Good start, I got excited when you gave me text popups cuz I thought it was gonna be an FTL like but not so much. I do like that you can only refuel once at each planet in terms of giving players a tough choice but that needs to be communicated more clearly (locking the button only works as an indicator after you've used it; a pop-up wouldn't go amiss).
The map feature is really well done, I love that it's not just zoomed out from the game, but you could lean even more into the difference (change the planets to just circles, make the background a solid colour, etc) and it needs something to dissuade you from just playing completely in that mode (lock the controls at the very least)
There's not much of a game loop at the moment - more choices on the planet exploration would be neat (FTL like morality choices) or maybe reworking the movement to be more involved; it's space, you don't need to use fuel to move in zero G (check out 'Its Lonely out in Space'), and it would be cool to have gravity wells around planets that can help or hinder you. You could add a dash-like warpdrive that does use fuel (since you're going faster than physically possible) that doesn't get affected by gravity but also doesn't update your map or affect your momentum.