please put an "exit game" button in the pause menu.

[Bwixie]

it takes way too long to exit the game. first you have to leave or revert your current flight, exit the sph or vab, quit the current save, go back to the main menu from the save menu, then click exit game.

or alternatively: alt-f4 anytime and risk losing progress. :/

[Jupiter3927]

Hit [F5] to quicksave when possible.
Then press [Alt-F4] to close.

When you start the game up again, it should be right where you left it.
If not, hold [F9].

[Chibbity]

What he said^

Manual save then Alt+F4.

[Manwith Noname]

https://forum.kerbalspaceprogram.com/index.php?/topic/174445-151-malahs-quick-mods/

[Toastie Buns]

Alt+F5
Alt+F4
named saves ftw

[Bibi Maghoo]

+1, it is really annoying not having an exit game option. I can control, alt, tab and close anything the same as F4, but it is not the same as having the basic option included in most titles.

[alan85224]

HOW do you play KSP and not know alt+f4. I do that all the time, usually its preceeded by something catastrophic