I beg anybody to rephrase it understandingly with using some units similar to football fields. Is it possible to launch a little cheap rocket with a transmitter just to correct Voyager's position?
We are talking about distances that are so big, there is no comparison that makes sense. Nothing else IS that big. The numbers are literally "astronomical". If you're struggling to wrap your head around it, you're doing it right.
"Space is big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space." -- Douglas Adams
Well, technically, 15km/s IS "more than 10x the speed of sound". An average car, is, TECHNICALLY, more than twice the size of a bicycle.
Also, I don't particularly like the speed of sound for this comparison. Most people think of speed of sound as speed of sound at about sea level pressure, in gas composed of around 78% nitrogen and 21% oxygen and at roughly 25C temperatures. But the speed of sound is highly dependant on the medium and its temperature and pressure. There actually can be sound waves in space (pressure waves in interstellar gas resulting from various astronomic phenomena) and they propagate at very wide range of speeds, typically somewhere between 10 and 100km/s.
The main reason to use "speed of sound" is because important things change when objects travel at little below or above speed of sound in the medium they are in. But this is only useful in relation to the actual medium the object travels through.
One place where it trips people up is when they are talking high altitude airplanes or rocketry. They are talking about something traveling at "X Mach", or "X times the speed of sound" and then I try to figure out if they mean X in relation to the speed of sound up there or the speed of sound at sea level. Just a nightmare trying to use it to convey speeds even within confines of our atmosphere.