CATS

                                                           CHEAP ACCESS TO SPACE
                                                                        by Dave Dietzler, 2007

     The space elevator is the cherished dream of the future for cheap access to and from space, but such a structure is centuries away although experiments with filaments dangled from GEO may be conducted in a few decades depending on how fast C60 nano-fiber research and commercialization occurs. In the meantime we need other ways. Mass production of rockets and spaceplanes seems to be the right thing to do as this has made everything else affordable in the modern world. Mass production of a Shuttle Derived Vehicle for heavy lift is interesting and the external tank could be used in orbit for a spacestation module, a spaceship hull or just for raw aluminum.

CHEAP, BIG DUMB BOOSTER
     The rocket could be made with cheap (compared to titanium) but high quality steel frames that are easy to weld up on assembly lines. The tanks and skin would be of duraluminum that is a bit heavier than lithium-aluminum but much cheaper and easier to weld, bend, etc. It could be fueled up with kerosene that is far easier to handle than LH2 to reduce launch prep costs. The oxidizer would be LOX. I guess it would be a two or three stager with this fuel combination. It might not have a real high payload fraction when you figure in the mass of the steel structure but it could be so cheap to build and launch one of these mass produced monsters that you don't need a real high payload fraction. This low payload mass fraction is one of the reasons the rocket would be bigger than the Saturn V.   The first stage could parachute back to sea for recovery and the second or third stage could be cannibalized in orbit or turned into a pressure hull for a space station. It could be launched from anyplace on the equator from the sea to take advantage of Earth's rotational speed and it would be fueled by a super tanker, although ground launch has more appeal than sea launch. Tracking could all be done by GEO satellites instead of ground based stations, although there would be a central command center somewhere on Earth. The latitude of Cape Canaveral and the Kennedy Space Center is said to be best for launches to the Moon. Either the US has too allow private industry to build nearby or sea launch facilities could be built by companies with experience in off-shore oil platform construction that can be towed to the equator, 25 N or to the arctic regions for launch into polar orbit. Sea launch will be very safe for people on the ground, just in case the huge rockets explode. Another advantage of JP-1 and LOX; it's a lot less explosive than LH2/LOX or hypergolic fuels. I think this concept has a lot of promise.

LUNAR MASS DRIVERS

     We will certainly use mass drivers to launch cargos from the Moon. If we can get 20,000 tons or more of "bootstrapping" payload to the Moon and build a mining and mass driver base, then we could launch ten ton or even 100 ton payloads in rutile heat shielded aerobraking modules every ninety minutes down to a space station in LEO orbiting Earth every ninety minutes. With LOX from the Moon and possibly Al and even Si powders for fuel, we would no longer have to launch heavy loads of fuel up to LEO to propell spacecraft to GEO, the Moon or Mars. Theoretically it will be far cheaper to obtain propellant and space construction materials from the Moon. Mass drivers use no propellant, only cheap electricity, are completely reusable, incur no recovery costs, there are no range costs on the Moon, launch preparation costs are next to nil, and they can be almost 100% automated. In the vacuum without rust or corrosion or damaging severe weather (that can interupt rocket launch schedules on Earth) mass drivers should last for decades. Even if we can only get LOX from the Moon, that's 8/9s of the mass of an LH2/LOX combination. LH2 would come from Earth. If we can combine hydrogen with silicon at the LEO depot to make silane, we can stretch hydrogen supplies even farther.

     The problem is that that Moon is only rich in oxygen, silicon, iron, calcium, aluminum, magnesium, sodium, chromium, manganese, and a few trace elements. There also seems to be sparse ice at the poles. We need a cheap way to send cargos of carbon, hydrogen, nitrogen and elements rare on the Moon into space. If we could just launch 100 ton payloads of plastics, rubber, graphite, copper, computer chips and other cargos with a cheap monster rocket it would save us the trouble of building a chemical factory and a chip factory (a chip factory on Earth costs about $1 billion!) in LEO and/or on the Moon for space industrialization. Once we have mass drivers on the Moon providing most raw materials to lunar orbit, LEO, GEO, Lagrange point stations and anywhere else in Earth-Moon space we will no longer need giant rockets moving things up to LEO, just manned shuttles or space planes.

     There has been some discussion of Earth based mass drivers. Mass drivers on the Moon would need only 1/22 as much energy to put payloads in space as would mass drivers on Earth plus Earth based mass driver payloads could not be nearly as large and payloads would have to be shielded against air friction during ascent into space. Chances are, most of an Earth launched mass driver payload would burn up on its way to LEO. Earth based mass drivers on mountain tops would have to endure severe weather and payload modules breaking the sound barrier would make shock waves that damaged the huge machine. Lunar mass drivers would not need to be nearly as long or as heavily built as Earth based mass drivers. Of course, the only way we could afford mines and mass drivers on the Moon would be to build some cheap rockets to get everything there in the first place. Gerard K. O'Neill and everybody else in the space community thought the space shuttle would be that cheap rocket into space back in the 1970s, unfortunately the space shuttle never flew cheap and even blew up and burned up. This has been a tremendous set-back for humanity.

ASTEROIDS

There are traces of hydrogen, carbon, nitrogen, helium 4 and helium 3 ($3 billion/ton) in the lunar regolith that could be mined if we dig thru thousands of square miles of land. Asteroid mining ships could be built from materials launched from the Moon by mass drivers. These robotic miners would bring back cargos of kerogen, a tarry hydrocarbon substance and precious metals. Asteroids, particulatry C-type asteroids could supply the Moon with enough carbon to produce hundreds of millions of tons of steel, the most versatile of all metals.

A Really Big Rocket

The problem with all our rockets is that they are designed like souped up race cars by efficiency experts who want the smallest rocket with the highest payload fraction and that ends up causing the rockets to be super expensive and unreliable. The most reliable rocket is the Boeing Delta 2 and it blows up 2% of the time! I'm not riding on a rocket like that and what does this 2% failure rate end up costing when you consider that a billion dollar satellite could be lost 2% of the time?

"They" will spend billions of dollars to build the most sophisticated miniaturized satellite or space probe to launch it on a small rocket when for a few million dollars more they could use a larger rocket and build a less sophisticated less miniaturized payload that costs less money! It's absurd! Evenutally, large platforms in space built from lunar materials will replace satellites launched from Earth.

To build the most high performance rocket cryogenic fuels like LH2 and LOX are used. These supercold fuels and oxidizer cause entire tanks to contract. The Space Shuttle ET shrinks by a foot or two in length when fueled up. This requires more complex and costly design and construction of the ET. Fuel and oxidizer pipes must be designed to contract, yet seals and welds can break when super cold liquids flow through them and leaks can result and rocket explode! Valves and pumps can contract and jam up; engines fail and disaster occurs or launch is delayed. When launch is delayed evaporating super cold liquids must be recycled expensively. If launch is delayed too long the launch may have to be scrubbed entirely because too much super cold fuel and oxidizer is boiling off and pressure builds up in tanks and it cannot be recycled quickly enough. Launch windows are missed and this costs money or even entire projects when launch window time is critical for success of the mission.

What we really need is a big dumb booster that uses non-cryogenic kerosene and LOX which is just a "soft cryogen." Also, LOX is not toxic and expensive like N2O4 and it could be made from the air anywhere, including out to sea. So what if the rocket has a low payload fraction? Want more payload? Just build a bigger rocket. Or launch more rockets. As long as the assembly lines are rolling the rockets will be cheap, and first stages can be recovered while upper stages are cannibalized in space. The tanks are not the most expensive part of a rocket and they could be mass produced cheaply. So could rocket engines. This is a job for private industry that knows how to make things cheap and in large numbers! If the price of a space launch drops the demand will increase. So the claim that there just isn't enough demand for satellites and such is baloney. We have enormous tasks to complete in space like SPS construction, relay construction, large telecomm stations, moon mining and helium 3 harvesting, the terraforming of Mars.

400+ FT HIGH 35 FT DIAMETER ZERO STGS. AND FIRST STAGE PARACHUTE DOWN TO SEA. SECOND STAGE EXPENDABLE. THIRD STAGE "CANNIBALIZED" IN SPACE OR USED AS SPACE SHIP OR STATION MODULE. ALL FUELS JP-1 AND LOX. STEEL AND DURALUMINUM CONSTRUCTION. DELIVERS 60 TONS CARGO TO 250 MILE ORBIT AND A 3RD STAGE. NOT CAPABLE OF REACHING THE MOON. LUNAR FLIGHT REQUIRES REFUELING IN ORBIT OR AN ION DRIVEN CARGO MODULE. MOONBOUND ROBOTIC CARGOS PROPELLED BY ION DRIVES AND LANDED WITH HYDRAZINE AND HYDROGEN PEROXIDE. ASSEMBLY LINES CRANK OUT THESE ROCKETS LIKE FORDS AND DESPITE LOWER PAYLOAD FRACTION, COST TO ORBIT OR THE MOON IS COMPARATIVELY LOW.

2ND AND 3RD STAGES MIGHT USE LIQUID METHANE AND LOX INSTEAD. THIS WILL INCREASE PERFORMANCE. LCH4 IS CHEAP AND IS A SOFT CRYOGEN. THE ZERO AND FIRST STGS. WILL STILL USE JP-1 AND LOX SO THAT THEY ARE NOT SUPER COLD WHEN LANDING IN WARM SEAS.

MODULES LAUNCHED TO LEO WILL BE PROPELLED BY ION DRIVES (MPD THRUSTERS) TO LUNAR ORBIT IN ABOUT EIGHT MONTHS. BANKS OF NUMEROUS MPD THRUSTERS WILL BE USED. ONE SET OF MPDs WILL BURN UP IN ABOUT 30 DAYS, THEN ANOTHER SET IN THE CLUSTER WILL BE ACTIVATED FOR 30 DAYS, ETC. POWER WILL COME FROM GALLIUM ARSENIDE (40% EFF.) OR C60 NANOTUBE (80% EFF.) SOLAR PANELS. ABOUT 10% OF THE 60 MODULE WILL BE LITHIUM PROPELLANT. WITH 300 SECOND DESCENT MOTORS, 35 TONS OF PAYLOAD INCLUDING THE SOLAR PANELS THAT WILL BE USED ON THE MOON AND THE PROPULSION SYSTEM THAT WILL BE CANNIBALIZED WILL REACH THE MOON.

AN MPD THRUSTER THE SIZE OF A SHOE BOX CAN MAKE 50 LBS. OF THRUST. MPD THRUSTERS HAVE VERY HIGH THRUSTS AS FAR AS ION DRIVES GO AND VERY HIGH SPECIFIC IMPULSES. THEIR MAJOR DRAWBACK IS THEIR SHORT LIFETIME. THEY WILL BE MASS PRODUCED IN HIGH VOLUME AT LOW PRICES.

TO LEO: $50 TO $100 MILLION. TO LUNAR SURFACE: $1430 TO $2860/ KILOGRAM FOR CARGO.

Perhaps a larger 1st stage is better than four zero stages. Sea recovery ops simplified. What to we call this rocket? The Condor? The Vulcan? The Cobra? The Quasar?

Once we get it launching, energy corporations could afford to build helium 3 mining bases on the Moon. No more space socialism! Or space fascism if you really think about the political-space industry alliance.