Light exerts pressure on anything it hits. So one of the methods I’ve seen involves unfurling a light sail that’s hundreds of miles in diameter when you get near your destination star and the light pressure on your sail will slow you down. Don’t know about 0.80c. You might need a considerably larger sail, or you’ll just fly right on by.
So... where would you keep that light sail, in the glovebox ? How many crew members would it take to unfurl it ?