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)