Saturday, March 26, 2011

Worlds For Man - Part 0 - Introduction and The Sun

"Worlds For Man - Sol"

(c) 2007, 2011 by Jordan S. Bassior


This is an overview of the colonization and economic potential of the Solar System. In general when I talk about "Near Term" possibilities I am referring to throroughly known engineering; "Middle Term" assumes the possibility of considerable engineering progress and some scientific progress; and "Long Term" of vast engineering progress and major scientific progress. Obviously, the longer the term, the greater the speculation involved.

I considered doing it in terms of the rough time frames, but realized that I have no good way to predict the speed of scientific and technological progress. If you believe the most fervent advocates of The Singularity, we might get to "Long Term" levels of progress by 2050 or so; otherwise, I would imagine it would take many centuries.

I'm doing the system from the inside out.

The Sun

We normally don't think of the Sun when we think of space colonization, but it does contain some 99% of all the mass in the Solar System. Of course, it's hardly an inviting environment: at its surface the temperature is 5500 K, high enough to vaporize any substance we know how to make. This temperature climbs to 13.6 million degrees Kelvin in the core, enough to fuse hydrogen, which is exactly what happens, and what produces most of the Sun's energy (the rest being produced by gravitational pressure).

The Near Term exploitation of the Sun, therefore, centers not around colonization but around energy extraction. The vast majority of the Sun's energy, of course, is wasted from our point of view, because it is merely emitted into space without striking the Earth or any other worlds in our system. So the first thing we might do would be to intercept that energy and convert it into a usable form.

A solar panel in orbit at 1 AU (the Earth's orbital distance) from the Sun will receive 1.366 kilowatts per square meter of energy. If it were at orbit at 0.5 AU it would thus receive 1.866 kilowatts per square meter; at 0.25 AU almost 3.5 kilowatts per square meter, and so on (following the Inverse Square law for radiation).

Therefore, it follows that if we had a mature interplanetary transport capability, it would make sense to station our solar energy panels as close to the Sun as possible. There are, of course, tradeoffs: the closer the panel is placed to the Sun,  the greater the drift imparted by radiation pressure and the more heat it must dissipate.  These are both serious issues, as the former complicates the task of beaming power to the receiving-stations, and the latter risks loss of one's collectors.

Getting the energy back to the Earth or other inhabited places is in principle easy: one would connect the solar panels to a maser emitter, and beam the energy as microwaves to a receiver near where the energy was to be employed. The details of such systems have been long explored in both science and science fiction:  basically, one uses the reflection from the transmission to keep the beam on track and safely shut the beam off should it wander off-target.

Such an endeavor, once begun, would be highly-profitable, making it a practical project for any civilization which has reached the point of routinely sending at least robotic devices to the vicinity of Mercury, the planet most logical as a source of mass for the project.  Obviously, placing a crewed station on Mercury itself would be the easiest way to manage the mining operations.  More on this in the next installment.

In the Middle Term, our engineering and our materials science might advance, enabling the solar panels to be placed closer and closer to the Sun. If we developed a really good energy absorption and retransmission system, this might work as a cooling device for a spacecraft, enabling manned exploration of the corona and unmanned exploration of the deep photosphere.

One exciting idea would be the remote manipulation of Solar substance by means of powerful electromagnetic fields. Such fields might be externally generated, or might be used as catalysts to reshape the exceedingly powerful electromagnetic fields which the Sun generates naturally. This might enable the direct mining of the Sun for matter (mostly hydrogen and helium, but truly vast quantities of both, and even the heavy elements become significant when you filter enough Solar matter). Another application might be the generation of extremely powerful energy beams ("Doc" Smith's "sunbeams"), for military or engineering purposes.

In the Long Term, we might develop materials science (possibly employing generated force fields, or exotic matters) to the point where we could maintain organized structures at the immense pressures and temperatures inside the Sun. This would enable actual colonization of the Sun itself, though probably not by organic life forms: such writers as Arthur C. Clarke, Stephen Baxter, and John C. Wright have imagined these sorts of operations.  Among the purposes might be colonization (by greatly-modified or uploaded humans in the form of exotic-mater machines) or the formation and extraction of exotic forms of matter creatable only under the extreme conditions prevailing within a star.  Another aim might be the direct  management of the Solar power cycle, to a variety of possible ends.

Next: Mercury


  1. Colonize the sun? COLONIZE THE SUN? Oh, this is too much.

  2. Sorry, Yama -- do you actually have a point? I made it very clear that I was talking about highly-modified human descendants or exotic-matter machines doing this in the very far future, not Mark One standard humans doing this any time soon. I'm quite aware of, and in fact explicitly-referred to earlier in the article, the reasons why solid matter as we today understand and control it couldn't retain its organization inside a G-class star.

  3. For Lilac and Datura's, and everyones, benefit: let me explicitly state the structure of my analysis.

    "Near Term" refers to things that we could do now, if we had the infrastructure in place -- they would require no fundamental scientific advances, merely the creation and deployment of technology. In this specific instance, this includes projects such as deploying solar power collection and transmission satellites within the orbit of Mercury.

    Middle Term projects would require some advances in science, in addition to advances in technology, to be possible. For instance, in this case, stationing solar power satellites within the chromosphere of the Sun, or directly manipulating the Sun's magnetic fields from a distance. We couldn't do this now, even with the proper infrastructure deployment, but it wouldn't take too much scientific advance to give us the capability.

    Finally, Long-Term projects require the limit of what I consider forseeable scientific and technological progress. I can see how it might theoretically possible to either shield material structures against the extreme thermal, mechanical and magnetic stresses prevalent within the Sun, or construct such machines of exotic materials which would be proof against them. I am perfectly aware that such would require considerable scientific advance, on the order of the difference between modern engineering and the engineering of Classical Roman antiquity.

    Clear now?

  4. It would also require materials that may not even exist.

  5. They don't exist now. They may or may not be possible. I will point out, though, that the approach of building a shell or robot out of exotic matter is only one of the possible avenues: scientists now think that it is theoretically possible to embed complex patterns in electromagnetically-charged plasmas, and (even better) we're just starting to learn how to create complex photonic patterns. So the construction machines or robot bodies might wind up being made out of something as close to "pure energy" as you will ever see outside of a pulp sf story. Neat, eh?

  6. Yael Dragwyla commented:

    Actually, Jordan, you've done a great job of making the distinctions between "near-term," "middle-term," and "long-term" technology and its potential applications very clear. There's no harm in speculating about things far in the future. Also, John W. Campbell himself insisted only that stories published in *Astounding* had to accord with what we know *now* about the physical universe and possible ways of exploiting it; when it came to things which, so far, were unknown to science and couldn't yet be proven real or unreal, the sky was the limit. So, e.g., natural gravity had to work in a story like we know scientifically gravity unmodified by anything really does, whereas positing a gadget that could get gravity to do things it could never normally do by evading or transcending physical laws by means of as-yet-unknown principles was acceptable as long as it didn't get ridiculous. When it comes to futuristic speculation, the same is true: we can posit as-yet-unknown technologies and scientific principles as long as they don't fly in the face of what we already know to be true. (An example of the latter would be New Agers claiming that on 12/21/12, the Earth's poles of *rotation* will shift by some huge amount, say, around 45 degrees relative to the plane of the Solar System, and do so within 24 hours, which would require the Moon suddenly ceasing to exist -- the Moon has stabilized Earth's axis of rotation for over 4 billion years -- and, as well, the Earth's surface getting slagged down to the mantle due to the heat released by the sudden change in Earth's angular momentum.) So such speculation is very much in order, as long as it is clearly given which belong to which future domain. Which you have.

  7. Well yes -- one should always be clear in a futurological speculation as to the general timeframe under discussion. There is no way that we could return to the Moon in, say, a month (not enough time to assemble a launch vehicle from existing components) but we could do it (at some peril to the crew) in a year if we had a good enough reason, we could easily do it with reasonable safety in ten years, and I would be very surprised if there weren't significant Lunar settlements in a century.

  8. (the Lunar comments being by way of example, of course).