Even .99c isn't going to do it for you. Time has slowed down on your ship to only 14% of earth time, which will seem like you're living a long span (to the folks back home), and you'll live long enough for an otherwise impossible journey; but to you, subjectively, everything will seem quite normal.
Here is where I get confused. The spaceship is travelling .99c relative to the earth. But that means also the Earth is travelling .99c relative to the spaceship. So why doesn't that mean time on the earth slows down to only 14% of spaceship time, rather than the otherway round? What decides which body gets the "time bonus" when both are actually moving the same speed relative to one another? Where is the object of reference?
Okay, so I only live to be 500 years old, how do I slow the ship down? I guess I could smack into a comet or some other debris, that would slow me down.