Normally, the game will delete your autosave and stop you from continuing if your ship is destroyed. To get around that restriction, you can find the game folder in Windows and make a copy of the continue.sav file on your desktop or some other handy location. Then if you play the game and lose your ship, you can simply copy that spare file to your game folder and try again. You can repeat this as often as you like, but remember to always use caution when manipulating such files or you could lose progress unexpectedly.