Overall Thermal Architecture & Design of the Mars Sample Return Lander Mission

NASA and the European Space Agency are currently planning a Mars Sample Return campaign that would bring Martian regolith and rock samples collected and cached in tubes by the Perseverance rover (Mars 2020) back to Earth for scientific investigation. The Mars 2020 rover landed on Mars, in Jezero Crater, on February 18, 2021. The Mars Sample Retrieval Lander (SRL) would land the Mars Ascent Vehicle (MAV) on the surface of Mars. A Sample Fetch Rover (SFR), in a separate mission, would collect the sample tubes deposited by the Perseverance Rover and insert them in the MAV, followed by the MAV launching them into Mars orbit within an Orbiting Sample (OS) container. The Earth Return Orbiter would rendezvous with the OS, and capture and seal it inside a primary and secondary containment vessel, followed by the OS landing on Earth in the Earth Entry System. The SRL is being designed to maintain the thermal integrity of all thermally controlled components residing in it, including the MAV, lander avionics, the propulsion system, etc. during all flight phases starting from launch until landing and the completion of its mission on the surface of Mars. During cruise, the primary thermal control is achieved by a mechanically pumped fluid loop heat rejection system. On the surface of Mars its environment varies significantly (in excess of a 100 C swing) during a diurnal cycle. There is significant shortage of solar thermal power to maintain the proper temperature range of the SRL, hence its thermal design is very challenging. This paper discusses the thermal design of the SRL during all flight phases by the innovative use of thermal control methods. This minimizes volumetric, mass and power resources to maintain its components and systems within their allowable temperature limits, while surviving the severe environment of cruise & on Mars.