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)