I think conceptually you're on the right track with the game. So hope it works out. The biggest issue of most idle games is the lack of actual context/feedback of your progress. When it's just numbers, well, our brains can't actually contextualize numbers beyond a certain (quite low) point. Having the visual feedback of the circles gets around that, and gives that feedback our silly little dopamine addict brains craves.
But I do agree that a speed cap is needed (or you just get the same issue that revolution idle has, where the visual feedback goes away beyond a certain point). Though it does need to be clearly stated to the player that such a cap exists, and most likely make it so the speed button just straight up isn't clickable once you're capped, at the very least.
Then longer term you obviously would want more upgrades etc. to give the game a lot more play time. Because now, yeah, it's like a 10 minute game at most, give or take. I only spent longer because I was resetting to test the weird/buggy behavior. But it's an early build, so expect those to be later concerns to work on. One thing that I was kind of hoping for, but that wasn't the case. Was that the moon would actually rotate about the orbiters. Having some kind of effect on that orbiter. Because right now, the moons are basically just "orbiter 2, but with a variable orbit".