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)