United States Air Force Infrared Sky Surveys

In the early decades of the Cold War, especially after the launch of Sputnik 1, the United States Air Force (USAF) became interested in methods for detecting and tracking ballistic missiles and satellites. These objects radiate primarily in the infrared, so it was natural to try to detect their infrared signatures. However the infrared appearance of a rocket being launched is very different than that of a satellite in orbit, so the Air Force wanted a suite of infrared detectors that would cover much of the infrared part of the spectrum. Additionally, the Air Force needed to know what permanent background sources were in the sky, to allow discrimination of target from background. Astronomical sources could also be used for detector calibration. Astronomers had not yet mapped the infrared sky, and much of the infrared radiation could not pass through the atmosphere and be observed from the ground. The Air Force began a program that ran from the mid-1960s, through the 1970s and into the 1980s to map the sky at several different infrared wavelengths. The US Department of Defense called this mapping program Infrared Celestial Backgrounds. This program produced the AFCRL, AFGL and RAFGL catalogs.

Although the USAF mapping efforts overlapped in time with the data collection for the Two-Micron Sky Survey (IRC), the IRC catalog was published six years before the first USAF results were officially made public. However the IRC survey was a ground-based effort at a single near-infrared band, and the USAF surveys were sub-orbital space-based multi-band surveys covering the mid and far-infrared.