Home >> January 2009 Edition >> COMM OPS: EW, ELINT, + SURVEILLANCE SATS
by Jos Heyman, Tiros Space Information

In this presentation, we will look at military early warning satellites, electronic intelligence gathering satellites, and ocean surveillance satellites launched by the United State military forces. Information about these satellites is invariably secret and the satellites are not given a name at the time of launch, or, in recent years, are grouped in a series of diverse military satellites simply identified as USA, without any further indication as to the objective.

Historians/analysts can often determine the objective of a satellite from the small bits of information that are available, including the launch site and the launch vehicle, but some of the information only arrives years after the launch. It is for this reason that the interpretation of this information by individual historians/analysts may sometimes result in different identifications. Until the programs concerned are declassified, these differences will occur.

Early warning satellites provide an advance warning of missile attacks through the detection of missile exhaust plumes. Electronic intelligence (elint) satellites pick up and record radio transmissions and radar transmissions while over foreign territory and then play back this information once over friendly territory. The information gained in this manner gives an insight into the strategy of the opposing powers and also reveals the location of the radar sites. Ocean surveillance satellites locate and monitor the movements of naval vessels by means of electronic equipment.

Early Warning Satellites

Midas series
The primary objective of the early warning satellite development was to fill the gaps in the coverage provided by the land based Ballistic Missile Early Warning System used by the United States to provide an early detection of a missile attack. This system initially consisted of a chain of large radar stations, which observed the USSR.

The Missile Detection and Surveillance (Midas) series of satellites was initiated in 1960 and appeared in two generations. The initial Midas spacecraft, which had a mass of about 2000 kg, were launched by Atlas Agena A launch vehicles. The combination of the mass and the limited capabilities of the launch vehicle allowed the spacecraft to achieve only a low near-equatorial orbit of about 540 km altitude. The introduction of the Atlas Agena B version and the reduction of the mass of the spacecraft to 1600 kg through the use of solar cells allowed a higher orbit of 3500 km, commencing with Midas-3.

The satellites were equipped with infrared sensors developed by IT&T, which could detect missiles as soon as they would be launched. It is believed the program was only partially successful due to the limited capability of the sensors that were carried.

The sensor development undertaken as part of the Midas program led briefly to a satellite proposal identified as Code 461. This program was cancelled in favor of the Code 266 program, which the author has labeled as Improved Midas. The three satellites in this series are believed to have tested the use of television cameras in conjunction with the infrared detectors, but may not have been successful. BMEWS
The BMEWS series of satellites is the prime example where historians/analysts, at the time of the launch, deduced an objective from the little bit of information that was available and which, with the passing of time, proved to be incorrect.

The Ballistic Missile Early Warning System (BMEWS) satellites were to have followed in the footsteps of the Midas series as an experimental early warning system. Also referred to as Program 949, the satellites were believed to have been built by TRW and were to have been equipped with infrared sensors developed by Aerojet and a television system developed by RCA.

Six satellites were earmarked as such and the first satellite in the series was placed in a near-geostationary orbit with an inclination of 10°, giving it a figure 8 orbit with an apogee over the USSR. This type of orbit gave the satellite an extended time over the western part of the USSR. The second satellite in the series was placed in a geostationary orbit, while the third failed to achieve a correct orbit. Following the failure of fourth satellite, the fifth achieves the desired geostationary orbit. The final satellite was believed to have been an experimental flight. Subsequent information has led to the revision of the objectives of the satellites concerned, as shown in the table. Ironically, none of the satellites were associated with early warning efforts.

IMEWS series
The Integrated Missile Early Warning System (IMEWS) satellites were the first early warning satellites of an operational nature. Also referred to as Code 647, Program 266, AFP-949, Defence Satellite Program (DSP) and LS-3A, the system was inaugurated in 1970 and three operational satellites were placed in geostationary orbits over the Atlantic, Indian, and Pacific Oceans to provide a global surveillance capability. In addition, the system had two satellites as in-orbit spares. The satellites, built by TRW, were equipped with television cameras and infrared sensors operating through a Schmidt telescope, which was offset from the main axis of the satellite by 7.5° so that, with the satellite spinning at 6 rpm, a conical scanning pattern was achieved. Over several scans, this allowed observers to distinguish between a stationary heat source (for instance, a forest fire) and a moving heat source (a missile). In addition, the satellites were equipped with thrusters for station keeping and at the end of their operational life they were boosted into a higher orbit.< br />
The first generation consisted of IMEWS-1 to -4 and it is believed the satellites carried an array of 2000 infrared sensors. The satellites reportedly had a length of 7 m and a diameter of 2.78 m with a mass of 1100 kg.

The second generation commenced with IMEWS-5 and incorporated several improvements as well as some additional instrument packages, although the main sensor payload remained essentially the same.

Commencing with IMEWS-8 the Multi-Orbit Satellite/Performance Improvement Modification (MOS/PIM) was introduced, which allowed multiple targets to be accessed. The extra electronic packages increased the mass to 1170 kg.

IMEWS-12 introduced an improved resolution as well as better polar/global coverage. The main sensor payload, known as Sensor Evolutionary Development, had increased to 6000 detectors while an Above the Horizon (ATH) capability provided improved polar coverage. The mass of the satellites had increased to 1674 kg.

The third generation, commencing with IMEWS-14, was equipped with an improved telescope and 6000 infrared sensors. The satellites in this generation had a length of 10 m, a diameter of 4.15 m, and a mass of 2500 kg. Some, or all, of the satellites in the series also carried a magnetospheric plasma analyser to measure low&#8209;energy ions and plasma, as well as a particle analyser, to measure energetic particles. Following the launch of IMEWS-23, the remaining two satellites, IMEWS&#8209;24 and &#8209;25, were cancelled. BSTS
In the mid-1990’s, the United States hoped to establish the Boost Surveillance Tracking System (BSTS) series to monitor the launching of enemy missiles as well as cue the weapons deployed against such a threat. These satellites, to be designated by the U.S. Air Force as LS-6A, were to be equipped with a large telescope with a wide field of view infrared mosaic sensor as well as a narrow field of view camera and some secondary instruments. Unlike the IMEWS series of satellites, which operated from geostationary orbits, the BSTS series would also have covered the Polar Regions. Rockwell and Grumman undertook initial studies, but the changing political climate as well as the escalating costs caused the cancellation of this series of satellites.

In the early 1990s, proposals to replace the IMEWS system were investigated as the Alert Locate and Report Missile (ALARM) satellite system and the Follow-on Early Warning System. Both systems were abandoned due to insufficient technological capabilities to meet the requirements as well as too high cost. By 1996, these proposals evolved into the Space Based Infrared Systems (SBIRS), which initially envisaged…
  • Four SBIRS High GEO satellites which were to be placed in a geosynchronous Earth orbit
  • Two SBIRS High HEO satellites which were to be placed in a highly eccentric Earth orbit
  • 24 to 30 SBIRS Low satellites which were to carry radar to track hostile ballistic missiles and discriminate between the warheads and other objects, such as decoys, that would separate from the missile bodies throughout the middle portion of their flights

The first of four SBIRS High GEO satellites is scheduled for launch in 2009, with the second one scheduled for 2010. No launch date has been set for the third satellites and it is quite likely the fourth has been cancelled. The satellites, developed by Lockheed Martin and Northrop Grumman (originally TRW) will carry sensors that will cover short-wave infrared, expanded mid-wave infrared, and see-to-the-ground bands allowing it to perform a broader set of missions as compared to IMEWS.

The two SBIRS High HEO satellites turned out to be payloads on other satellites with SBIRS HEO-1 launched on June 28, 2006, as a payload on the Prowler-1 elint satellite and SBIRS HEO-2 as a payload on the Prowler-2 satellite that was launched on March 13, 2008.

The SBIRS Low satellites were scheduled to be launched in 2010, but the program, undertaken by TRW, was cancelled around 2001. By then, TRW had built two SBIRS-Low Flight Demonstration System (FDS) satellites to test some of the hardware. These satellites were scheduled to be launched in late 1999 aboard a single Delta 7420-10C launch vehicle.

The cancellation of SBIRS Low did not do away with the military need for a constellation of low-Earth orbit tracking satellites. A new program called Space Tracking and Surveillance System (STSS) (designated as LS-9A by the U.S. Air Force) replaced SBIRS Low. The two SBIRS Low FDS satellites are being reused as the basis for the STSS Cycle 1 mission, which are to be launched by Delta 7920 launch vehicles from Cape Canaveral in April 2009 and which will test technology for operational SSTS satellites.

Elint satellites

The United States has launched several types of elint satellites. The first series is commonly referred to as Ferret, but no formal names are known. Several sub-series appear to have been built. Lockheed built one series, while a second series was built by Hughes as Program 711. They may have been cylindrical in shape with a length of 8 m, a diameter of 1.5 m and a mass of 2250 kg. Another series, of which 15 were launched, has been identified as Saint, Samos F-2, Samos F-3, Program 102, Program 698, Program 706, Program 770, and Program 704. They had a mass of 1500 kg, a length of 11.75 m and a diameter of 1.5 m. They usually operated in 500 km orbits.

Other Ferret satellites have been launched as ancillary payloads to various military satellites. These have been referred to as Pickaback and Hitchiker, but there is evidence that the use of these satellites also extends to small scientific and technology payloads.

The U.S. Navy had its own series of elint satellites, which was not revealed until 2005. The Poppy series of satellites were developed and built by the Naval Research Laboratory to collect radar emissions of Soviet naval vessels. The program involved seven launches, some of them multiple satellites. However, apart from the launch dates, the statements associated with the de-classification of the information did not give details of the instruments. Also, as some Poppy satellites had been part of multiple satellite launches, there were no details as to which satellites were the Poppy satellites. It is, however, thought that the Poppy satellites were those previously identified as Ferret-3, Calsphere-1, Radose, Solrad-5B, Solrad-6B or Ferret-12, GGSE-4, Ferret-24 as well as a number of satellites that never previously received a name.

The extent to which the objectives of these satellites were suppressed is expressed in the use of the Solrad series for at least two of them. The Solrad series of scientific satellites were sponsored by the U.S. Navy. They were used to investigate solar X&#8209;rays and particle emissions which result in disturbances in the ionosphere and the assessment of the effects of those disturbances on satellite and ground based communications. The series was also referred to as Galactic Radiation Experiment Background (GREB).

Canyon, Chalet and Vortex
The Canyon series of satellites were signals intelligence gathering satellites placed in so-called quasistationary orbits. These differ from a geostationary orbit in that they have an inclination of 3° to 10° with altitudes between 30,000 km and 42,000 km. With these parameters, the satellite does not remain stationary relative to the Earth, but moves in a complex elliptical trajectory, thereby providing a broad view in the course of a day. This orbit also allows the direction to radio emitters to be measured from various points of the orbit which allows the determination of the location of the emitters through triangulation.

The satellites were part of the National Reconnaissance Office’s Program A. The highly classified satellites were developed by the U.S. Air Force and were also known as Program 827 or AFP-827. It is believed the satellites were 1.5 m in diameter and were fitted with one or more 3 m diameter antennas or a single 10 m antenna.

Successor programs to Canyon were known as Chalet and Vortex, although these might be merely new cover names for upgrades to the same system. The Chalet series of satellite, which were also known as Program 366 or AFP-366, are believed to have been with a large parabolic antennas of up to 45 m diameter, or even more, giving the spacecraft a mass of app. 1400 kg.< br />
The Vortex satellites are believed to have been fitted a deployable antenna with a diameter of 80 m and have a mass of approximately 5000 kg. The Vortex series of satellites is also known as Mercury.

Rhyolite, Magnum, Orion
The RH or Rhyolite series of satellites were placed in geostationary orbits for the interception of telemetry signals of missile test launches. The program has also been referred to as Program 720 or AFP-720. Built by TRW, the 278 kg satellites were launched in a size of that of half a freight container. In orbit, the satellites unfolded into a 29 m diameter antenna with a framework grid to which large solar panels were attached. The operational system is believed to have consisted of two satellites monitoring the USSR and China. When the Rhyolite name became public, the system was renamed as Aquacade.

The successors to the Rhyolite series were named Magnum. The satellites had a length of 10.84 m, a diameter of 3.55 m and a mass of 3600 kg and were fitted with large diameter antennas. The next generation was known as Orion, while the name Mentor has also been mentioned.

Jumpseat, Advanced Jumpseat, Trumpet, Prowler
The Jumpseat series of military electronic intelligence gathering satellites were placed in highly elliptical orbits to monitor transmissions to and from USSR/Russian Molniya communications satellites.

The satellites are believed to have been built by Hughes and may also have been known as AFP-711, Code 711 or Code 980. Because of their orbit, the Jumpseat satellites are sometimes referred to as SDS military communications satellites.

The second generation of these satellites was known as Advanced Jumpseat. This generation have carried anti&#8209;satellite alarm and avoidance systems as well as a manoeuvring capability.

The third generation of these satellites has been identified as Trumpet and Prowler. It is believed these satellites had an antenna with a diameter of 90 m. As mentioned earlier, the Prowler satellites also had an early warning capability.

Ocean Surveillance

As naval vessels operate under radio silence and maneuver to maintain positions under cloud cover whenever possible, an obvious application for space technology was an ocean surveillance system using radar to penetrate the clouds and locate the naval vessels. The United States Navy initially used data generated by reconnaissance satellites but then embarked on the study of a dedicated ocean surveillance satellite under the designation of Code 749. Although no satellites were ever realized in this program, it eventually gave rise to the NOSS series.

The satellites in the Naval Ocean Surveillance System (NOSS), which are also referred to as Whitecloud, were placed in orbits of 1600 km altitude with an inclination of 63° and a separation of 100°. It is believed the satellites carried side and forward looking radar, multi-spectral scanners and infra-red detectors and are said to have had the capability to detect warm water in the wake of a submerged nuclear submarine. To date, three separate generations have been identified, but the NOSS program remains highly classified.

The NOSS satellites were accompanied by sub-satellites, which are believed to have transmitted data to the main satellite. Cables to the main satellite connected some of these sub-satellites. They have been referred to as SS, SSU, GB, EP, or JD, although the meaning of such designations is not known.

Since 1986, they have been included in the USA series of satellites. With the introduction of the third generation of NOSS satellites, only one sub-satellite was launched, although official records do not catalogue these satellites. Instead, the objects visual observers believe to be the sub-satellites have been catalogued as debris. Vela
In a class of its own, the Vela series of highly sophisticated satellites were launched in pairs between 1963 and 1970 to detect nuclear detonations in the Earth’s atmosphere.

Being part of an overall system consisting of Vela Uniform, to detect underground detonations, and Vela Sierra, to detect surface detonations (neither of which used satellite technology), the system is also known as Vela Hotel.

The satellites, which were built by TRW, were equipped with detectors to identify X-rays, gamma rays, and neutron emissions which were not only used to detect nuclear detonations, but were also effectively used to gather scientific data on solar flares and other solar radiation. The satellites were placed in orbits of 112,000 km altitude with an inclination of 35°. Pairs were separated by 180‚.

The first six satellites had a mass of 231 kg and carried 18 detectors. Vela-5 and -6 also carried additional ultra-violet and visible light sensors. The next six satellites carried also optical and electro-magnetic pulse detectors and had a mass of 236 kg. Nuclear detection equipment was later incorporated in other satellites such as Magnum and the Navstar navigational satellites.

About the author
Jos Heyman is the Managing Director of Tiros Space Information, a Western Australian consultancy specializing in the dissemination of information on the scientific exploration and commercial application of space for use by educational as well as commercial organisations. An accountant by profession, Jos is the editor of the TSI News Bulletin and is also a regular contributor to the British Interplanetary Society’s Spaceflight journal.