A turbopump including a rotor having a first face and a second face and being characterized by a rotor axial height between the first and second rotor faces and by a rotor diameter. A rotor housing includes bearing surfaces for supporting rotation of the rotor, includes turbine inlet and turbine outlet ports and pump inlet and pump outlet ports, and includes pump and turbine fluid sealing surfaces. A plurality of turbine blades of a turbine blade axial height, and a plurality of pump blades of a pump blade axial height, are disposed on a face of the rotor. The turbine blades and pump blades can be together disposed on the rotor first face. Further or alternatively, a turbopump axial height including rotor bearings, turbine blade and pump blade axial height, and rotor axial height, can be less than rotor diameter.