"Fastwalkers," a term coined by the North American Aerospace Defense Command (NORAD) to classify unidentified flying objects detected by space sensors, has been the subject of much speculation and misinformation. The Fastwalker story began during the early days of the Cold War, when the U.S. placed a series of spy satellites in geosynchronous orbit to detect the launch of Soviet ballistic missiles and track their reentry vehicles.
Frequently, the space-based early warning system - which had an unimpeded field of view from orbit - would observe reflected flashes of sunlight from unknown objects passing through the sensor net moving much too fast to be enemy projectiles, but not fast enough to be cataloged as natural bodies such as meteors or even man-made space debris.
Not bound by conventional orbital mechanics, fastwalkers presented NORAD with an additional level of complexity in their task of protecting North America form a sudden nuclear strike, a situation that vexed the space surveillance agency for decades to come. In order to mitigate the constant misidentifications between fastwalkers and thrusting bodies such as intercontinental ballistic missiles, several algorithms were developed and deployed by the Air Force, which successfully curtailed the stream of false positives originating from orbiting intelligence platforms.
In the video below, a story is presented of an incident that was pivotal in the innovation of military space technology capable of tracking and cataloging fastwalkers. Although much of the event remains classified and not subject to Freedom of Information (FOIA) requests, enough is known to establish a clear picture of the severity of the problem NORAD faced in the early day due these swift extraterrestrial objects.