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)