Jupiter is between 4 and 6 AU from Earth. So at the speed of light it would still take over half an hour to get there. It’d be a dull game flying anywhere at sub-light speeds.
It’s been over thirty years since I played Frontier, but I think you could accelerate the in-game time. So you didn’t have to sit still for hours to get to Jupiter. For your character, that time did pass.
Yup that’s how it worked - there were several time advance multiplier buttons. Anytime an enemy ship engaged you it forced you back to 1x time, annoyingly
