A vehicle configured for in-space and atmospheric reentry operations includes a pressure-fed propulsion engine that uses cryogenic fuel and cryogenic oxidizer as propellants. In some embodiments, the vehicle includes a first conduit configured to provide a first propellant to the pressure-fed propulsion engine, a second conduit configured to provide a second propellant to a heat shield heat exchanger disposed relative to a heat shield wall defining an outer surface of the vehicle, and a pump located along the second conduit. In such embodiments, the first conduit is configured to provide the first propellant to the pressure-fed propulsion engine at a first mass flow rate, the second conduit and the pump are configured to provide the second propellant to the heat shield heat exchanger at a second mass flow rate, and the second mass flow rate is substantially less than the first mass flow rate. A related method is also disclosed.