What is the penalty for dying in SWTOR?

There is a timer before you can resurrect, which increases if you die repeatedly in a short timespan.

• 1 death : 10 seconds
• 2 deaths: 30 seconds
• 3 deaths: 2 minutes
• 4 deaths: 10 minutes
• 5 deaths: 30 minutes

Free to play players can only resurrect (call medical probe) 5 times per character.

Your gear takes a minor durability loss as well, so there's a small credit cost that comes from repairing your gear.

I'm not sure exactly how long the time span is that those deaths have to occur in for it to ramp up, though. Note that you have the option to respawn immediately at a medical center, which given the almost non-existent cost of death, can effectively work as a teleport back to the nearest medical center for you when your normal cooldown is up and you don't want to have to run all the way back.

PVP deaths are handled differently, and force you to respawn at a medical center.