I think you're speaking of space while I'm speaking of spacetime, that's our disconnect. Spacetime is not flat. It can’t be: Einstein’s general theory of relativity says that matter and energy curve spacetime, and there are enough matter and energy lying around to provide for curvature.Gravity is not a detectable force like electromagnetism. It's a phenomena caused by the curvature of spacetime near massive objects. It can only be detected by it's effect on mass and electromagnetism. Being all by yourself in flat space there is no way to orbit anything. Applying acceleration in any direction there means you will continue in a straight line until you encounter curved space again. Even that will not happen unless you can go fast enough to beat the general expansion of the universe.