Space Luxury Liners
                                                                             by Dave Dietzler

     In the early decades of lunar industrialization astronauts will fly to the Moon in small ships similar to Peter Kokh's Jules  Verne powered by hydrogen and oxygen.  The hydrogen and oxygen will be 'up-ported' from Earth initially in the form of water and it will be stored in LEO depots where it is converted to hydrogen and oxygen when needed to fuel up a rocket.  Hydrazine and nitrogen tetroxide will also be shipped up because these won't boil off during a three day flight to LLO and will be used for retro-rocketing into lunar orbit.

     On the Moon, hydrogen will be scavenged by robotic volatile miners harvesting helium 3 or just harvesting volatiles for their own sake and similar machines will mine water from the polar ice fields.  Water will be stored at a depot in LLO. When ready to return to LEO the hydrogen and oxygen will be made from water and the ship will be loaded up.  It won't need hydrazine and N2O4 for return because the spacecraft will aerobrake into LEO, rendezvous with a space shuttle of some kind and the astronauts will return to Earth.

     Small Moon Shuttles that ferry passengers from the lunar surface to lunar orbit and back could use LH2 and LOX for brief flights to LLO and back in a few hours before the cryogenic fuels began to boil or they could use nuclear thermal engines and plain water for reaction mass. Getting those NTRs (nuclear thermal rockets) might cause some outcry on the Earth, so I don't know if they will ever be used.  It would be a help if nuclear rockets have some use albeit a limited one.  We will need nuclear powerplants for lunar crews to survive the lunar night until massive fuel cell banks are constructed. 
    



























    
    When industry has grown on the Moon and money is being made from helium3,  solar power satellites and platinum mining in iron asteroid impact craters, the time for tourism will come.  Cycling stations could be made from external tanks mounted on ends of a long boom that rotates to produce centrifugal force or "artificial gravity."  These cycling stations will carry a few hundred people in decent comfort. 

    Taxis to and from the cyclers will burn a monopropellant made from silicon, aluminum and LUNOX.  This will be launched to lunar orbit by mass drivers in insulated payload modules with high pressure cold gas thrusters on them that allow a low velocity maneuver for rendezvous with freighters in lunar orbit.  The NEP freighters will haul the monopropellant to L2 and L1.  From L1 a small chemical rocket burn will send the monopropellant down to LEO in aerobraking containers.  It might be possible for solar electric freighters to make a long slow spiral down to LEO also.  Boil off reliquefication will be required.  It might also be possible for huge mass drivers on the Moon to launch 100 ton aerobraking modules of propellant directly to LEO every ninety minutes when the LEO depot was coming around.  We might even launch loads of silica, magnesia and alumina extracted from moondust that don't require any boil-off reliquefication and process out the monopropellant in LEO and at L2.

     When mining and industry gets really big on the Moon we will need space luxury liners.  These will consist of four "hatbox" shaped counter-rotating centrifuges each 100 meters in diameter.  There will also be a weightless section protruding from the hub and a garage for the taxis.  The garage will not be pressurized because that would necessitate huge air-tight doors for the taxis to enter.  Instead, the oval shaped garage will have big gull wing doors and the taxis will maneuver into it with thrusters and dock with airlocks inside. The garage will have a polyethylene radiation shield so that workers inspecting, maintaining and repairing systems on the outside of the taxis will not be harmed if there is a solar flare before they can get inside the giant luxury liner.   They will be shielded from solar heat and work by artificial light or just enough light piped in from heliostats.  This way they will only have vacuum to deal with and not hard radiation and extreme heat or cold in space.

     Aboard the cycling station tourists will enjoy spacious cabins with all the normal conveniences-coffee makers, king sized beds, showers, flush toilets, etc.  Artificial gravity will greatly enhance the comfort of space travel.  They will be able to sit down and write or eat and even cook normally in kitchens for the passengers at one-sixth G during the seven day trip for Moon bound travelers.  Those headed for Mars will have about 0.5 to 0.6 Gee so that they can transition from 1 G to 0.38 martian G easier and transition from 0.38 martian G back to Earth normal 1 G on the six month voyage home.

     The luxury liners of space will have a full sick bay that is actually a small hospital where the most sophisticated medical procedures and lab tests can be carried out; even heart surgery.  Nobody will risk death due to isolation from medical care. There will be dining halls and bruncheries where meals prepared by the crew are served.  There will also be kitchens for the passengers to cook homestyle meals in for enjoyment and something to do.  Libraries filled with books and movies on DVD will be had.  Every cabin will have a lap-top computer, DVD, 52 inch flat screen TV and CD player. The walls will be sound proofed for privacy. Gyms, hot tubs, saunas, a small swimming pool, juice bars, coffee shops, and even bars where alcoholic beverages are served will exist.  There will be smoking lounges with heavy duty air filtration, billiard rooms, table tennis, card rooms and a small casino with black jack and other games as well as some slot machines.  There will be dance halls and chapels.  There could even be meeting rooms and counselors aboard for AA meetings, group therapy, general support groups and such.  There will be numerous cinemas.  Just under seven days to Earth will be easy.  Six months to Mars won't be hard either for people who have a passion for the Red Planet.  There will be gardens and hydroponic farms.  The large cycling stations will be self-sufficient when it comes to most foods.  Frozen meat and fish will have to be supplied by freighters.

     The one hundred meter centrifuges will be about 25 meters thick.  There will thus be 7850 square meters on the outer deck.  That's 84,450 square feet.  The three outermost decks then will have about 240,000 square feet which is enough to provide 380 square feet of cabin space per person if we don't count hallways.  With corridors I estimate 350 square feet per person or a cabin for two that is 26 feet square.  If each deck is three meters thick with an eight foot ceiling and about a foot and a half for ducts, wiring and plumbing, there will be 12 decks if we leave a 28 meter wide tubular section in the hub where LSS devices, numerous elevators, and other machinery is located.  There will also be storage in the hub as cargo doesn't need gravity.  With three decks for cabins that leaves nine decks for all the other facilities.  The "gravity" will be lower as one approaches the hub.

     Protruding from the hub will be a large spherical chamber for weightless fun that also has some small private cabins.  Observation chambers will be located in this sphere. Passengers will take spiral stairways or elevators up to the hub.  They will enter elevator cars that spin around the hub until matching its slow speed.  The elevator cars will then enter the stationary hub and ride along the spin axis to the spherical "zero-G" fun chamber.  They will also be able to stop, then match the spin of another centrifuge thereby allowing visits to fellow travelers in other centrifuges.  These elevators will also be used to reach the weightless taxi garage to board or leave the taxis.  The total mass of the aluminum ship will be about 12,000 tons; roughly equal to that of a naval destroyer.  It will be much larger because it will be made of thin aluminum instead of thick steel.  There will enough polyethylene radiation shielding to protect the passengers to a level of about 20 REM from a solar flare no matter where they are on the ship.  There will also be more heavily shielded solar flare shelters so that space radiation does not harm them at all.

     Once the 12,000 ton ship built from metals launched from the Moon by mass drivers and assembled in space is propelled onto its orbit by VASIMR drives it will ride for free making use of its mag-sails and solar sails to adjust its orbit and compensate for gravitational perturbations.  Since a single O'Neill colony would amass about 100 million tons, we could build 8333 space luxury liners for the price of launching mass for one big space colony!  Perhaps O'Neill colonies will be built not only for workforces to build solar power satellites but also to build space luxury liners.  Once the SPSs are built and selling clean electricity to the Earth, the space colonists and Moon miners could go bust because those SPSs will last for decades, even centuries in the rust and corrosion free vacuum of space.  There will be no use for the space colonists anymore unless they find a new business and tourism to the Moon and Mars would be grand business for them to go into.
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