Fatalities per distance isn't a very good metric for safety. Otherwise, you could send 3000 humans 1 light year away and as long as 1 passenger survives, it's

Fatalities per distance isn't a very good metric for safety. Otherwise, you could send 3000 humans 1 light year away and as long as 1 passenger survives, it's safer than air travel per billion passenger miles. Fatalities per trip makes for a better comparison as the vast majority of the risk for space travel, like with air travel, is on takeoff and landing.