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)