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)