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)