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)