How about an option to lock trans-newtonian tech behind surveying a ruin on Mars?
It always felt weird to me how cheap the tech that lets you break the basic rules of physics is, so I always waited until I colonized Mars with conventional tech to research it. In my mind, my guys find Precursor ruins there that can be reverse-engineered to understand Trans-Newtonian physics. Its a well-worn trope, but a good one.
Of course, that would necessitate making troop bays Conventional tech.