laser-microwave sails could exist to supplant the cycling stations that convey huge numbers of tourists and colonists between Earth, the Moon and Mars; even out to the asteroid belt. Mining expeditions to the outer solar system could use fusion rockets and remain profitable. It might be possible to propell ships to the outer solar system with solar powered mass or laser beams where they brake using fusion. The ships could use fusion to return to the inner system with their valuable loads of helium 3 and brake with mag-sails to economize. Space colonies in solar orbit would use abundant solar energy for power instead of helium 3. Mars is farther from the Sun and only receives 43% as much solar energy as Earth, but SPSs built in Mars orbit could use huge aluminum foil reflectors to increase power output. On Mars, waste heat from fusion reactors will be of great value year round until the planet is terraformed and warmed up. Even then, Mars might be a much colder world than Earth and martians will value that heat. Cities on Mars might be built deep underground to get warmth from the planet's core. Geothermal energy on Earth might have much use in the future also. As tunnels are bored into Mars, and the Moon, for global subway systems protected from space radiation and temperature extremes, the tailings can be used for surface constructions. Mineral deposits of all sorts might be discovered during tunneling. Chromite sinks to deep layers in lava fields and deposits of this chromium ore might be found on the Moon during tunneling. Chromium is used for stainless steel and when doped into aluminum oxide it makes ruby. Perhaps giant ruby rods for lasers could be grown in microgravity space factories someday. These lasers would require heavy cooling systems and might be used for laser fusion reactors, defensive systems and tunnel boring.

* about helium 3 demand for space ships

From Dr. Zubrin's book Entering Space, pg. 88 we find that one kilogram of helium 3 burned in a 60% efficient MHD system could yield 100 million kW-hours of electricty. That's 3.6E14 or 360 trillion joules. From the Artemis Data Book we find that one kilogram of he3 burned with 0.67 kilos of deuterium yeilds 19 megawatt years or 1.66E11 watt hours, the same as 166 million kW hours which would yield 100 million kW-hrs. from a 60% efficient conversion system.

So let's say we have a 60% efficient fusion rocket drive and we want to propell a 1000 ton ship up to 50 kps and reach Uranus in roughly a year. We will need:

0.5(1,000,000 kg.)(50,000 m/s)^2 = 1.25E15 joules!

We will need about 3.5 kilos of helium 3 worth $3 million to $6 million a kilo or $10.5 million to $21 million worth of the stuff. We will also have to brake upon reaching Uranus and use fusion drives to return to Earth where we could brake with mag-sails for efficiency.

A 1000 tons ship is not that huge. We might see 10,000 ton liners in the future. If we are to have hundreds, even thousands of high speed interplanetary flights between Earth, Mars, the Moon, perhaps Venus and Mercury, solar orbital space colonies, main belt asteroids and some of the outer planets too, we can see that substantial tonnages of helium 3 would be necessary at a great cost. If we want to hot rod around the solar system with average delta Vs per flight of 50 kps, fast enough to get us to Mars in a matter of weeks, in 10,000 ton carbon composite spaceships equivalent to 60,000 ton steel ships ( carbon composites 0.050 lb./cubic in; aluminum 0.10 lb./cu. in.; steel 0.30 lb./cu. in.) and we want to see 1,000 voyages a year and a few million space travelers, then we need:

3.5kilos * 10 * 1,000 = 35,000 kilos or 35 tons of helium 3 worth $105 billion to $210 billion!
That's enough to generate 3.5 trillion kilowatt hours with a 60% efficient conversion system. The USA used about 28 trillion kW hours altogether in all forms of energy and about 10 trillion kW-hrs. in electricty alone in 2000 CE. If we start talking about even larger and/or faster space liners and more flights per year for a vibrant interplanetary travel industry of the future then we could use up enough helium 3 to power the world's richest nation for a year every year! Although there are vast supplies of helium 3 in the atmospheres of the outer planets, mining the stuff will require a large investment.

We can see that producing helium 3 for routine interplanetary flight could even someday be comparable to producing enough to power the world when large numbers of cities emerge on the Moon, Mars and other worlds of the solar system and lots of solar and planet orbiting space colonies too! So the use of cycling stations and solar powered interplanetary beam riders makes sense from an economic standpoint. Interplanetary cargo ships could use mag-sails to ride the solar wind. Small couriers and VIP ships like the President's Space Ship One could use fusion power for rapid interplanetary transit. Cyclers will use mag-sails and the solar wind to adjust their orbits as well as solar sails that can be rolled up and unfurled as needed and catch some sunlight for tweaking trajectories without recharging the mag-sail. The solar sails could also get thrust from solar powered microwave beaming stations at Lagrange points in solar orbit. Nuclear powered ion drives might also be used to adjust cycler orbits, but it might be worthwhile to sacrifice a little helium 3 for small fusion thrusters on cyclers that are far more efficient and have higher specific impulses than NEP systems. Finally, cyclers can make use of gravity assists. Taxis will use substantial amounts of propellant. At first, they might use lunar aluminum and LOX. When Mars is colonized and ice mining goes on there and mass drivers are built on top of the great shield volcanoes LH2 and LOX will become available. Robotic miners of carbonaceous asteroids and old short period comets could also supply LH2 and LOX as well as organic chemicals. Some taxis might use NTR and LH2 or LANTR-LOX Augmented Nuclear Thermal Propulsion to rendesvouz with cyclers flying by planets. High thrust like that which can be obtained from LH2/LOX; LH2/NTR; and LANTR is desirable for taxis so that jaunts to and from cyclers are not very time consuming.

For an interstellar flight in a 10,000 ton ship at 0.05c, a rather small and slow moving star ship, we would need:

0.5(10,000,000 kg.)(15,000,000 m/s)^2 = 1.125E21 joules

With a 60% efficient drive we'd need 3125 tons of helium 3 or enough to generate 312.5 trillion kW-hrs. That's enough to power the USA at its 2000 CE rate of consumption for eleven years! So interstellar flight with fusion drives would really put a strain on the helium 3 miners, especially when we look at arks in the 100,000 to 1,000,000 tons range at 10% light speed and faster. Makes a case for solar powered mass beam propelled mag-sailing star ships.

It can also be said that with replicating AI robots we could build all the helium 3 mining infrastructure we need and meet the demand for high speed fusion space liners to convey the masses of humanity between the planets. Economic factors will utlimately decide what kinds of ships and propulsion systems are actually used in the future. The fast fusion liner does have time in its favor because it can make more trips every year than a cycling station can. It can also travel from planetary orbit to planetary orbit without the need for taxis. That will be more convenient. Even with fusion, some LH2 for reaction mass will also be needed, but probably not much more than would be needed for chemically propelled or nuclear thermal propelled taxis.

As Yogi Berra said, "It's hard to make predictions, especially about the future."