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)