Calibration for astrophysics using an artificial star with NIST-traceable distribution of luminous energy (CANDLE) instrument development

The CANDLE Engineering Demonstration Unit (EDU) was selected by the 2022 APRA program to develop and demonstrate the ability to reach the flux accuracy and range required for an artificial flux calibration star. A critical issue in producing accurate and reliable flux calibration is systematic effects; this EDU is providing a path to deploying an artificial star calibration payload outside Earth's atmosphere with SI-traceable calibration that enables accurate throughput characterization of astronomical and earth science observatories in space and on the ground. Such a payload could be carried independently on a dedicated platform such as an orbiting satellite, e.g. the Orbiting Configurable Artificial Star (ORCAS), by a star shade at L2, or some other independent platform to enable accurate end-to-end throughput vs. wavelength calibration that can be measured repeatedly throughout the operational lifetime of an observatory. Once calibrated, the observatory is enabled to carry out astrophysical programs whose science objectives demand high accuracy and/or high precision observations. One specific and immediate application is establishing SI-traceable standard stars beyond the current limited set. We show in this paper the progress made in developing this EDU.