space construction continued

Okay, so yes, I have more ideas about using NEA asteroids to do construction in space of a space farm, a space university and a space tree farm.

First, with respect to turning asteroids regolith into cinder block sized bricks. There needs to be some kind of adhesive that keeps the regolith powder and small bits together. I did a bit of digging and found that a one-compound epoxy can be made up of carbon, hydrogen and oxygen; all things that can be found in the C-type asteroids. So one processing stream from the asteroid is to transform the carbon, hydrogen and oxygen into a usable epoxy. Further reading has shown that this epoxy could also be good at radiation protection. 

The next problem I found to solve was how to compress a mixture of epoxy and asteroid regolith into a cinder block shape such that it is fairly evenly mixed and holds the shape correctly and is structurally sound all in microgravity. What I came up with is to have a box perhaps 1.5 the size expanded in all directions of the end result standard cinder block dimensions; put into this box the amount of regolith needed to make the brick, and then from the top and bottom center, inject the epoxy such that it meets mostly at the center of the brick. Then, for a specific duration, spin and contract the walls of the block form such that the epoxy mixes with and expands outwards to the extremities all while the block is being compressed to its final form. Then the brick is moved out to an oven that uses a direct thermal energy transition from the sun light receptors to bake the brick for the appropriate amount of time.

If the above epoxy producing and then using and asteroid regolith insertion into the form can all be automated, this could create the millions of bricks that would be needed for the different space construction projects I have outlined in previous posts.

My suspicion is that getting this to work will require a lot of analysis and testing in a microgravity environment, so I would propose a small LEO station that can hold 2-3 people with all they need for two week stays and of course all of the equipment needed to do both the engineering and the science of getting the right mixtures and process to create asteroid regolith bricks in cinder block shape and size.

With respect to the space tree farm itself, I did a bit of math to determine the structure and have started simply with the steel frame made up only of the steel sheets. I do not know if further bracing is required as there will be 1m of regolith bricks affixed to the outside and 1m of regolith bricks affixed to the inside and 3m of 2 parts regolith and 1 part Earth soil on top of the 1m of regolith bricks on the inside. And plus there is the air pressure inside and that the whole cylinder will be spinning. In any case, I found that the curved surface area of the cylinder is 6.3 million square meters, and if the asteroid processing factory create 2m by 2m 4mm sheets of curved at 500m radius steel panels, 1.5 million of such panels would be needed.

The two ends of the cylinder would also need to be steel covered, so again working with 2m by 2m x 4mm flat panels, around 394000 of these panels would be needed.

These are large numbers, but if the asteroids can provide all of the metals and carbon and hydrogen and oxygen, it would just be a matter of continually processing the asteroids until what is required has been obtained.