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)