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)