When you go bankrupt

[Suicide Junkie]

In tactical combat, you can give orders to ram a star, planet or wormhole. You still require movement, but your ship does explode and require no further maintenance...
In any case, you'd need engines to suicide your solo ship, otherwise you'd stay in orbit.

If you've got engines, you can fly into the nearest black hole or ship-damaging storm, but you could also just return home and get repaired/resupplied/scrapped.