1.in order that- = so that- ,No difference at all.
e.g.I got up early in the morning in order that / so that I could catch the first bus.
2.in order(not) to + do sth = so as (not) to do sth,No difference at all.
e.g.I got up early in the morning in order to/ so as to catch the first bus.
3.In order to catch the first bus,he got up early in the morning.
(Only " In order to...' is acceptable in this case.)
At the beginning,we can't say," So as to" catch the first bus,he .
Got it?