Quote from: docmordrid on 01/12/2017 05:56 pmThe cutter above is often used to cut an arched tunnel, like a quonset hut, but there are other heads used for profile cutting such as squaring off. There are vertical versions for boring shafts. The head motors are hydraulic, so power can be whatever you can run the pump with; electric, or an IC using ISRU methalox. Possibly alcohol + GOX using a different ISRU process.Gah, combustible fuels in an engine are just TERRIBLE if you're doing ISRU. They use about an order of magnitude more power (wasting like 90% of the energy) than electric, and since you have to bring along oxygen (and usually want to reclaim the water in the exhaust), usually don't even end up lighter even compared to battery power.I wish that idea would just die.
The cutter above is often used to cut an arched tunnel, like a quonset hut, but there are other heads used for profile cutting such as squaring off. There are vertical versions for boring shafts. The head motors are hydraulic, so power can be whatever you can run the pump with; electric, or an IC using ISRU methalox. Possibly alcohol + GOX using a different ISRU process.
Just stating the options. I agree with electric, unless you're boring some distance from high power generation. You're not going to carry a reactor or 200 m^2 of panels around. Solid oxide fuel cells maybe...
Cutters work well enough, as long as whatever you're boring through is solid enough to be self supporting.. Otherwise you may need a boring machine with shield and have to erect support ribs/marscrete behind you. At least not too much water to deal with.. depending on where you're going..
If Musk were to use some kind of microwave drill thing to bore tunnels with, perhaps it could also microwave-sinter together the material forming the walls of the tunnel, to make it more self-supporting.
When Elon Musk goes into tunneling, as he is claiming, then I expect some novel method used. I strongly doubt that he would start a company using conventional boring heads. On earth those heads or at least the cutting implements are exchanged very frequently for wear. It would be very advantageous to have a method that reduces need of maintenance. On earth and much more so on Mars.
Well, I was thinking there was the mining/ISRU aspect to this as well. Perhaps a tunneling machine would eventually evolve into a mining machine, which could extract ore and maybe even feed it into a smelter. The article shows a large-sized machine as the current state of the art, but there's no reason that a smaller machine couldn't be used to bore large tunnels, if it had the right technology. I was thinking that microwave boring machine could be small enough and light-weight enough to be transportable to Mars, where it could be used to bore much larger cavities - although using the microwave approach for extracting ore might take some re-thinking (maybe with microwaves you could somehow bore and smelt at the same time?)And at the same time, a microwave-based approach might offer the chance to disrupt the marketplace and take business from the higher-cost established players.
Explosives work well, but drilling those holes would imo require manpower vs. automation. Drills get frequently stuck badly in holes and can require a frustrated artistry to remove.
Quote from: TripD on 01/14/2017 11:21 pmExplosives work well, but drilling those holes would imo require manpower vs. automation. Drills get frequently stuck badly in holes and can require a frustrated artistry to remove.Explosives are just a form of energy. On Mars they would probably need to be made from atmospheric nitrogen, and in some sense eventually come from solar energy. So might as well use the solar energy directly to drive equipment. Bringing the explosives from Earth would likely be too expensive.
Quote from: lamontagne on 01/14/2017 11:57 pmQuote from: TripD on 01/14/2017 11:21 pmExplosives work well, but drilling those holes would imo require manpower vs. automation. Drills get frequently stuck badly in holes and can require a frustrated artistry to remove.Explosives are just a form of energy. On Mars they would probably need to be made from atmospheric nitrogen, and in some sense eventually come from solar energy. So might as well use the solar energy directly to drive equipment. Bringing the explosives from Earth would likely be too expensive.I was not promoting bringing explosives from earth. I was bringing up the issue of having to drill many holes for any type of explosive. Rocks chip and pin the bit quite frequently. You literally have to outsmart the bit from time to time to retrieve it because shear torque will not work.