NOSS Satellite Intelligence System: Secrets of Cold War Espionage

General view of the Parcae satellite of the first series. NRO graphics
In the mid-seventies, the United States began operating the latest satellite system of electronic intelligence, NOSS. It included the Parcae series of spacecraft and many different ground systems and complexes. With the help of all these products, the Pentagon tried to monitor the World Ocean and search for Soviet Navy ships. fleet.
Search tasks
The sixties and seventies of the last century were a period of active development of the USSR Navy. Numerous ships and submarines of various types were built, and new directions were mastered. Every year the potential of the fleet grew, and the areas of its presence also increased. The development of the Soviet Navy predictably worried the potential enemy in the person of the USA and other NATO countries.
In the early 1970s, the Pentagon decided it needed a new intelligence system capable of monitoring the oceans, finding Soviet squadrons, and transmitting data to its own navy. These tasks were to be accomplished using advanced space technology.
By that time, the Pentagon had managed to develop and put into operation its first electronic reconnaissance satellites (IRS). It was the existing Poppy series devices that were used in ship-search experiments. They demonstrated the fundamental possibility of detecting such objects in the ocean, but processing the collected data took an unacceptably long time.
Based on the results of the tests, a decision was made to develop a new specialized reconnaissance system that would have all the necessary capabilities and the required level of performance. The National Reconnaissance Office (NRO) developed a technical assignment, and work began on the new project.

Payload stage with three satellites. Photo Spectrum.ieee.org
The project was named NOSS (Naval Ocean Surveillance System). The prospective satellite for this system was first named White Cloud, and then Parcae (the three goddesses of fate in Roman mythology).
The project was commissioned by the NRO, and the Naval Research Laboratory (NLR) was the lead contractor. In addition, several commercial contractors were involved in the project, who were supposed to supply various products and components.
Due to its special role and importance, the NOSS system was created and operated with strict secrecy. As a result, official information about the Parcae satellites first appeared only a few years ago. Before that, only fragmentary and unconfirmed data, as well as various estimates, appeared in the specialized press.
Two echelons
The goal of the NOSS project was to create a ground-space system capable of monitoring large areas of the ocean and searching for potential enemy ships. It would then transmit targeting data to various forces and assets. To achieve maximum performance and optimize costs, it was decided to use a proven architecture.
The key part of the system was proposed to be satellites with special equipment. In addition, a whole network of stations with receiving and transmitting equipment and data processing facilities was to be deployed on the ground. Both components of NOSS were planned to be developed from scratch, although using ready-made solutions and available components.

The SEL-180 computer used in the NOSS ground assets. Photo: Spectrum.ieee.org
The general appearance of the Parcae series satellite is known. It had a rectangular body, no more than 1-1,5 m long and wide. Folding solar panels were located at the corners of the body. In addition, similar elements covered the curved back cover of the device. In the middle of the cover there was a telescopic rod with a load - the so-called gravity boom, with the help of which the device was constantly oriented towards the Earth. The second cover of the body carried a set of receiving antennas and was directed to the search area.
On board the Parka was a multi-band radio station with directional antennas. It was supposed to collect and record all radio signals from the required area of the globe. A separate station for two-way communication with the ground was also envisaged.
A special payload stage was developed for the new series of satellites. It could accommodate three devices, as the "ancient Roman" name of the project hinted at. The stage met the requirements missiles- carriers of the Atlas family.
Within the framework of NOSS, it was planned to build a large number of ground stations that would combine radio and computer components. They would use the most modern computing equipment of that period, such as the SEL-810 or SEL-86 computers. They were supposed to ensure the speed of the entire system.
During operation, the NOSS system and its components were repeatedly modernized. Open sources mention three generations of spacecraft. Ground-based assets apparently developed continuously and consistently, without a clear division into series and generations.
The system in action
The operating principle of NOSS in its original form was quite simple. Using the Atlas, one of the serial modifications, a payload stage with three satellites was launched into orbit. Then, Parcae was sent into near-earth orbit at an altitude of 1000-1200 km. The devices were dropped one by one at specified points in space at a distance from each other.

The Poppy reconnaissance satellite is the de facto predecessor to Parcae. Photo by the US Department of Defense
The satellites were oriented toward the Earth using a "gravity arrow" and began their work. Their task was to search for and receive any signals that could come from potential enemy ships. All received signals were recorded in the internal memory until the next communication session.
During the flight, the devices were supposed to pass near the NOSS ground stations and transmit the collected data to them. Then, using computers, the received data was analyzed. A special program looked for similar signals and then calculated the location of their source using triangulation.
Depending on various factors, the calculations took no more than a few minutes. The computer could produce coordinates of the supposed location of the signal-source ships or a map with the necessary markings. This information was then transmitted via existing communication channels to the Navy headquarters, ships and submarines, etc.
Secret launches
According to known data, the first three Parcae satellites were launched into orbit on April 30, 1976, using an Atlas E/F rocket. These devices operated in space for more than a year, after which they needed to be replaced. Between December 1977 and May 1987, eight more launches took place as part of the so-called first series. The fourth launch, which took place in December 1980, ended in an accident and the loss of the satellites.
The second series included only four rockets with payload stages and 12 satellites. These devices were launched into orbit from 1990 to 1996. The lower intensity of launches and work in general was due to the reduction of the payload. During this period, the former Soviet Navy was going through hard times and did not require the same level of attention. It is assumed that the satellites of the second series were significantly different from the earlier Parcae.

Launch of an Atlas E/F rocket. The same rockets were used to launch the Parcae satellites. Photo by NASA
According to available data, the NOSS system continues to function, and NRO actively supports it. The last launch, during which two devices were launched into orbit, took place not so long ago, in 2022. From open sources it follows that now not "Parks" are used, but satellites of a completely new model. However, detailed information about modern satellites is still missing.
Results and consequences
The first version of the NOSS system was in operation for over 20 years. Thanks to it, American intelligence was able to monitor different areas of the World Ocean and search for Soviet ships. The chosen method of reconnaissance generally proved itself, due to which the system was repeatedly modernized and is still in service.
It was noted that the NOSS system and its components have several important advantages. First of all, it was the relative simplicity of operation. During the reconnaissance process, only three satellites were simultaneously used, which were launched into orbit simultaneously. With a certain complexity of the devices themselves, good savings on rockets and other expenses were achieved.
The ground components of the system received high marks. Their development was quite complex, but it was they who allowed to increase the speed of calculations and reduce the time before the target coordinates were issued. In addition, they once again confirmed the high potential of computers in the military sphere.
The NOSS system had significant potential for modernization, which allowed it to solve the tasks set and remain in operation for a long time. Moreover, after another update and replacement of components, the system continues to function to this day.
Thus, in the seventies, American intelligence and industry were able to solve an important problem - to establish surveillance of the fleet of a strategic rival. In addition, they laid the foundation for further developments in the field of space intelligence and still use it to one degree or another.
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