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)