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)