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)