Travel

3-D Printed Object with supports

Marc made a thing using a 3-D printer. It looked kind of like a cross between a glass cathedral and a radio transmitting tower. It was roughly triangular, about 4" x 4" x 6". Most of it was composed of whisker thin struts about a centimeter long. I'm looking at this thing and I'm wonder what kind of drugs he was taking that enabled him to design such a complex and elaborate structure, whereupon he points out that all of the spindly stuff is just an artifact of the printing process that will be trimmed off. The part he was intent on was a roughly rectangular piece about a quarter of an inch thick. It was set at an angle because that was the only way it would fit within the printer's working area.

This morning someone on Quora asked if you make an electric motor using a 3-D printer. As far as I know you can't, at least not yet. We have printers that print plastic and we have printers that print metal, but none that will do both. Also printing plastic can achieve much better results than printing metal. I surface of the part Marc printed was perfectly smooth to the touch and it was printed on an angle. If it was printed flat I could see that any printer could make a smooth surface, but for it to be this smooth at an angle, the resolution must be pretty dang high, better than one-thousandth of an inch. The resolution of one metal printer I've heard of is probably somewhere on the order of a tenth of an inch.

All of which reminds me of a science fiction story I read a long time ago about Joe's Garage where they repaired spaceships. It was a going concern. Customers brought in their broken rockets and space tugs and Joe's gang would fit new rocket motors or replace the fuel tanks or clean the air filters, and everything went as smoothly as any kind of repair operation ever does. Until some aliens showed up with a broken spaceship they wanted fixed. This would not normally be a problem, aliens showed up with their weird alien ships ever once in a while and Joe's gang would hammer out some kind of fix.

This ship however was a different kettle of fish. The started looking at it and quickly realized that it a couple of orders of magnitude more sophisticated than anything they are worked on before. In fact, the ship wasn't built in the conventional sense, the whole thing was printed on the molecular level. Any repairs they did would have to done using the same technique, but nobody at Joe's, and nobody they knew, knew how to do this. So they chloroformed the aliens and scanned their brains to find out how to do this. Once they had the information they built their own molecular printer and fixed the ship. The aliens weren't too happy about being chloroformed and having their brains scanned, but they were happy that their ship was fixed.

So now I'm thinking about space travel and how if you have a ship suitable for long distance travel, you really don't want to be bringing down to the ground. That just complicates the situation. It's better to use a craft specifically designed for the purpose to get off a planet and up into orbit, or from orbit to the ground. But what we really want is a space elevator. Haven't heard much lately, but I expect that eventually some whiz kid will come up a material that is strong enough to take the load.

The problem with having a tether out in space is that it is going to subject to strikes by micrometeorites, which means the tether is liable to break. I can see two ways of dealing with this problem. One is to run repair crew up and down the tether on a regular basis, patching all the holes made by micrometeorites, and the other would be to replace the tether on a regular basis. It kind of depends on the available technology.  Patching something on the molecular level would be a bit of a trick, kind of like what Joe's crew did with the alien spaceship. Replacing the tether on a regular basis might be a better solution, especially if you could recycle the old tether for use as material for the new.