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)