Solar cells are the critical power source for the majority of space missions. The advancement from single junction silicon cells to current, state-of-the-art, triple junction, germanium cells enabled greater mission power per weight, stowed volume and deployed area. Near-term, advanced solar cell technologies will range from 4 to 6 junctions, and include a variety of band gaps. Solar cell testing is critical to space missions. Every solar cell is tested at the cell level under continuous light and at the panel, wing and sometimes spacecraft level multiple times under LAPSS. Current test methods calibrate the light source by measuring the current output of each junction and adjusting the source accordingly. Today's sources are a combination of lamps and filters. As cells with more the 3 junctions come into test, more flexible sources of narrower bands will be needed and current methods will have extreme difficulty, complexity and expense trying to keep up with the variety of near-term advanced solar cell designs. We propose a solid state illumination source with enough discrete source wavelengths to be flexible enough to be calibrated to any number of junctions, up to 6, for continuous cell testing. In addition, this source would be cost effective enough to allow many sources connected together to perform large area testing, pulsed or continuous, for panel and wing level testing. Calibration would follow similar methods to the current practice, but would be simplified through a software interface.