In-flight Evaluations of Tungsten Calibration Lamps Using Shortwave Thermistor Bolometers and Active-cavity Radiometers

The stabilities of type 715, T-1, tungsten calibration lamps were evaluated aboard three spacecraft platforms during the period 1984 to 1989. In the 0,2 μm to <5,0 μm broadband spectral region, the emitted radiant power from each lamp was measured using shortwave thermistor bolometers and active-cavity radiometers. The radiant power was found to be constant to ±1%. The responses of filter and silicon photodiode monitoring systems used to evaluate the lamps were found to degrade as much as 6% during the first two years in orbit.