Not too many months ago, we were watching the news based around Mars and here we are even deeper into space. CNN says that Saturn is about 930 million miles away from Earth (depending on the time of year) so if the Cassini has spent the last seven years traveling the 2.2 billion miles to reach Saturn, asking google, that spacecraft was traveling at 57,701 km/h. It also talks about the 90-minute transit of the rings covering 98,500 miles (158,000-km). That's 105,333 km/h.
Either way you look at it, those are amazing numbers but what's even more amazing is that people are actually building these things that can be launched from Earth with the prediction, accuracy and precision 7 years into the future. That's a long time to wait to see if your calculations were right.