Our car has three parachutes.
The high speed and medium speed parachutes work off our nitrogen tank in the car. I will get to the parachute operation in a minute. First, the nitrogen tank feeds all air systems on the car, transmission and parachutes for example. When we are looking at the system last year the big what if came across - We added a strorage tank in the back of the car which is fed by the nitrogen bottle. It goes thru a one way valve - so if we had a catastrophic trans failure that cut the air lines we still have a charged cylinder in the back of the car. It was enough air at 120 psi to fire the chutes 10 + times.
Now the high speed and medium parachutes have a seperate hole for the pilot which is ejected by the air cylinder which pull out the main parachute. The last chute which we named the "Oh Sh*T" chute, is manual release only with no pilot but is ejected by a spring.
I can provide pictures of our setup if you like.
JonAmo