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)