ON-BOARD LIGHT SOURCE CALIBRATION

An example method includes recording dark images on an image sensor on-board an orbital vehicle during flight, which include a first image recorded before the orbital vehicle is over a predefined location on the Earth and a second image recorded after the orbital vehicle is over the predefined location; and recording third and fourth images on the image sensor during flight based on illumination from a light source that is on-board, with the third image being recorded before the orbital vehicle is over the predefined location and the fourth image being recorded after the orbital vehicle is over the predefined location. A fifth image is recorded on the image sensor during flight while the predefined location on the Earth is visible to the image sensor. The fifth image is based on light from a ground-based calibration system. The light source is calibrated during flight based on the five images.