I have had spaceship design on the brain lately, which led me to think about ion engines as sub-lightspeed travel.
If you think of space travel as a marathon, not a sprint, then you also need to think about what people would do to fill the countless hours, days, weeks, etc. Think of it as the longest road trip ever.
If you had a hyperspace jump drive that allowed FTL travel, think of the adventures you'd miss along the way.
So how fast (or slow) are we talking here? Well when you figure that the speed of light is 300,000 km/sec, then the paltry 20-50 km/sec of an ion engine seems abysmally slow.
Currently built with a lifetime of approximately 20,000 hours, ion thrusters could burn for about 833.33 days or 2.28 years.
And if the exhaust velocity reaches its maximum range of 50 km/sec or 180,000 km/hour (111,846.5 mph) that means you could travel 3,600,000,000 km (2,236,936,292 miles) in the lifetime of that particular ion engine. Even if you could only achieve a "slow burn" of 20 km/sec (44,739 mph) that would still carry you 1 billion 440 million miles. Maybe you could squeeze a few more million miles out of it since you're not burning as hot.
If the speed and distance are too much to wrap your head around, think of it in terms of scale.
The circumference of the Earth is 24,901 miles. Rounding that up to 25,000 miles, you could still circle the planet 57,600 times. But who wants to only drive around the block when you can get on the open road and really let the ponies run?
The moon is 238,900 miles away. You could get there in just a little over 2 hours.
It took Neil Armstrong over 4 days.
Let's say you wanted to swing by the future colony on Mars, which is about 35 million miles away.
It would take you 13 days. Ok, that road trip is starting to get wearisome. That's like driving from LA to NYC and back.
But let's say you have a spacious RV with lots of room to stretch out and all the high-tech, time-suck gadgets of a deep-space faring civilization. And like the best road trip mix of tunes ever!
You are going to push to the very edge of our solar system - 7 billion 440 million miles.
You'd get there in 7.59 years and you'd have to change out your engine 5 times. Let's hope you have James T. Kirk's Triple A card.
By the way, instead of a little hula girl on your dashboard you have a Buzz Lightyear bobble head.