Space-based Civilization

Hello DrMoose

The finest place from what we are used to, would be at one of the Earth's Lagrange points preferably in a hollowed out Asteroid, or one at each Lagrange Point.

As I see things, Earth's Moon should have been colonised at least some 20 years ago, in hollowed out areas at least 100 metres under the surface, away from minor meteor impact, and the Moon inhabitants could have been supplied with exercising gymnasiums to ensure no muscle wastage and consequent bone density loss, plus ultraviolet lamps to run the self-sufficient food systems, and ensure proper Vitamin D formation.

As far as actual Terraforming of an entire planet, Mars is the best hope at present, and likewise many structures would need to be built well underground, because the two Mars satellites, Phobos and Deimos,. are not large enough to stop most of meteoric impact on the Martian surface, unlike the rather unique situation we have here with the Earth and its Moon.

Sure, for a start supplies would be needed from Earth, but over time the Settlers in other places could become self-sufficient.

That's my first thoughts on the subject, and I could easily write a or more, but best to give other readers a shot.

Kind Regards....

Space is a dangerous place. If the cosmic radiation doesn't do you in, the micrometeorites will likely take their toll on you. A paint flake traveling at 16,000 miles per hour, etc. is a massive threat.

Certainly, I'd like to visit, but I don't think I'd want to live there. Starting a colony in a such a remote location is difficult in any age. It would take incredible investment and it would be very risky. I'm sure it would be difficult to find investors without some fantastic return on investment like a mining operation for heavy hydrogen.

If we ever master continuous fusion energy based on heavy hydrogen, it might be worthwhile. But then, we always have a lot of heavy water around anyway.

But the idea of a wagon wheel shaped space station is really cool. Especially with the water reserves (and swimming pool) located in the hub. NASA has considered various designs for some time. All we need is money and a lot of heavy lift vehicles.

DrMoose wrote: "Pollution becomes a non-issue"

At the risk of bursting part of your bubble, pollution is already an issue. In fact, it could cancel the final rescue mission to the Hubble.

Directors must vote Yay or Nay on the flight soon, after they have evaluated the risk factors associated with flying the shuttle though the debris fields near the orbiting telescope. The launch is schedule to be held in just a few weeks.

The recent deliberate destruction of orbiting satellites with missiles, first by China, then again by Russia, have littered the orbit with a sufficient number of large chunks of metal to perhaps pause a serious threat to the mission. Most of the junk up there is ours so it isn't just the other guy who is making the mess.

When the statistical odds of striking a piece of space junk reach a certain threshold, project directors are required by law, to sift through current information and make a final Go or No Go decision.

Given the rate at which space launches are being conducted, the situation is destined to get worse before it gets better.

Given the cost associated with cleaning up the space around the earth, I can't imagine anyone proposing a clean up crew anytime soon.

Obviously, someone has to take responsibility for changing attitudes about littering in space.

As for the rest of the proposal, there are lots of things that are said to be possible in a zero-gravity environment. One of the most notable was micro chip production which requires a high vacuum here on earth to work.

If an economical way can be found to lift spent uranium fuel rods into orbit, it would not take much more energy to send them "downhill" into the solar furnace. There are a lot of people in Nevada who'd rather see that than the current plan to bury them underground for a few hundred years.

It's long been held that a solar collector could accumulate enough energy from the sun to beam it down to earth to microwave collectors that could then redistribute the energy to where it's needed., No more dependency on fossil fuels.

L. J.

A few more thoughts.

Yes, space is a dangerous place. It is without a doubt the most hostile environment imaginable. Not only is there a lot of junk flying about at very high velocities and disturbingly high levels of radiation, not only does prolonged free-fall do bad things to a human body, in terms of it's ability to return to a high acceleration field, but there is the simple fact that there aint no air up there! And explosive decompression can just ruin your whole day.

However, these things are mere engineering issues. For example, once you've processed an asteroid for it's useful materials, what remains can quite easily be used as shielding for your habitat. A few meters of this stuff will stop quite a bit of radiation, and soak up all but the worst meteor impacts.

I said previously and I maintain that pollution is a non-issue, for a space-based civilization. If you place all of your waste into the focus of a rather large mirror and aim said mirror at the sun, the waste very quickly falls apart into it's component atoms, which can then be seperated and re-used. Furthermore, given unlimited solar energy, I should think that a good engineer could design a magnetic broom similar to the ram-scoop field of Bussard ram-jet with which one could quite quickly and efficiently sweep up all of the trash which litters low Earth orbit (LEO).

Quite correctly, space is the best place to collect the unlimited solar energy. We have the technology to build large platforms (made from rolled foil) on which we can mount solar panels. The only technical glitch is how to get that energy back to the ground (earth) because no one has yet designed or built a microwave tube that can handle the megawatts one would want to transmit.

But if we had the microwave tube, we could send a fairly narrow beam to be collected by a passive array that allowed 50% to 80% of the daylight to pass through it. Which means that the land required could have a couple of uses.

A microwave beam that powerful could make an awesome weapon as well as a substantial liability. The space based utility would assume a huge liability to keep the beam from drifting off from its target array. And, its not like we could have a hard wired e-stop button down here on the ground in case it did. So for now, its a little like living under high voltage transmission wires suspended by towers that were built by the lowest bidder. Only worse!

As for the magnetic broom, not all of the space junk is going to be affected by a large (and relatively weak) magnetic field. Even if it was affected, how do you keep from sweeping up legitimate satellites? So, if you can't do that, then the next best thing you can do is design space ships that are surrounded in a series of toroids that have a superconductor inside them with a high circulating current that, in turn, provides a magnetic deflector shield. Or, perhaps one could build a large scale electrostatic filter similar to the electrostatic filters used on HVAC systems. Still, you would have to watch out for satellites (wouldn't want to knock out the sports channel satellite relay station).

It seems to me that we have to first establish a mining operation on the moon. This would give us a good starting point for other activities. There is plenty of material there which can provide shielding and basic building components for glass and titanium, but no plastics. And the LaGrange points don't have a lot of trash as yet, but lifting the materials to build something there with all of your resources from earth is more expensive than a moon base. First things first!

Joe makes a very good point. The biggest single obstacle is the expense of getting started. Dr. Gerard K. O'Neil examined the idea quite a few years ago and published a book entitled "The High Frontier", which goes into what seems to me to be a very good step-by-step plan for bringing it to fruition.

Dr. O'Neil's concept starts with establishing a modest habitat and engineering station in HEO and a mining station on the moon. The moon base would use an rail gun to loft lunar regolith, which contains usable quantities of oxygen, silicon, iron, aluminum, titanium, and so forth, to the orbiting station, which could then use solar energy to process this stuff for materials which could then be used to construct habitats, power stations, and so forth. As capacity increases, spacecraft could be built to travel to the asteroid belt to find and return to Earth asteroids containing light elements which would otherwise have to be lifted up from the surface,thus lowering the cost of the enterprise and bringing it closer to self-sufficiency.

A further thought, regarding getting power from an orbiting solar power satellite to the ground.

The nicest way to get from Earth surface to orbit would be via a space elevator, or skyhook, comprised of a very long tether anchored to the surface on the one end and to a suitable counterweight at the other, with it's center of mass at geo-sync orbit, slightly less than 36,000km, and with electromagnet, linear motors attached to it to run capsules up and down it's length. The likely material for such a thing is carbon nanotubes, since nothing else we know of is anything like strong enough to handle the tension it would have to endure. Now one variety or nanotube, the single-walled, is an excellent conductor. So, it would be a simple matter to engineer the tether to carry solar power down to the surface, thus avoiding all of the issues of beam transmission.

I do admit that I wonder about loss over such a long power-line, as I have no data on dissipation in nanotube conductors, though what I have read suggests that they are likely better even than pure silver.

Hello DrMoose

There are some major problems to solve, if such an idea ever came to pass:

Lightning problem for cable, travellers in the movable elevator, and the huge "Earth Mat" required at the ground level.

"Insurance policy" in the form of an auxiliary tether, in case the main cable ever parted, otherwise nearby folks may be whipped from the damaged sky tether.

If the cable ever parted, recovery of equipment and persons at the "top end".

Kind Regards....

Sparky,

Oh, absolutely, there are problems to be solved with a skyhook. But at this point they are well on their way to becoming engineering issues, and we can always solve those. As of right now, it looks like we can build one, and sooner rather than later. So the question is, will we?

Moose

Hello again DrMoose

My thoughts re the Lightning problem is to turn that erstwhile problem into a useful product.

Once Supercapacitors of sufficient size in Farads are made, and are cheap enough, to interpose an arrangement of those Supercapacitors between the lower part of the "lightning rod" part of the "Skyhook" and the Earth Mat.

By this means, a lightning strike would charge the Supercapacitor network.

The Supercapacitor Network would store the lightning pulse, typically 20,000 Amperes at 15,000,000 Volts through 40,000,000 Volts.

The stored energy could be released over time, via a " split the Supercapacitor Bank" arrangement of switching, and the Supercapacitors thus discharged in turn via a DC/AC Inverter step-down Voltage method, into a storage battery network, then into the local Power Network through an import/export metering arrangement.

The thing is, that the lightning pulses are free, although sporadic, and the obtained energy should pay for the storage/inverter equipment, plus the running costs, particularly if the "Skyhook" was located in a "Lightning-prone" area such as Florida.

Kind Regards....

Sparky,

I like the idea of harnessing the lightning. It's one more way of capturing the solar energy that falls upon this planet a putting it to work, and the amount of electricity there is staggering. Based upon your numbers, three-eight hundred gigawatts from a single lightning strike.

It occurs to me that some sort of system would be required anyway, to prevent such a massive surge from burning out a skyhook's entire electrical system and that of any attached space stations or powersats.

As far as locating a skyhook, it seems to me that we would want the orbiting works in a geostationary orbit, which is to say in a single, fixed point over the planet, rather than in a geosynchronous orbit, in which they would track a figure "8" over the surface, thus increasing the forces acting on the tether. Which of course means that any space elevator would just about have to be built on the equator. Which I might also add would be a huge financial deal for the nations with the elevator in it's land.

Moose

Hello

<"....three-eight hundred gigawatts....">

Remember that the figure is over a very short time interval, usually less than ¹/₁₀ second.

We generally rate electrical supply in terms of the Watt-Hour, or kilo-Watt-Hour (kWH), which does reduce that large figure.

Even so, should the method of capturing the energy of a lightning strike be possible, then a new resource of energy in the form of electric power could prove useful.

There is another method of obtaining "free power", from the approximately 3kV per Metre of vertical height above the ground.

For that large suspended arrays could be built in the troposphere, which could capture this charge and conduct it below, for storage.

That charge is constantly replenished, although like lightning, it is DC, of course.

Kind Regards....