If you’re talking about leaving the galaxy, that velocity doesn’t count. Everything in the galaxy shares that velocity (more or less), so it can be ignored. The only velocity that counts is that which is relative to the center of the galaxy.
That was my point, re: the solar system velocity.
The solar system velocity does count. It’s only shared by things in the solar system, not by anything else in the galaxy. Voyarger 1 is going roughly towards the Solar apex (the point on the sky the Sun is headed toward) so you can add its velocity to that of the solar system to get its net galactic velocity. (It’s not going exactly towards the Solar apex, but it’s close enough for a first approximation.) Voyager 2 is going in another direction, so the velocities can’t be simply added like that. It still shares the Solar velocity, though.
How long before Voyager 1 gets shredded by cosmic rays into a mass of powder? In that state, would Voyager be able to hold itself together with self-gravity, giving the appearance of a solid craft?
Mm, my misunderstanding, then.
I feel like I need a vector diagram …
Thank you for the links!