Minor bug(?): if you do anything else while space flight is going on, it interrupts it and you lose the fuel and SM. I know it's being interrupted since you are going back to go milk and massage her, but I think it's deleting the fuel and SM when it happens.
Also feels like the game should switch away from "Yuri's laying down, her tits splayed to either side, waiting for you to massage her back... and perhaps a little bit more." once you're in space and there's nothing to lay on.
Don't be silly, of course there's something to lay on. She's laying on her tits.
And there is gravity by that point, from a previous upgrade.
As for the bug, that's intended behavior. You don't lose the fuel and SM, though, it just acts as if you've returned and collects it for you. This is no longer the case once you get the "remote work" upgrade, after which you can continue to do other things while spaceflight is happening (though any produced fuel won't go to the ship and will be lost instead).
