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)