upsides to making a portal to heaven  
    to   build   the   factory  there   
  
                                          
 first of  all, real  estate:  the highly 
 fractalized  geometry  (not  proven  but 
 likely to be  the case)  implies  almost 
 unlimited room; even if the  portal tech 
 would  be  stolen,  chances  of  running 
 into a  competitor  is  close  to  none, 
                                          
 secondly,  the  resources:  heavens  own 
 alchemical  properties   (proof  exist!) 
 makes  most  base materials  easily  and 
 readily available.  once  the  molecular 
 movement patterns are  mapped  out,  any 
 compound   can   be   created  virtually 
 without                            cost. 
                                          
                                          
  
   downsides to making  a  portal  to   
  heaven to build  the factory  there   
  
                                          
 current portal  tech  takes some  energy 
 to  hold open, which isn't a  problem in 
 itself. test results however  has  shown 
 that without  an active tether, heaven's 
 time flow  breaks down completely.  even 
 a momentary  fluctuation  of  the portal 
 would   render    all    remote   assets 
 practically  lost.  much  care  must  be 
 taken  to   maintain  portal  stability. 
 (one option  could be  several  portals)