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)