AD. Space 2125 (5/14/26, off-topic)

AD1. A climate apology

Some of my solar, energy storage and transit ideas came from my early space and lunar colony designs. For completeness I want this published.

I recognize that space industrialization is going to have remarkably little to do with humanity surviving climate change for the next century, but some day after that, this will matter. For this moment I'm only going to drop a rough outline of where space colonization will be going. Excuse the mess. Enjoy it if you're a science fiction fan.

AD2. Low Earth Orbit resources

Everything launched from earth is vastly expensive, both in terms of cost per kilogram of payload and in terms of fossil fuel expended. We want to gather hydrogen, oxygen, nitrogen, carbon, helium and iron, humanity’s servant metal, in space whenever this is economically possible.

AD3. A high vacuum pump at the very upper edge of the earth's atmosphere

I presented this scheme at AIAA 2006 Dallas and again at AIAA 2008 Long Beach. I also filed a rather dense patent application. I dropped pursuit of the patent application because unfortunately, all of the immediate applications for the patent would have been military in nature. I'm a member of a historic peace church, the Society of Friends (Quaker). I have no interest in military work.

The high vacuum pump will operate in a circular orbit roughly 120 miles (200 km) above the earth at roughly 25,000 kph. All of the quite tenuous incoming gases will be grabbed by a high vacuum pump. The scoop will also be equipped with an ion propulsion engine that can shoot one quarter or more of the gathered gases backwards at 100,000 kph. This maintains the satellite’s forward momentum.

At an altitude of 200 km above the earth, the tenuous atmosphere consists of about 50% oxygen, 50% nitrogen and small but usable quantities of helium and hydrogen. The nitrogen is for the most part usable only for propellant in ion propulsion engines. The money is in the oxygen and the small amounts of helium and hydrogen gas atoms. Oxygen is 16/18 of the mass of water, and if the hydrogen is shipped from earth the oxygen can be combined with hydrogen to create fairly inexpensive water. Next, oxygen is the relatively heavy part of hydrogen/oxygen rocket fuel for fast space transportation needs. Finally, oxygen is what humans breathe to stay alive. Oxygen in space contains isotopes such as O17, and so oxygen will need to be centrifuged before use within humans.

It may be that we'll want solar-powered lasers at a higher orbital altitude to beam energy down to the vacuum pump in a very low orbit. Space is at a premium on the gas gatherer unit because extra equipment causes extra drag. All drag must be compensated by expending extra gathered gas out of the ion propulsion enegine to maintain orbital momentum..

AD4. Mining iron asteroids

Build a primitive solar sail with a control unit. Sail it back to low earth orbit or to earth's L-5 point. Also grab carbon and nitrogen from more carbonaceous asteroids and sail these resources back toward earth.

We need only send one solar sail construction unit to the iron asteroid. One construction method is to blow some kind of bubble surface in a slightly pressurized environment, then vacuum-deposit iron atoms onto a dessicated bubble surface, then use heat to evaporate and recapture the bubble surface material. Then the thin square iron panel is slid out of a slit in the bubble creator and gets attached to the end of a long, narrow sail surface. The sail surfaces are all attached to control wires at the center of an incredibly slowly spinning daisy. Each panel must be carefully moved. This moving technology is a technology that we don't have yet but it's certainly possible.

The ultrathin solar sails of people's dreams will be unattainable. This is a rather heavy, lumbering cement truck of a daisy that will take years to get back to earth orbit. Don't laugh, it runs.

The slowly spinning daisy wheel has a relatively tiny and lightweight central control satellite, a spider device that pulls on its control wires to rotate its daisy petals. The daisy can spin faster or can spin slower almost down to zero. For re-orienting itself toward the sun's rays, the daisy can twist individual petals to face the sun or to not face the sun. This changes the daisy's orientation, the way the entire spinning circle of petals is tacking into the sunshine.

For many decades this will be an economically unaffordable climate change option, but daisies could in theory park themselves at earth's L-5 Lagrange point and block a tiny amount of sunshine from reaching the earth. This would blunt the earth's modern greenhouse effect. The iron daisy would be fully capable of course corrections to maintain its position at or near earth's L5 point. The iron daisy's control unit might need to be upgraded once every 20 years.

More likely, the iron daisies would sail themselves down to a low earth orbit where they would be disassembled and recycled for construction of habitats..

AD5. Mining comets

Use ion propulsion to visit a comet. Bag the comet. On the way back, spend some of the harvested cargo. Take advantage of slingshot effects.

AD6. Getting cargo and then humans off the earth

In theory it's possible, assuming the existence of quite accurate computers, to accelerate a space capsule halfway into earth orbit from the earth's surface, then have an orbiting device that decelerates that space capsule the other half way into orbit. Later this orbiting device will accelerate the same capsule halfway out of orbit, restoring and maintaining its orbital momentum. At first we will experiment with an orbiting electromagnetic "rail gun" that only decelerates capsules of equipment 1000 kilometers per hour into earth orbit, and accelerates the same empty capsules 1200 kilometers per hour back down toward earth. This will move cargo into space while maintaining orbital momentum.

Cargo and someday single human capsules will be launched in Ecuador right on the equator. Ecuador has a 6,000 meter high mountain with the northern edge of its caldera sitting right on the planet's equator. A vacuum tube could be built underground in Ecuador and in the nearby Pacific Ocean capable of launching a human at three gees up into orbit at about 1/2 of orbital speed. Having capsules gain enough total altitude to reach orbit will be an acceleration issue at the launch end. I see upward acceleration, not velocity gain, on the capsules at the volcano end.

I visualize the orbiting decelerator as being a bit of a spider web with many cables. It must re-align itself perfectly after every catch or launch.

Rotational energy is stored by swinging two masses around in a circle at the ends of cables. More masses are counter-rotating nearby. These masses pull on arms that speed up the rotations or slow them down. The arms and various gears pull an electric generator, which generates quite a bit of electric power on demand.

Each capsule has a long "lance" sticking forward for acceleration or sticking backward for deceleration. This 100 meter lance makes for a nice, even three gees of acceleration on the capsule between electromagnets spaced 100 meters apart. For human capsules, it means that we don't have to over-magnetize the human because the heavy duty acceleration is far out to the front of the human capsule..

Hitting the orbiting catcher will be like having a bullet travel up the barrel of a rifle as someone pulls the trigger on the gunpowder. For a cable-based orbiting decelerator, I would expect lots of bounciness and weight distribution on the whole system over a certain period of time. The calculations can be done in theory.

AD7. Modular low earth orbit tourist trap habitats

Build modular units in zero-gee. Periodically remove units from service for inspection and X-raying for cracks in that module's structure. I have certain engineering standards! Swap in substitute modules as needed when a module is out for inspection.

The units will often all be clustered together to conserve the total cost of space-side radiation shielding. The earth side of the complex always has the natural radiation shielding of the entire earth. The radiation shield units in zero gee are modular and not connected to the pressure vessels. Low earth orbit isn't all that safe for real humans, although companies like to pretend that radiation doesn't shorten people's lifespans if it can't be seen.

Low earth orbit will predominantly be about wealthy, then upper middle class, tourists including honeymooners, the cruise ship crowd. The expensive honeymoon cabins and clubs will have expensive genuine glass earth views because that's what makes people happy. Artificial, televised earth views will work elsewhere inside the habitat modules..

You can swing dance with a partner in zero gee. You can slide past your partner and grab on to an extremity, even foot to foot hooking if you're good at that. Wrapping your legs around your partner's torso also works. Swinging around poles, from pole to pole, is nice. A slow motion set of two flying trapezes might work. Televise the live band on enormous video screen walls.

Fairly long distance personal transit within a large zero gee tourist complex can be aided by artificial person launchers and soft catchers on the other end.

Zero gee and earth view will sell, but the long-term club bouncers will need to sleep and exercise in a nearby earth-normal one gee habitat. Anything from 0.8 gees to 1.1 gees might be ok for the workers, although the tourists might be huddled within the .95 gee to 1.05 gee middle of the pseudogravity habitat. A restaurant kitchen at 0.8 gee might be ok, with a bare minimal live human waitstaff in the dining room. Transit from zero gee to one gee can often be by radiation shielded freight elevator, although staff might probably use the additional exercise of pulling themselves up a long ladder to zero gee within a vertical tube.

AD8. The structure of earth-normal pseudogravity in space

As with zero gee pleasure or work, humans will always need radiation shielding aroumd their sleeping habitats in pseudogravity.

For long interplanetary trips, liquid hydrogen molecules are the lightest possible form of radiation shielding.. Keep this shielding very cold.

Every small to medium sized habitati will be a large ball. At the other end of a tether, a relatively tiny counterweight, probably comprised of useful freight such as a landing module, fuel and oxygen, can swing around at ten gees. This puts 90% of the spacecraft's mass within the habitat ball where it belongs. The rotational velocity of the ball and the length of the cable is bounded by humans' ability not to feel dizzy with too much rotation. I've seen a rough recommendation that the habitat must be at least 200 meters from the center of rotation, and any farther away would be slightly more expensive.

The most likely medium scale pseudogravity habitat shape in low earth orbit will be a large ball with counterweight until the ball reaches a size where the top of the ball has 0.8 gees of pseudogravity and the bottom has 1.1 gees of pseudogravity. Above that point the top of the habitat ball starts to flatten out. The habitat ball then starts to look more like a frisbee or a meat pie. The frisbee shape then starts to grow around the rotational circle of the habitat, striving to become more of a torus. At this point individual pseudogravity modules on the semi-torus are on cables and can be hauled up to the zero-gee center of the rotation for periodic structural inspection or replacement.

Eventually the module arrangement expands all the way around the torus and we see something resembling the torus in "2001, A Space Oddysey", albeit the modules can be hauled up to the center on their cables.

Beyond this, the torus starts to grow sideways into a cylinder. At some point in this phase of expansion the radiation shielding jumps to a cylindrical shape, while the modules inside still hold a bit of their torus shape. Eventually we get a classic cylinder pseudogravity habitat.

We're not done expanding. It's possible to have two or more rotating cylindrical habitats tucked inside each other like Russian dolls.

Each cylinder rotates at its own speed. An elevator takes people from the rotational speed of an outer cylinder to the rotational speed of an inner cylinder or to zero gee habitats in the middle. With ten Russian doll cylinders we can get ten times the earth-normal living space out of a single outside radiation shield and a single outside pressure containment vessel. The heavy outer radiation shielding doesn't have to rotate with the Russian doll cylinders, just the cylinders themselves will rotate. Each rotating cylinder only has to hold the mass of its own rotating self together, plus the mass of the humans living on it, any soil, trees and any necessary equipment. It's possible for air handling equipment, stored air reserves and space port docks to be in the zero-gee shielded areas near the multi-cylinder center of rotation.

Each cylinder has multiple floors of room, where the top floor delivers .95 gees of pseudogravity and the bottom floor delivers 1.05 gees of pseudogravity. Given a Russian doll thickness of 10 to 15 meters, each habitat should be able to have perhaps 3 to 5 stories of human apartment building habitat interspersed with 10 to 15 meter tall forest and park areas. I happen to be a fan of vines on trellises because they will grow into place faster than oak trees. Pipe in the sunlight, or use electric lights to simulate sunlight. Rainfall will have to come from sprinklers in the roof. Happy hiking!

We still might see possible zero gee modules in the center of the Russian doll layers of habitat, and part of a big sky cylinder in the center.

AD9. A lunar colony

The moon is close enough to earth that telepresence works with a 2.6 second delay. The delay for telepresence robots on Mars and on almost all asteroids could be as long as half an hour. Given our current robotic technology, all robotic work will benefit greatly from having humans look over unexpected situations as they crop up.

The moon is loaded with certain resources, starting with unprocessed moon dust and moon rocks. Humans are unlikely to get radiation-induced cancer if they are underneath radiation shielding that is perhaps 10 meters thick.

A simple moon radiation shelter can be assembled out of moon dust and sandbags. It's a type of igloo, a mere tunnel with a wide driveway that goes around a 90 degree turn and some room in the back end of the tunnel. It can be assembled by telepresence robots before the humans arrive. To use a lunar shelter, simply drive a wheeled habitat around the 90 degree curve to the main radiation-free inner end of the shelter.

AD10. Dependable lunar power

Place at least four or five solar powered lasers in a fairly high lunar orbit. When sunlight is available and when the lunar base is in sight of that laser satellite, aim that laser at a receiving target on the lunar base. During the 99.8% of the time that the sun is not eclipsed by the earth, at least one solar powered laser will be able to power that lunar base.

Kinetic energy storage in space can be accomplished by setting up two or three wheels where two counterweights are swinging around at the ends of cables. An electric generating wheel, properly called a dynamo, is at the center where these geared wheels are linked together. The third wheel would be because the first two wheels aren't swinging in exactly the same circle, so the third wheel makes up the momentum difference at the dynamo. Putting these dynamos on the energy-shipping satellites will cover a power loss during an earth eclipse of the sun.

A heliostat mirror can reflect some of this incoming power down a radiation shelter's driveway, around the curve with additional mirrors, and onto a habitat.

As a backup power system, my gravity-based power storage scheme, shown at G. Electric power storage with an automated ski lift , was originally designed for storing massive amounts of power for the 14 day long lunar night.

I suspect that a microatmosphere of positively charged moon dust particles at the moon's surface should be inhibited by spraying electrons through this microatmosphere. Moon dust particles can get into the works of robots and grind down important joints in the robots.

Probably the first lunar building material will consist of lunar dust placed in molds and solar-heated with concentrated solar energy into a type of rock. Beams for construction, roadbed tiles and half-spheres or half-cylinders might be fabricated. If half-spheres are lined on the inside with plastic and if weight is applied on top, low pressure gases or water could probably be stored within these spheres.

If this operation is performed under glass, the lunar dust should outgas oxygen and the oxygen can be captured.

The first purpose of humans on the moon, other than scientific inquiry and tourism, will be for immediate telepresence for robots on the moon or in lunar orbit.

I picture a lunar habitat where part of the habitat is an oxygen-free (to prevent flash fires with iron filings) metalworking shop for the construction of robots. Chips and micro-motors will be shipped in from earth. Larger parts will be fabricated out of moon materials. Humans can work in this environment with air tubes and with emergency oxygen bottles in case the oxygen tubes are accidentaly punctured. Through an airlock is the 100% oxygen human habitat.

We will see iron mining equipment that scoops up lunar dirt, then drops it smoothly down next to an electromagnet. The iron particles are pulled to the side from the falling stream of dirt, so that a 90% iron payload is gathered. This iron will later go past a second electromagnet and then will be solar heated. Rocks and slag hauled away by the ton will make good clean fill for the sandbags. Iron should be a premium product.

A form of glass might be created from silicates. Glass fiber sandbags are a possibility, but iron mesh sandbags are probably easier to create in such an iron-rich environment. .

AD11. Lunar colony expansion

In time I would expect to see multiple lunar habitats. All habitats will need safe rooms in case that habitat has a catastrophic air leak.

I can imagine a transportation system, a bus or rail system, that takes humans and freight from one habitat to another habitat. These shuttles will dock at airlocks built into each habitat. In time the radiation shielding above the shuttle's roadbed will be thickened to cut total radiation exposure to the humans.

AD12. Balancing on one rail

Putting wheels into the lunar dust has its problems. Dust particles can get into gears and airlocks. It might make sense to lay down one rail for transit. One rail on the ground and not two rails is possible with a modern transit pod system. Balancing on one rail would save money and materials.

Also, my Teleport Transit system would solve the problem of touching and disturbing moon dust.

AD13. Finding carbon on the moon

In Argentina, a series of gouges in the land show where an asteroid hit the earth at an oblique angle. The asteroid's two pieces bounced about 14 gouges into the plain's soil and rock. Carbonaceous asteroids have certainly hit the moon at a similarly obliqe angle. I now challenge astronomers to find telltale tracks where an asteroid has bounced across the moon and the remnants have probably come to rest buried underneath the collapsed wall of a crater. That large asteroid can be mined for carbon, for nitrogen and for hydrogen.

AD14. Finding oxygen in an under-dust lunar atmosphere

Let me throw out a conjecture. The ground beneath the lunar dust is fractured. It's full of cracks. The surface has been blasted with microparticles and is somewhat sealed.

It's possible to create a surface of lunar dust, no rocks, over a relatively wide area. It's possible to put intense solar heat on small section after small section of this surface, fusing and sealing the surface. It's then possible to solar heat the center of this section with lasers from orbit. This should create underground oxygen on the bottom of the heated target as the local area is weakly sealed from the top down.

Drill a well for gathering such high vacuum air as exists from the heating process. The moon dust surface can, if you groomed it, be impervious to releasing air, allowing buildup in the many cracks beneath the surface. Why mine oxygen when it will come right to your habitat?

A ring of dust-covered pipe or a trench filled with small moon rocks for air drainage around the heating spot will help channel most of the oxygen to your piping system.

AD15. Multiple layer air leak collectors

When the habitat is separate from the radiation shield, the radiation shield can act as part of a second microatmosphere air lock. When minor amounts of some air leaks out, recapture most of the air that escapes the inner habitat with a high vacuum pump. On the moon, lunar dust can easily get stuck in the seals around airlocks.

AD16. Multiple bowling balls as a heat transfer medium

Lunar dust can be solar-cooked into ofjects of almost any shape. Given a large supply of rather massive bowling balls they can be heated or cooled, then rolled into airlocks that have almost no air between the spherical ball and the airlock's spherical sides, then rolled outside for dumping heat or for gathering heat. In an airless environment, mere bowling ball return lanes are a simplified way of transferring excess heat from a habitat, through a thick radiation shield to the outside and transferring coldness back in as needed. With any reasonable amount of computer control, it's possible to use only one bowling ball return lane for transferring bowling balls in two directions. Bowling ball storage racks on both ends will be needed.

AD17. The lunar elevator revisited

An elevator from the lunar surface to L-5 has been shown to be either wildly expensive or impossible to build.

The delta-vee to reach low lunar orbit from the lunar surface is quite roughly 3600 miles per hour, 6000 kph. I leave the calculation of the perfect low orbital velocity to the world's many non-inventors. It's easier to reach low lunar orbit than high lunar orbit.

The idea of accelerating an object to 50% of orbital velocity, then using an orbiting decelerator to decelerate the object into full orbital velocity, can work on the moon. The moon has approximately zero atmosphere, so that low lunar orbit can be as low as one kilometer above the lunar surface. It remains to find a scheme to accelerate an object to 1800 mph, 3000 kph, on the lunar surface.

As previously suggested for earth launches, a rail gun on the surface and a reverse rail gun in orbit will work. However, at the relatively low velocity of 3000 kph, a capsule swinging at the end of a cable is also a possibility.

The exact spot of the south pole is on the edge of a large crater. I'm going to assume that a major lunar base is set up on that edge of the south pole crater. One alternative to a rail gun is swinging the capsule at the end of a cable.

The cable will have to be held up against the 1/6 lunar gravity. To handle this gravity, a type of suspension bridge will need to be built. A heavy counterweight can be on the back end of the swinging bridge, and the far end of the bridge can simply be held above the lunar surface by centripetal force.

The orbiting swinging cable will be in a near-polar orbit. It will pass a few kilometers out from the lunar south pole, always the same distance from the pole, every 90 minutes. Both swinging cables will need to decelerate, to put a swinging capsule onto the lunar surface or to put a swinging capsule in full low lunar orbit, and then to put a capsule into full swing.

At a specific second the swinging tips of the cables will approach each other perfectly, with humans in such capsules experiencing three gees.. The tips of these swinging cables will have perhaps one second to transfer their respective capsules to the other cable tip, and to receive the other tip's capsule, or possibly to abort the transfer. In this way a scientist, worker or tourist can move from low lunar orbit to the moon's surface, and another tourist can come from the lunar surface to low lunar orbit. Once in low lunar orbit, a capsule can be accelerated quickly with rocket fuel or freight can be accelerated slowly with an ion propusion engine.

If iron or other raw materials are raised from the moon, some total orbital momentum is lost. This orbital momentum can be restored with the use of an ion propulsion engine. Also, if one swinging cable achieves 3100 kph and the other swinging cable tip has a rotational velocity of 2900 kph, perhaps a net momentum shift can be worked out for the orbiting cable that compensates for additional amount of mass being uploaded onto the orbiting cable system.

AD18. Earth-normal gravity on the lunar surface

The easiest way to manufacture gravity on the moon is to build a circular railroad track. Run a rail car around and around. Build a sandbag radiation shield over the entire track. Stop the rail car every hour or so to transfer people from a transfer pod onto or off of the rail car.

When a second rail car is built, add it onto the end of the first rail car. Keep adding cars. Take cars onto a siding for regular inspection and maintenance.

Eventually the train might extend all the way around the circle.

Next, build higher and thicker circular trains. At some point build connecting beams on the train so that the circular train holds itself together against centripetal force.

Add an elevator with two stops. When the elevator is motionless against the lunar surface, a groundtransportation pod locks on and a hatch opens, so that people can get to and from other habitats and workshops in the colony. When the elevator is rotating at the same speed as the wheel, a hatch opens so that people and freight can get onto the moving wheel.

Next, have multiple concentric wheels underneath the same radiation shield.

AD19. Painting a target in very low lunar orbit with rare earth metals

As an orbiting target passes low over the moon's surface, use vacuum deposition to add rare earth metals and platinum to the target's surface. At some point redirect the heavy target to a higher lunar orbit with ion propulsion, then drop it as gently as possible into the earth's outer atmosphere with heat shields and parachutes. Sell the rare earth metals.

AD20. Lunar manufacturing

The best place to grow food for a low earth orbit tourist trap might be under lunar radiation shielding. Oil-based sealants would probably be derived from moon-grown plants. With humans on the moon to control telepresence when instant telepresence is needed and with some variety of raw materials, the moon could be a manufacturing hub.

It's possible to build a colony-sized pressure vessel out of one thousand interlocking pieces that link together to form a sphere, so large structures might be custom-manufactured on the moon, then raised into lunar orbit, then transported by ion propulsion engine to various orbital sites.

AD21. Interstellar transit and migration, seeding the Centauri system with a micro-robot

The optimum way to accelerate a satellite to any velocity remotely approaching light speed is with photons blasted from a laser into some type of sail. We will need a terribly long line of such lasers to reach, say, half of the speed of light or even one tenth of the speed of light.

The only way to decelerate a microscopic satellite into the orbit of another star system is to accelerate a long line of lasers toward that star system. Activate this long line of lasers as it approaches the other star system.

AD22. Seeding the Centauri system with human beings

Build a big line of decelerators in the other star system. Build the colony using that self-replicating micro-robot.

Send the ship in pieces through the accelerators. Have a whopping big radiation shield of liquid hydrogen.

Send tiny girls who become tiny women. Send two women because it will be incredibly lonely otherwise. Send lots and lots of frozen fertilized embryos. I'm a pessimist here, so I assume that one of the two women dies enroute. Half or three quarters of the embryos will fail to come to term. It would take over one century to populate the colony with one million people. Bring out the male embryos last.