Reusable space vehicle for long-dwell payload hosting, orbital maneuvers, and downmass operations, and related method

A vehicle, comprising:

• a pressure-fed propulsion engine;
• a first conduit configured to provide a first propellant to the pressure-fed propulsion engine;
• a heat shield wall defining an outer surface of the vehicle;
• a heat shield heat exchanger disposed relative to the heat shield wall;
• a second conduit configured to provide a second propellant to the heat shield heat exchanger;
• a pump located along the second conduit;
• wherein the first conduit is configured to provide the first propellant to the pressure-fed propulsion engine at a first mass flow rate {dot over (m)}1;
• wherein 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
• wherein the second mass flow rate {dot over (m)}2 is substantially less than the first mass flow rate {dot over (m)}1.

A method for in-space and atmospheric reentry operation of a vehicle having a propulsion engine, comprising:

• pressure feeding a cryogenic fuel to the propulsion engine;
• pressure feeding a cryogenic oxidizer to the propulsion engine;
• and
• delivering a coolant to a heat shield heat exchanger disposed relative to a heat shield wall that defines an outer surface of the vehicle;
• wherein the steps of pressure feeding the cryogenic fuel and pressure feeding the cryogenic oxidizer do not involve use of a pump;
• wherein the cryogenic fuel is delivered to the propulsion engine via a first conduit at a first mass flow rate {dot over (m)}1,
• wherein the coolant is delivered to the heat shield heat exchanger via a second conduit at a second mass flow rate {dot over (m)}2;
• wherein the second conduit is not in fluid communication with the first conduit;
• and
• wherein the second mass flow rate {dot over (m)}2, is substantially less than the first mass flow rate {dot over (m)}1.