Tesla's new Roadster hung almost upside down 65 feet off the ground, let go, and caught itself before it landed. The only thing it used to stop the fall was air. Without the thrusters, that's a bad two seconds. From 65 feet, about six stories, a car hits the pavement doing roughly 44 mph. Nobody was inside. Elon said the car drove itself for the demo "to make sure we don't kill anyone." Watch the readout in the bottom left as it drops. It jumps to 3.1 G at 31 feet as the thrusters fire, which…