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)