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)