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)