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)