How Far Away is Far?

Titan is 1.2 billion kilometers away. If we went the fastest any human has ever gone. (39937 km/h) It would take us 1252 days to reach titan at that speed. That is almost 3 and a half years one way. In 1968 a projected named Orion showed that humans could possibly build a ship that could go 1000 km/s. This ship would use nuclear explosions to propel itself. At that speed it would only take 15 days to reach Saturn. That ship would cost 3 Trillions dollars. And spend over 20 years to make and develop. But there are other options than our current most powerful rockets, the Saturn V.