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)