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)