Planetary and Lunar Environment Thermal Toolbox Elements (PALETTE) Project Year Two Results

This paper summarizes the technology development progress made through year two of the three year JPL PALETTE project, which is funded by the NASA Game Changing Development (GCD) Program. The overarching goal is to ensure that a full palette of flight-ready (high TRL) thermal �toolbox� elements is available so that engineers can create passive, ultra-isolative thermal designs for science instruments on a variety of carriers in lunar/planetary extreme environments. The PALETTE technical focus areas include enclosures, radiators, MLI, thermal isolators, gimbals, thermal switches, thermal transport devices, thermal storage devices, deployables, and low heat loss feed-throughs. NASA has a renewed focus on lunar/planetary exploration that has resulted in science instruments being developed that are smaller, distributed, and eventually networked. If radioisotopes are to be avoided, existing capabilities will not meet future needs. Science instruments include magnetometers, seismometers, IR/mass spectrometers and several others. PALETTE is structured to meet the need by increasing thermal toolbox element TRL via four design/build/test tasks and four analysis/study tasks. Task 1 involves the development of nested thermally-switched enclosures featuring a new thermal switch that links a reverse-operation DTE thermal switch (ROD-TSW) to a propylene miniaturized loop heat pipe (mini-LHP). Task 2 involves the development of an affordable parabolic reflector radiator (PRR) for low-to-mid latitude lunar instruments. Task 3 involves the development of an ultra-low effective emissivity (e*) multilayer insulation (MLI) known as �spacerless� MLI. Task 4 involves the development of ultra-low conductance (G) thermal isolators. Prototype test results for Tasks 1-4 will be summarized in the paper as will the progress made on Tasks 5-8, the four analysis/study tasks. Task 5 focuses on optimizing gimbaled optical instruments, Task 6 on optimally combining thermal transport/storage/switching to achieve new instrument capabilities, Task 7 on instrument feed-through heat loss minimization, and Task 8 on instrument scalability, extensibility, and planetary use.