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)