I understand that every probe launched has been launched into an orbit. The further you want to go into the solar system, the faster it needs to be moving. And everything orbits the sun until it finds a different mass to "capture" it.
But I noticed that Pluto is REALLY far away and the orbit of New Horizons is not a circle nor an elliptical shape and it doesn't look like the probe will ever come back - it will just keep going. It doesn't even look like it is orbiting the sun! How is this kind of orbit possible?
Same with the voyager probes. It looks like they will keep going into interstellar space and never come back. Is their trajectory even remotely some kind of a circular orbit around the sun at this point? If not, how is this kind of trajectory possible?