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)