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)