The original Sublimator Driven Coldplate (SDC) design sought to provide significant mass savings over a traditional pumped fluid loop by combining the functions of a cold plate and a sublimator and eliminating the fluid loop (Leimkuehler, et. al., "Design of a Sublimator Driven Coldplate Development Unit," 2008-01-2169). The target application was to provide heat rejection for the ascent module of the Altair lunar lander vehicle during the lunar ascent mission phase. However, in order to provide heat rejection for the ascent module during the rest of the mission, it is desirable to keep the ascent module integrated with the fluid loop in the rest of the Altair vehicle. Therefore, we propose an Integrated Sublimator Driven Coldplate (ISDC) that can function as both a standard flow-through cold plate and a Sublimator Driven Coldplate. The ISDC builds on the original SDC concept by adding coolant layers so that it can be integrated with the pumped fluid loop on the rest of the vehicle. This approach provides mass savings by (1) combining multiple pieces of hardware into a single piece of hardware and (2) providing additional fault tolerance without the need for redundant hardware.

In addition to NASA space vehicles, commercial space vehicles may benefit from this technology as well. Paragon has been working with a number of commercial space companies to design their thermal control systems. Due to the nature of the vehicles and their concept of operations, coldplates and sublimators almost always end up being included in these systems along with a pumped fluid loop. The same mass and reliability improvements discussed previously may potentially be applied to these commercial space vehicles as well.

This SBIR could directly impact the current program of record, primarily the Altair Lunar Lander; in particular the ascent module. However, other NASA applications could benefit from this research program as well. For example, the Orion Crew Exploration Vehicle may see similar benefits as those described above for Altair. Instead of an ascent module and descent module on Altair, Orion has a crew module and a service module. Just like the Altair ascent module separates from the descent module before lifting off of the lunar surface, the Orion crew module separates from the service module before re-entering Earth's atmosphere. Alternatively, if Orion evolves into an ISS lifeboat, the vehicles primary mission would be a return to Earth profile in which the Orion stages from the ISS. Because of the analogous arrangement of these modules, Orion may see similar mass and reliability benefits from an ISDC due to combining multiple functions into one piece of hardware and/or strategic location of various components between the two modules and the associated "gear ratios" for launch propellant. Due to the benefits for short duration missions, this SBIR could directly impact the upper stages of small, medium, and heavy launch vehicles as well as boost stages for high altitude orbits. In addition, many of the planned technology demonstration missions will require simple, safe, and reliable platforms in which the ISDC would assist in reducing the weight and complexity.