chris@ISM780.UUCP (03/19/85)
Actually the use of explosives on the moon is quite practical. In a recent response to my original lunar colony note, several problems were brought up. They included the distance material is thrown, damage to nearby structures, and safety. It turns out that modern explosives and techniques are suitable for the task. First, distance material is thrown. A little reflection shows that the maximum time for particles to land on the moon is twelve times the time the same particle would take on earth. On earth very large explosions (strip mining bench blasting) can throw sizable pieces several hundred yards. Time of flight is on the order of a second. We won't be using a blast anywhere near as big. Earth explosions (conventional explosives) don't come anywhere near to putting stuff in orbit. The 1/6 gravity of the moon is nowhere near low enough to enable stuff to reach orbital velocity. If we stay under cover for about 15 seconds (but call it a minute to be safe) everything will have landed. Second, damage to nearby structures. There is a book called "The Modern Technique of Rock Blasting" published in the early seventies in Sweden. I read the copy in the UCLA Research Library. It shows methods for doing precision blasting in areas where fragments cannot be allowed to fly about. One picture shows a building foundation being blasted with buildings on either side, literally feet away from the blasts. The text talks about how to minimize ground shake and fragment throw. It is quite practical to blast hard rock within feet of existing structures without damaging them. The text has some amazing pictures that show rock that looks like it has been sawn that has really been blasted. It is possible to control explosives to give very precise results. Third, is safety. There are modern explosives that are shock insensitive to an amazing degree. One result of the nuclear weapons program was the development of explosives to compress the nuclear material that would not detonate during an accident. There is a film that is shown at the Museum in Los Alamos that shows rockets with cargos of the insensitive explosive impacting concrete walls. The rocket is destroyed, but the explosive does not detonate. This explosive is also easily machined, and stores well. It would be safer to transport than the solid fuel rockets used as kick motors on satellites. The nice thing about explosive digging is that you can move a lot of material in very short order. With proper precautions it is no more dangerous than using a catapilar tractor, and much faster. chris kostanick decvax!vortex!ism780!chris