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)