Abstract: A device for verifying the calibration of an infrared sensor includes a body configured to be placed in orbit. The body defines a spin axis and an outer surface. The outer surface has an infrared radiant intensity that is substantially independent of the viewing angle between the spin axis of the body and the infrared sensor. The device may be used for on-orbit verification of the calibration coefficients associated with each pixel of an infrared sensor, including linearity calibration and verification of the resolution capability of the sensor. The calibration coefficients may be verified over the entire sensing capability range of the infrared sensor. After a thermal model of the device is developed, the device operates passively and provides a known source of infrared radiation observable during the device's entire orbital lifetime. The device may be designed to automatically de-orbit from space after a predictable time in orbit.