||ESA's Project for On-Board Autonomy satellite, better known as PROBA, is one of the most advanced small satellites ever flown in space. Since its launch in 2001 PROBA's novel computer system and technologically advanced instruments have enabled it to demonstrate and evaluate onboard operational autonomy, new spacecraft technology both hardware and software, and to test Earth observation and space environment instruments in space. The instrument payload includes a Compact High Resolution Imaging Spectrometer (CHRIS), a radiation measurement sensor (SREM), a debris measurement sensor (DEBIE), high resolution and wide angle Earth pointing cameras, a star tracker and gyroscopes. The objective for CHRIS is to provide Earth surface reflectance data in the visible/near infrared, at high spatial and spectral resolution, for scientific studies. The instrument uses the PROBA pointing capabilities to obtain reflectance measurements with a wide range of different viewing configurations, and provide Bi-directional Reflectance Distribution Function (BRDF) data for selected test sites on the Earth's surface.