REM@MC.LCS.MIT.EDU (Robert Elton Maas) (02/17/86)
One major problem with current methods of putting humans in space is that we don't leave them up there. We send up 7 or 8 people, they stay up a week or two, then they come back down, and we have to send them or others up again later for another week or two. If we had permanent habitat in space, each manned launch would permanently add crew to space, and by now we'd have over a hundred living and working in space around the clock throughout the year. Now that there is question as to the safety of STS, and it may be a long time before we can build a replacement, maybe we should adopt a different overall strategy for bootstrapping in space: Cut back on use of STS to reduce mean time before next failure, i.e. to stretch out the lifetime of STS (like if you never drive a car it may last 20 years before it wears out). Meanwhile, convert half the ICBM launch vehicles into orbital launch vehicles, and use them to launch equipment for establishing a remote-control mining and processing facility on the Moon, and a mass driver for tossing processed materials into trans-Earth orbit. Also launch lots and lots of space tugs for catching the tossed material and bringing it into LEO. Mostly this lunar material will be bulk materials for forming walls of pressurized cabins, and oxygen. Also launch enough tools and docking collars and other equipment to convert those crudely-processed materials into true pressurized cabins. Manned STS launches can be used to do final fabrication and checkout of those pressurized cabins. Once several cabins are working, leave volunteer workers in space as the STS orbiter returns to Earth; like 8 go up and 2 return, for a net increase of 6 in space habitat each launch. Once the first permanently habitated set of cabins is up there, that team can have total manned responsibility for final fabrication of additional cabins, so that never again do we have to send a crew to space and also return them all. If any task in space needs a human on site, the existing space-based crew can be trained by remote instruction to do the task, after all communication is a lot cheaper than moving physical bodies around. We can then suspend STS launches completely until such time as a large payload needs STS or we have habitat ready for another crew to move to space permanently. Occasionally somebody will want to return to Earth, and we can simply wait until the next upward crew, as there'll be plenty of space available on STS on the return trip. Initially I would suggest space-based habitat consist of many separately pressurized cabins, with only two people in each, and with several spares under initial pressure-holding tests but not yet occupied. Then if one springs a leak, at worst two crew will be lost, but likely the two will have time to rush into spacesuits, move to other cabins, and bunk up with three to a cabin until one of the new cabins currently under test is ready for occupancy. Regarding making materials for walls of pressurized cabins: The Moon has an advantage for processing aluminum (about 20-30% of lunar soil if I remember correctly) and other materials. You can melt it right out in the open without worrying about Oxygen reacting with it or Nitrogen etc. mixing in with it. It should be easy to dig out a shallow flat area, pour melted aluminum into it, let it cool, and have a nice slab of aluminum ready to toss out into space. (I'm not saying the engineering will be trivial, but I see no need for advanced AI or 5th-generation computers or new science or anything else except the determination to go ahead and to spend lots of money to fund further experiments on loncrete and other applications of lunar materials and good engineering to turn those experiments into practicality.)