Really cool concept, and I like that there's a bit of risk going between planets. The only real issue is that the risk mechanic feels a bit isolated, there's not much of a reward to counterbalance it. If you had more upgrades, like weapons or shields that mitigated the risks but also decreased your cargo space, that could open up multiple play styles and allow the player to make meaningful decisions beyond what they'll buy and where they'll sell it. You could also have very lucrative planets that are incredibly dangerous to get to, meaning that if the player wants to trade there, they'll either have to gear-up so much that it's barely worth it, or risk loads of cargo on a barely defended ship.
A few other things worth mentioning:
1. The colour scheme is incredible.
2. You may want a menu that shows planets you've visited and what their prices are so the player doesn't have to remember all of that. This could also be interesting if the prices fluctuate but the menu doesn't update a planet's info until you visit it again.
Bugs I encountered (these didn't factor into my rating, but they're worth mentioning if you plan to keep developing this):
1. There's no way to minimize or exit the tutorial as far as I can tell.
2. The music doesn't appear to loop.