You may already know this. I clearly didn’t.
Yesterday I had been fooling around in space for some time. I eventually found myself aboard a freighter for sale, which I didn’t buy.
I flew off to buy some frigates, then went back to the freighter. It was late, and I was tired. In the freighter docking bay, I jumped out of my ship to save the game, then hit the buttons to shut the game down.
It was only as the closing screen was fading, I realised that it said “your game was last saved 51 minutes ago”. Too late - I had already pressed “close”.
OK, I only lost an hour of play time - but I’d bought some nice frigates in that hour - and now they’re gone.
So be warned - leaving your ship while you’re on board someone else’s freighter will not save your game.