To hide its satellites in space from bad actors, Space Force needs to make them smaller. This goal is characterized as target signature reduction. The solar panel is the largest component on the spacecraft that could be reduced. To reduce the size of the solar panels and get the same power, new higher-efficiency solar cells need to be developed. To get to higher efficiencies, more p-n junctions need to be added to solar cells. The Air Force Research Laboratory is developing these higher-efficiency cells with more junctions through the Roset program, but the solar industry lacks ground test equipment to measure the advanced cells with precision and accuracy. Angstrom Designs has developed a test system, called the Programmable Light Emitting Diode Solar Simulator, or pLEDss, to measure all current solar cells up to five-junctions. Angstrom Designs has also just completed a AFRL SBIR Phase I to develop a 6-junction measurement for testing newly developed six-junction cells. If selected, this project would advance the development of pLEDss test equipment that could provide ground truth for six-junction space solar cells, potentially enabling target signature reduction for Space Force. The technical approach is to build on the existing 5-junction pLEDss system by executing a series of tasks. Task 1 will analyze, design, manufacture and test the successful 6-junction light source research from the AFRL Phase 1 SBIR development to produce prototype 6J pLEDss LED modules. Testing of these modules will validate the design capabilities. Task 2 will streamline manufacturing processes so the 6J capable pLEDss systems can be manufactured at reasonable cost and timing for the Space Force industrial base. Task 3 will expand Angstrom Designs existing measurement and analysis software tools to incorporate 6J functionality. Task 4 will build and test one (1) 0.5m x 0.5m 6-junction pLEDss test system that will enable solar panel measurements of all currently available space solar cell technologies, including 6-junction cells. This proposal seeks to develop technology that the US Space Force and its prime contractors can leverage to develop state of the art space solar cell technology and further the US Space Forces goal of target signature reduction.