Air Force Tracked Nuclear Blasts to Hide F-117 and F-22 Jets
By Miriam Adler ·
For decades, the military hid a pivot from monitoring the heat of the apocalypse to using an NKC-135E to strip away the privacy of the sky and mask stealth jets.
In 1961, the United States government began a project to measure the invisible. According to a program description mirrored by the Federation of American Scientists (FAS), the Flying Infrared Signature Technology Aircraft, or FISTA, did not begin its life as a tool for stealth. Instead, its first task was to examine the "infrared properties of the radiation from atmospheric nuclear blasts."
For over a decade, FISTA focused on the heat of the apocalypse—the radiation from nuclear explosions and the related "night sky and auroral phenomena." It is a clinical description for a period of history defined by fallout and the silent poisoning of the atmosphere. When the nuclear atmospheric test ban treaty finally brought an end to that specific requirement, the program did not dissolve. It simply pivoted.
Atmospheric Nuclear Blasts
By 1974, FISTA transitioned from measuring the aftermath of nuclear fire to mastering the art of invisibility. The mission shifted toward "measuring and understanding the infrared characteristics of aircraft" and how those aircraft could be detected and identified from platforms based in the atmosphere or in space. The objective was no longer to observe the blast, but to ensure that the instruments of American power could operate without being seen.
This data became the foundation for the Spectral and Inband Radiometric Imaging of Targets and Scenes, known as the SPIRITS database. The technical labor of this transition was distributed across several entities: the National Air Intelligence Center (NAIC), Air Combat Command (ACC), and the Air Force Information Warfare Center (AFIWC). Much of the current work is handled by the Stewart Radiance Laboratory at Utah State University for the Air Force Research Laboratory (AFRL).
There is a coldness to the way the record describes this evolution. The shift from the radiation of nuclear blasts to the "low-observable technologies" of stealth bombers is presented as a logical progression of "requirements." In reality, it represents a seamless transition in the state's pursuit of dominance—moving from the overt horror of atmospheric testing to the covert precision of the stealth era.
Document imagery from irp.fas.org From the files: irp.fas.org
The NKC-135E
For thirty-two years, the original FISTA aircraft served its purpose before being decommissioned in September 1993. The capability was then transferred to a new platform: the NKC-135E. This aircraft, FISTA II, completed its initial test flight on May 11, 1995.
FISTA II is less an airplane and more a flying laboratory designed to strip away the privacy of the sky. Its sensor suite consists of three imagers, three spectral sensors, and a dual-channel radiometer, providing coverage over "all infrared wavelengths of interest." To ensure the data is calibrated, the aircraft carries multiple video and film cameras to provide "background, aspect, and ranging information."
This level of sensory precision allows the Air Force to scrutinize its own fleet and its enemies with terrifying accuracy. The FISTA team at the Space Vehicles Directorate at Hanscom Air Force Base, Massachusetts, used this data to support the B-2 and F-117 programs. The goal is the total reduction of the aircraft's thermal footprint, ensuring that the machine can slip through the air without leaving a heat trail that a sensor might catch.
Predicting the Behavior of Paint
One of the most specific achievements of the program was the development of infrared computer models. These models allowed the Air Force to spend their time "characterizing and predicting the behavior of paint on signature characteristics of aircraft."
In the world of stealth, paint is not aesthetic; it is a strategic layer of deception. By modeling how different coatings interact with infrared sensors, the military can design aircraft with the "lowest-observable infrared signature." The record notes that FISTA II provides the means to test new design techniques and "low-observable coatings to assess their effectiveness."
This is the alchemy of modern warfare: using a specialized aircraft to ensure that other aircraft effectively do not exist to the eyes of the enemy. The F-22, among other platforms, relies on this "infrared specification compliance" to maintain its edge.
While the public record on stealth aircraft focuses on the shapes and angles that deflect radar, the FISTA documents highlight the invisible battle of heat. The program does not stop at aircraft; it also measures the "polarization properties of clouds" to help suppress "clutter" for scenes observed from space. The sky is treated as a series of obstacles to be filtered out, a background to be managed so that the target remains clear.
As of the last update to the FAS mirror on November 25, 1998, the program was continuing to expand. A new, calibrated visible imager had been developed, and new digital recording systems were being implemented to give the infrared imagers increased resolution and sensitivity.