As the Probe enters the Titan atmosphere, it is subjected to a severe
deceleration at an altitude 
250 km that
can be as high as 16.1 g.
A parachute is deployed at a speed near Mach 1.5, marking the
beginning of the descent phase (time = 
).
After the Probe slows to subsonic velocity,
the heat shield is jettisoned (at 
+ 30 s) and the
PRL is established for transmission of data back to the
Orbiter (no later than 
+ 150 s).
The large initial parachute is released at 
+ 15 minutes and
replaced by a smaller drogue parachute in order to
decrease the descent time.