All posts by tribble

MegaStructures and Human Evolution

We all know reasons for human expansion into space:  preventing human extinction, garnering resources from beyond Earth (rather than tearing the Earth up),  raw human curiosity, helium3, solar energy, enabling the instantaneous woldwide downloading of funny cat videos, .etc.  I’ve though of another.

Judging by the nastiness of humans to their brethren, we need to be able to isolate  breeding populations of humans from each other so that they may evolve into something better/nicer.

A population in a hazardous, potentially lethal environment is just what spurs natural selection.  The individuals MUST work together or perish.

We’ve always been a self-competitive specie – fracturing into smaller tribes and migrating for food, or room, or just to get away from the assholes who run things.  Now we’ve run out of room.

We go into space, or we choke in our own waste, like yeast in beer.

Sorry about the gap … (mind the gap)

Many of you know that this blog was spammed…

… it has taken me a long time to get over it and do something about it.

…the anti-span software plugin for WordPress seems to be handling it, now.

Work on the BuckyBot has continued.  The prototype crawls now.  I’ve been working on the extruder.

The main impediment has been a disastrous water-leak right over my RepRap printer – rendering three stepping motors dead.  But, recovery from that is almost complete, now.

In the Winter of ’16 we plan to go to crowd-funding, barring other developments with the program.

Re-vamped web pages are underway for .


MegaStructures Found by Kepler Telescope ?????

MegaStuctures in orbit may account for the regularities (or irregularities, depending upon your perspective)  in the light curve of a star – as measured by Kepler.  Here is a link to a story in The Atlantic:

For the more scientific of you, here is a peer-reviewed paper describing the light curve of KIC 8462852 somewhere near Cygnus:

Maybe Bucky, like Elvis, didn’t die … he just went home ….


We have discovered that the GPS correction data for the StarFire navigation system is now free.

Therefore, we happy few here at BotHeads are investigating hacking its broadcaster (INMARSAT) to add differential GPS to the BuckyBot.

Maybe we’ll have it done by next St. Crispin’s day.

Will welcome any help.  Frequency is around 1.53 GHz.

Will a GPS antenna/receiver with a new SAW filter work, ya think?

Does anybody know where I can get a SAW for 1.53 GHz? GPS SAW’s haven’t the bandwidth to get up there…

MegaStructures #3 : Convective Turbines

Go to this Wiki for a better explanation of this concept than I can provide here:

Basically, build a really tall hollow cylinder, surround the base with solar collectors that heat the air.  Put turbines in the base or in the tower to generate electricity from the updraft.  Here’s a picture:


The key to the cost is the initial building cost.  Sounds like a job for BuckyBot!  I also think a more hyperbolic profile would be more efficient — which buckybot can provide.  The taller, the more power, and the bigger the collector (delta T) the more power.

I’m exited about the possibilities of this.

Go to Google images and search on “solar updraft” to see the myriad of thinking about these.  The simple geometry required seems a perfect fit with BuckyBot.

Some words about Foundations

Some have asked me about the building foundation for a megastructure, as in:  “wouldn’t the foundation need to me massive to support the weight?”

My first reaction was, no, but it spurred me to make some calculations to make sure.  This is the initial result.

For the 1 Km dome, I postulated a simple foundation consisting of a ring footer, or series of posts, or just the dome structure sitting on the ground.  I reviewed some foundation design from some civil engineering texts.  The worst case appears to be clay soil.

Clay soil will support about 15 tons per square foot (sorry, but it was an American text … it works out to 147,000 Kg per square meter).  So, if the load on the foundation is less than that, it’s stable.

A one kilometer diameter dome has a circumference of 3,140 meters.  So, I calculated the area of different foundation widths using that numbers.

I assumed that the weight of the dome is a function of the external area of the dome (that there is no supporting inner structure — its structural integrity is only dependent upon the shell of the dome).  I then calculated the ground pressure for a series of areal densities.

Areal density is how much the shell of the dome weighs per unit area.  A really, really lightweight structure might weigh ten kilos per square meter, a heavier one might weigh one hundred kilos per square meter, and so on.  If you multiply this areal density times the surface area of the dome, you get how much the dome weighs (for each different areal density).  I went from 1.0 Kg/m2 to 1,024 Kg/m2, and this is what I got:

Foundation plot


Turns out the foundation on clay soil only needs to be 1 meter wide at an areal density of about 350 Kg/m2 (assuming the foundation is a concrete ring on the ground).  This is quite reasonable.  At an areal density of 1024 Kg/m2 the foundation width is still only 3.6 meters.

So, no, the foundation is not unreasonably large and massive for a 1 Km dome.

Megastructure #2: Sequestration of Bad Stuff

The quick thought here:  a big dome around Chernobyl built by buckybots.  BuckyBots might be able to go in autonomously and build a dome -like structure over the stricken reactors to reduce the liberation of fission products to the atmosphere.


Think of an autonomous armored personnel carrier containing a bunch of bots.  It drives up to a predetermined  geolocation, lowers its ramp, and out swarm a bunch of buckybots deploying to their build positions.   Shades of Wall-E…

Even a semi-permeable megastructure around the sight would  significantly reduce downwind contamination.  If made from stainless, it could weather the test of time — at least until the fission products have decayed significantly.  Maintenance for longer periods is more of a sociological problem than a technical one.

Of course such a structure does nothing to address the subterranean problems, such as ground-water contamination and leaching of radioisotopes and radionucleides.

The same principles might be used to sequester hydrocarbons and CO2 produced by the uglier results of man’s fossil-fuel endeavors.

I hope you all realize that the disaster was caused by a bureaucrat asserting his “authority” over the reactor operators (who resisted doing the stupid reactor test their boss insisted on doing).

I saw that kind of stupidity all the time during my brief stint in the nuclear industry.

Maybe a sequestration megastructure is what we need over Washington D.C. ?


Megastructure #1: Solar H20 Distillation

On the homepage we list this as the first anticipated use.  Let me explain.

We’ve long known that one could distill fresh water from foul using an enclosed space with transparent walls.  It works like this:

1. Construct a sun-transparent cover over some container of foul water.

2. Let the sun heat up the water… creating water vapor in the enclosed airspace.

3. Continue the process until sunset.  During the dark hours the transparent surface will cool to or below the dew point.

4. Fresh water condenses onto the inside surface of the transparency.  If angled correctly, the growing dew drops enlarge and slides down the transparency.

5. The fresh water pools at the base of the inner transparency surface.  If one arranges a catch-basin appropriately,  fresh water is collected.

Here is a graphic I pulled off the net that illustrates the principle:


Imagine that the contaminated water is a big salt flat, or a salt lake,  or a big contaminated cooling or waste-water pond.

If we build a hemispherical dome over it we might be able to reclaim the water.  We will study on just how to do that with buckybots.  Transparency might use glass fiber and clear epoxy as the build materials.  Optical epoxy is typically UV-curable.  BuckyBot can handle that by incorporating UV LED’s timed with the extruder.  My Russian friends at SETi  (not the alien hunters…) can provide.

The receiver is simply a hollow torus around the inside rim of the dome.  The dome is perforated along the bottom rim to let the water flow in freely.

We are considering using one of the dry lakes in the western US as a site for the 1Km dome.  Some of those are seasonal:  a foot or two of water during the winter, drying to a flat salt/alkali surface in summer.  So, if we ever get to the 1 Km dome, this may be our first purpose-built demonstration project.

A few words about construction materials…

The first structure built by BuckyBot is planned to be a 2-meter hemispherical dome built out of plastic (maybe PLA, maybe ABS) using the standard glue-gun extruder principle.  Don’t think that our one-kilometer dome will be made that way.

As we progress in structure size we intend to progress in material as well.  The extruder design can easily incorporate monofilament fiber as a reinforcement fiber in an extruded plastic matrix.  Glass, metal, and carbon filaments all come to mind.

Next, we might use sintered or welded wire of aluminum, steel, or, finally, stainless steel.  If we want to build structures to last we’d best use stainless.  UV and ozone degrade plastics.  Aluminum and carbon steel corrode.  Stainless just endures.

The Hackaday Prize has a couple of welded aluminum projects… maybe we’ll steal from them.