Pandora is a SmallSat-recently selected for further development for NASA’s inaugural Astrophysics Pioneers program-designed to characterize exoplanets and their host stars with long-duration, multiwavelength observations. The primary objectives are to quantify and correct for stellar contamination in exoplanet transmission spectra, and robustly identify atmospheric features, for 20 stars (with 39 planets). Pandora will monitor each star using an optical photometric detector (300-600 nm), which provides high contrast for measuring changes in brightness. An IR detector (900-1750 nm), operating simultaneously, will capture changes in spectral features that correlate with stellar photometric variability. The strength of Pandora’s combined time-series photometry+spectra is that it will provide constraints on the absolute spot coverage of stars, and provide the necessary spectral information to allow us to decompose the stellar spectrum into its constituent parts (spot, faculae, and quiescent photosphere) and measure physical quantities (spot and faculae contrasts and covering fractions) at the time of a planet transit. This unique data will enable us to disentangle star and planet signals in transmission spectra. Pandora will observe a wide range of star types (mid-K to late-M) and planet sizes (Earth- to Jupiter-size) - observing 24 hours around each transit, with 10 transits per planet-a baseline long enough to identify correlations between stellar contamination levels and planet/star parameters. Pandora will have sensitivity to identify exoplanets with hydrogen- or water-dominated atmospheres, and can determine which planets are covered by clouds and hazes. Pandora will operate concurrently with JWST, and can inform target selection for more in-depth atmospheric studies by JWST and future missions.