Three spectrometers and associated experiments are described. The work reviewed comprises the early experimental phases of a program to develop a satellite infrared spectrometer capable of making radiometric measurements in the 15-micron carbon dioxide band needed for deduction of atmospheric temperature profiles. Initially, a simplified, breadboard spectrometer with four spectral channels was used to determine the temperature profile of the lower atmosphere from the ground. Next, a commercial spectrophotometer was modified and another determination of the atmospheric temperature profile was made using more spectral intervals. Instrument specifications for a balloon flight model spectrometer were derived from these experiments. Following the model*s fabrication, testing, and calibration, two high-altitude balloon flights were conducted to demonstrate that the atmospheric temperature profile could be ascertained from above the atmosphere.