From: henry@spsystems.net   
      
   In article ,   
   John Buehler  wrote:   
   >4. The components that are being replaced appear to involve using a   
   >tool that is the equivalent of a cordless drill.  In order to keep the   
   >astronaut from rotating in reaction to the torque of the tool he's   
   >using, there is a tether or some sort to help keep him in place.  Why   
   >aren't the tools and fasteners designed to work appropriate to the   
   >environment?  Is this just a matter of cost?   
      
   No, it's because restraining astronauts against tool torque has turned out   
   to be a very minor problem.  They need to be restrained *anyway* to work   
   effectively; it's just not possible to do anything much while floating   
   loose (that was one of the lessons of the later Gemini spacewalks).  So it   
   simply makes sense to stick with orthodox fasteners that work well rather   
   than inventing something new.   
      
   In the early 60s there was a lot of work on things like torqueless power   
   screwdrivers.  None of it turned out to be at all useful.   
      
   >An immediate solution that springs to mind for a lot of this is to   
   >have infalatable bags surrounding the trusses and other 'exterior'   
   >components of the station that need to be reached.  It would provide   
   >for a lot more room to move around, and would permit maintenance of   
   >the entire station without any spacewalks.  I'm assuming right away   
   >that this idea has major flaws to it...   
      
   Unfortunately, providing those bags with protection against space debris   
   and micrometeorites, temperature control, adequate ventilation (which   
   can't be taken for granted in free fall the way it can be on Earth), etc.,   
   is not a small job.  The idea is not ridiculous but it's not nearly as   
   simple as it looks.   
   --   
   "Think outside the box -- the box isn't our friend."    |   Henry Spencer   
                                   -- George Herbert       | henry@spsystems.net   
      
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