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)