Lockheed P-11
(Program 989)

The early reconnaissance satellites of the CORONA program often carried secondary payloads for SIGINT (Signal Intelligence) purposes. These were usually mounted on the aft payload rack of the Agena spacecraft, and were therefore known as AFTRACK missions. From 1962 onwards, the AFTRACK program was managed by the newly formed National Reconnaissance Office. Mounting the payloads on the Agena limited their operational lifetime to that of the host vehicle, which was not more than a few weeks for a photo-reconnaissance satellite. In early 1963, the NRO therefore began a program to host the payloads on separate small satellites. These were still carried to low-earth orbit by the Agena module of photo-reconnaissance missions, but then separated and moved into their own orbits. The basic satellite vehicle (the "bus") was built by Lockheed, and known as P-11 (a Lockheed project number, not an NRO one). The P-11 was of retangular shape, with dimensions of approximately 1.5 m × 1 m × 0.5 m. It was equipped with small solid rocket motors to boost it into a slightly higher orbit after separation from the host. For early systems, a typical weight including the payload was around 110-140 kg (250-300 lb). The unclassified numerical designation of the SIGINT sub-satellite program was initially Program 770C, but was changed to Program 989 before the first mission. The payloads carried NRO Mission numbers in the 7300 series.

The first P-11 satellite was to be launched into space on 18 March 1963 with a CORONA KH-4 satellite, but the launch vehicle failed. The second attempt on 27 June, again on a KH-4 mission, was successful. The first two P-11 satellites, as well as another one launched in August 1964, carried scientific payloads, and were publicly known as Hitchhiker (for obvious reasons). The first launch of NRO's Program 989 / Mission 7300 occurred on 29 October 1963, when the PUNDIT 1 payload was placed in orbit.

Until 1992, a total of 49 Program 989 payloads were launched into space on P-11 satellites. Most were tasked with gathering ELINT (Electronic Intelligence) on Soviet air-defense and anti-ballistic missile radars, including general search, technical intelligence, direction finding and EOB (Electronic Order of Battle) intelligence. The satellites operated in low-earth orbits, and featured antenna systems sensitive enough to detect the side-lobes of Soviet radar systems. The received signals were typically recorded on tape, and transmitted to earth when a ground station was within line-of-sight. Most systems could also act as a transponder, relaying signals directly to a ground station, when one was reachable while intelligence signals were tracked. The following table gives an overview on Mission 7300 payload tasks:

^* PUNDIT 3 didn't reach orbit due to a booster failure. The LEIGE/PLICAT satellite suffered an in-orbit electric failure before the actual mission had begun. FARRAH 4 didn't activate after it had reached orbit.
^† The FARRAH 3 to 5 missions used a significantly revised satellite design, and are still classified.

Abbreviations:

• EOB = Electronic Order of Battle
• DS = Direction Finding (geolocation)
• GS = General Search
• P&CW = Pulsed and Continuous Wave
• TI = Technical Intelligence

PUNDIT, SAVANT (Telemetry Copy)

The PUNDIT satellites, among the first ones of Program 989, were built to copy the telemetry signal of Soviet missile tests. That mission was also assigned to the later SAVANT payloads.

Photos: NRO, via Dwayne A. Day
P-11 4001 (PUNDIT 1)		P-11 4401 (PUNDIT 4)

FANION

The FANION payloads were the first ones to provide a single spacecraft geolocation capability. They were designed to find the locations of a certain type of Soviet radar, but exactly which type that was is still classified.

Image: NRO, via Dwayne A. Day

P-11 4402 (FANION 1 / TRIPOS 1)

MAGNUM, SLEWTO

The one-of-a-kind MAGNUM and SLEWTO satellites pioneered TI (Technical Intelligence) of Soviet "Hen House" ABM (Anti-Ballistic Missile) radar systems. They were succeeded by the TIVOLI series.

LAMPAN, SAMPAN, TRIPOS, SOUSEA, VAMPAN, TIVOLI (ABM Radar ELINT)

These systems were all designed to detect and geolocate Soviet ABM radars, which was a very prominent part of the various ELINT tasks of Program 989. LAMPAN, SAMPAN, TRIPOS and SOUSEA covered L-, S-, C- and X-bands, respectively, while VAMPAN covered the lower frequency VHF spectrum. The TIVOLI satellites provided techincal intelligence on the ABM systems.

Image: NRO, via Dwayne A. Day

P-11 4411 (LAMPAN 1 / SAMPAN 2)

Image: NRO, via Dwayne A. Day

P-11 4421 (TRIPOS 4 / SOUSEA 3)

MABELI

MABELI (Mainbeam TIVOLI) was another TI payload, basically a more advanced successor to TIVOLI. It provided detailed mainbeam TI for several types of Soviet ABM radars. The MABELI satellite had an exceptionally long lifetime of more than 7 years, and was actually functional until it reentered the atmosphere.

Image: NRO, via Dwayne A. Day

P-11 4424 (MABELI)

WESTON, TOPHAT, ARROYO (COMINT)

A few satellites of Mission 7300 were not built for radar ELINT, but for COMINT (Communication Intelligence) purposes. The first of these was WESTON, designed to intercept and record two specific Soviet communication systems, known in NATO by the reporting names "Mercury Grass" and "Dawn Rose". WESTON wasn't entirely successful, though. Its launch was delayed for several years, and once in orbit, it ceased to operate relatively soon (accounts vary between 1 and 11 months) when its power supply failed.

TOPHAT covered a still classified COMINT mapping requirement, i.e., it recorded communication links and geolocated the sources. ARROYO was a one-of-a-kind COMINT system, which was designed to locate a very specific point-to-point communication system. The ARROYO satellite became inoperative after only 1 month into the mission, when its power supply failed.

Image: NRO, via Dwayne A. Day

P-11 4423 (TOPHAT 1)

URSALA, RAQUEL

In the air war over Vietnam, many American aircraft were lost to Soviet-built surface-to-air missile systems. By 1970, no ELINT information about these systems' radars was available. Existing Mission 7300 satellites couldn't detect Ku-band (12-18 GHz) emitters, and could also not handle "double-agile" radars which simultaneously change radar frequency and pulse timing between pulses - two features strongly suspected to be used by the SAM radars. The address this issue, two new types of P-11 based satellites were devised: URSALA (Universal Radar Search And Location Acquisition) and RAQUEL (Radar AcQUisition Equipment with Location).

URSALA detected double-agile radars in the 2-12 GHz frequency range. Four URSALA satellites were launched between July 1972 and March 1979. The first two had an in-orbit weight of 178 kg (393 lb), while the later two were significantly heavier, at 259 kg (570 lb). Even though the requirement for URSULA originated from tactical needs, the data was initially processed and analyzed at a national level, e.g. by the NSA. Later, in the mid-1970s, the TENCAP (Tactical Exploitation of National CAPabilities) program was begun. One of the first implementations of TENCAP was making ELINT information from Program 989 satellites directly available to ground forces.

Drawing: NRO, via Dwayne A. Day

URSALA

RAQUEL was more complex and expensive than URSULA, and was designed to search and locate emitters in the 4-18 GHz range, and also acquire technical intelligence on the discovered radars. Only two RAQUEL satellites were built and launched.

Drawing: NRO, via Dwayne A. Day

RAQUEL 1A

FARRAH

In the mid-1970s, the NRO had planned to end the P-11 SIGINT program after URSALA/RAQUEL, but this decision was reverted when it became clear how valuable the intelligence of the URSALA and RAQUEL assets was. It was decided to build a new payload, which combined the capabilities of the two systems. It was named FARRAH, and the first two satellites were launched in May 1982 and June 1984, respectively. They had a mass of about 700 kg (380 lb), and operated in orbits of about 700 km altitude. FARRAH 1 and 2 both remained active for more than 20 years. The tape recorders stopped working after less than 10 years, but the satellites could still work in transponder mode.

Drawings: NRO/NSA, via Gunter Krebs
FARRAH 1		FARRAH 3

The final three satellites of the Mission 7300 program, FARRAH 3, 4 and 5, were significantly different from the earlier ones. Because the HEXAGON program ended in the early 1980s, the NRO's small SIGINT satellites needed a new way to get into space. The Space Shuttle was initially selected as launch vehicle, and the basic satellite bus was significantly redesigned to make use of the Shuttle's payload weight and volume capabilities. The satellites were cylindrical instead of rectangular, and were much larger and heavier than FARRAH 1/2, with an in-orbit weight of more than 1360 kg (3000 lb). FARRAH 3 to 5 used three dish antennas to cover a total frequency range of 0.8-18 GHz. When Shuttle launches into polar orbits were abandoned after the Challenger disaster, Mission 7300 was switched to Titan 2(23)G launch vehicles. FARRAH 3 and 5 were successfully launched in September 1988 and April 1992, respectively, but FARRAH 4 failed because it didn't activate itself after reaching orbit. It is unknown, if and when FARRAH 3 and FARRAH 5 ceased to operate.

P-11 Launch List

• No.: Sequential flight number for the P-11 program
• P-11: Vehicle serial number of the P-11 satellite bus
• Payload Name: Name of the NRO payload on this satellite. Some P-11 missions carried two payloads on one satellite.
• Satellite Name: The OPS number ("OPS" standing for "Operations") is a random number given to all military-related satellite launches between 1963 and May 1984 (when "OPS" was replaced by a sequential "USA" number).
• Mission: Each NRO payload of Program 989 had a unique NRO Mission number in the 73xx range. This doesn't apply to a few early P-11 flights by the Air Force for test or scientific purposes.
• COSPAR ID: International designation of the satellite; not applicable, if orbit was not reached

P-11 launches

^* It is unclear, if the "P-11" label still applied to the significantly redesigned FARRAH 3 to 5 satellite bus.
^† Mission number 7350 is not confirmed, but is inferred from the assumed continuity of the series.

Main Sources

[1] Dwayne A. Day: Little Wizards: Signals intelligence satellites during the Cold War, The Space Review, August 2021
[2] Dwayne A. Day: Wizards redux: revisiting the P-11 signals intelligence satellites, The Space Review, September 2021
[3] Dwayne A. Day: Buccaneers of the high frontier: Program 989 SIGINT satellites from the ABM hunt to the Falklands War to the space shuttle, The Space Review, November 2022
[4] Dwayne A. Day: Stars in the sky: The top secret URSALA, RAQUEL, and FARRAH satellites from the 1970s to the 21st century, The Space Review, March 2025
[5] David D. Bradburn et.al.: The SIGINT Satellite Story, NRO, 1994
[6] Mission 7300 Evolution, NRO
[7] A Brief History of the LEO Program, NRO, August 1991
[8] Various other declassified NRO documents

Back to Directory of U.S. Military Rockets and Missiles, Appendix 3

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Last Updated: 10 August 2025