Devices, methods, and systems for providing a solid grain fuel for a hybrid rocket. In one embodiment, the solid grain fuel includes a housing having a length extending between a first side and a second side. The housing defines a central axis and a bore extending from the first side to the second side. The bore of the housing extends with a helical configuration along the length of the housing. Further, the housing includes multiple segments configured to interlock together to form the bore along the length of the housing.