I worked for the company that made those thrusters. They also made the thrusters for the moon lander and bunches of satellites. All of those thrusters had a life measured in seconds. The shuttle thruster has to last for the life of the shuttle.
The nozzle and injector plate are made from niobium. Neat stuff. If you touch it, no matter how clean your hands are, it cracks when it heats up. They learned that the hard way. Niobium has an affinity for almost everything and has an impressive number of steps in the refining process to produce pure metal. The injector plate is about 4 inches in diameter and has 1012 holes drilled in it.
If I remember right there are 38 thrusters on the shuttle and every one has a different nozzle profile to fit the body profile.
The shuttle is the only plane that was tested at high speed first! Other than the low speed drop test that was done from the back of a 747, the shuttle first flew when it landed after the first flight. There is a period of time around Mach 7 where the controls are not very stable and the shuttle is held stable with no change in direction through that period.
Oh, and it's a dead stick landing with no chance of a go-around.
I still want to fly in it!
