Spectrum Bidirectional Vis-NIR reflectance spectra of 99%-N2:1%-CH4:500ppm-CO tholins at various illumination-observation geometries (i=0°,30°,60° - e= -70° to 70°) Spectrum Single scattering albedo spectrum of 99%-N2:1%-CH4:500ppm-CO tholins derived from BRDF measurements Spectrum Optical constants spectrum of 99%-N2:1%-CH4:500ppm-CO tholins derived from single scattering albedo

Spectrum Bidirectional Vis-NIR reflectance spectrum of 95%-N2:5%-CH4 tholins (i=0°, e=30°)

Spectrum Bidirectional Vis-NIR reflectance spectra of 95%-N2:5%-CH4:500ppm-CO tholins (i=0°, e=30°) Spectrum Bidirectional Vis-NIR reflectance spectra of 95%-N2:5%-CH4:500ppm-CO tholins + 0.1% Pyrrhotite (i=0°, e=30°) Spectrum Bidirectional Vis-NIR reflectance spectra of 95%-N2:5%-CH4:500ppm-CO tholins + 0.2% Pyrrhotite (i=0°, e=30°) Spectrum Bidirectional Vis-NIR reflectance spectra of 95%-N2:5%-CH4:500ppm-CO tholins + 0.5% Pyrrhotite (i=0°, e=30°) Spectrum Bidirectional Vis-NIR reflectance spectra of 95%-N2:5%-CH4:500ppm-CO tholins + 0.67% Pyrrhotite (i=0°, e=30°) Spectrum Bidirectional Vis-NIR reflectance spectra of 95%-N2:5%-CH4:500ppm-CO tholins + 1% Pyrrhotite (i=0°, e=30°) Spectrum Bidirectional Vis-NIR reflectance spectra of 95%-N2:5%-CH4:500ppm-CO tholins + 2% Pyrrhotite (i=0°, e=30°) Spectrum Bidirectional Vis-NIR reflectance spectra of 95%-N2:5%-CH4:500ppm-CO tholins + 3% Pyrrhotite (i=0°, e=30°) Spectrum Bidirectional Vis-NIR reflectance spectra of 95%-N2:5%-CH4:500ppm-CO tholins + 5% Pyrrhotite (i=0°, e=30°) Spectrum Bidirectional Vis-NIR reflectance spectra of Pyrrhotite (i=0°, e=30°)