I've noticed that when an object collides with anything such as a planet or moon, the impact doesn't heal; it stays red and glowing. This is only on rocky objects, and not on stars and gas giants (the impact disappears rather quickly then). I just decided to bring this up, and wanted to know if this is something to be resolved in the future.
Here's a screenshot of Earth after an asteroid impact. Even after orbiting around the sun, the impact still looks new.