we might be only a couple of years from discovering a way to increase the energy density of plasma, or ion drives. It’ll probably involve nanotubes, they seem to come up with a new use for them every day. They also seem to have an abundance of interesting electrical properties. Maybe they can use them to make tiny rail-guns that could accelerate one ion at a time to relativistic speeds. Put several trillion of them on a 1 square inch chip and maybe they can get a couple pounds of thrust. The F-1 engines on the Saturn 5 put out about 90 pounds of thrust per square inch of exhaust area, so we will need to cover a lot of area with ion thruster chips (slightly more if they’re barbecue flavored).

Amusingly, the next generation of spacecraft may very much resemble “flying saucers” since their shape will be a compromise between thrust surface area and being aerodynamic enough to travel straight up and out of the atmosphere at a decent speed….say 300 – 400 mph. Remember how the bottom of those things always glowed?

At least we won’t need heat shields, we’ll just use our ample supply of power and propellant to slow down from orbital speed and float back in at a couple hundred MPH instead of 14,000. Much better than hoping to God that you haven’t developed a pinhole in your shield! For now, we’ll probably have to use one or two submarine fission reactors for power, so this thing is going to be big. But hey, the fusion guys say they might have something ready in about 50 years!

Actually, I really do think something like this will happen.

Three Space Scuttle liquid engines sum to 1.125 million lbs of thrust. Saturn’s five F-1A engines summed to 9 million lbs of liftoff thrust ( but had no recycle value). Space Scuttle solid fuel boosters do 2.6 million lbs of thrust each. Being 12 feet in diameter, eight of them fit around a 33-foot diameter Saturn V with elbow room. The Space Scuttle is safety downrated below 25 tons cargo. The jury rig would boost ~700 tons (28 Space Scuttle launches without 28×120 tons of parasitic Space Scuttle).

The NR-1 nuclear submarine weighs 400 tonnes fully loaded plus crew of 12. Trade heavy propulsion plant and underwater whatnots for water and MREs. Oxygen from electrolysis of water. All compartments have pressure bulkheads and hatches. Pressure-sealed toilets, too. Add external airlocks with dust scrubbers. One launch for Moon base and consummables plus lunar insertion engines, one launch for landing package and surface operations; one launch for personnel, emergency return vehicle, odds and ends.

Build the submarine in aluminum to conservatively lose 130 tons or carbon composite to lose 160 tons. Bury beneath 10 meters of lunar regolith for temperature and radiation buffering.