Encyclopedia Astronautica

Russian gamma ray astronomy satellite. One launch, 1990.07.11. The Gamma USSR/France gamma/x-ray astronomical telescope spacecraft was derived from the Soyuz manned spacecraft and had an unusually long gestation.

The basic design was first conceived in 1965 as part of a 'Cloud Space Station' - a primary space station from which a number of man-tended, free-flying spacecraft would operated. This evolved by the early 1970's into the MKBS/MOK space station complex. Various spacecraft with specialized laboratories or instrument sets would fly autonomously away from the huge N1-launched main station. Gamma was originally to be a free-flyer of this complex. The Soyuz propulsion system was used, but the descent and orbital modules were replaced by a large pressurized cylinder containing the scientific instruments.

Work on the instrument payload for Gamma began in 1972, and French participation began in 1974. However that same year the N1 launch vehicle, and the MKBS space station, were cancelled.

The Soviet space program was completely reformulated in a resolution of February 1976, which included authorization to develop the free flyer in conjunction with the DOS-7/DOS-8 space station (which would eventually evolve into Mir). The draft project for Gamma was completed in 1978, and production was authorized together with Mir on 16 February 1979. At this point Gamma included a passive docking port so that the spacecraft could be serviced by Soyuz manned spacecraft. It was planned that at six and twelve months into its one year mission Gamma would be visited by a two-crew Soyuz, who would replace film cassettes and repair or replace instruments. This approach was dropped in 1982 when it became apparent that the spacecraft was overweight and that all planned Soyuz would be needed for support of the Mir station itself. All film systems were removed and replaced with purely electronic data return methods.

By that time Gamma was scheduled originally for launch in 1984, but further severe technical delays resulted in a 1990 launch, 35 years after it was first conceived. In the end the satellite's research in the field of high-energy astrophysics, conducted jointly with France and Poland, did not produce many noteworthy results.

Gamma offered the possibility of locating COS-B sources with a precision of a few arcminutes. The mission lasted ca. 2 years.


The science instrumentation included the Gamma-1 telescope (with a Telezvezda star tracker), the Disk-M telescope, and the Pulsar X-2 telescope. All 3 instruments were mounted coaxially on the observatory, allowing for simultaneous observation of any given region of the celestial sphere.

The Gamma-1 telescope was the principle instrument aboard the Gamma observatory. It was designed to perform detailed studies in the energy range 50 MeV - 6 GeV. The system consisted of 2 scintillation counters and a gas Cerenkov counter. It had an effective area of ~2000 sq-cm. Its angular resolution at 100 MeV was 1.5 degrees. The imaging field of view was +/- 2.5 degrees. The energy resolution was 12% at 100 MeV. Rather late in the game, it was decided to include a tungsten coded aperture mask which could be moved in and out of the field of view. The mask itself was made of 2 1-D masks each having a unit cell size of 1 mm. The basic resolution achieved by the mask was ~20 arcminutes for the weakest sources (4-sigma). Shortly after launch, the power to the spark chamber failed. This resulted in the angular resolution for most of the mission being only ~ 10 degrees. The telescope was a joint Soviet-French endeavor.

The Telezvezda star tracker worked together with the Gamma-1 telescope. It had a 6 deg x 6 deg field of view, and a 5th stellar magnitude sensitivity. It had an angular resolution of 2 arcmin, making it possible to determine the Gamma-1 pointing direction to the same accuracy.

The Disk-M telescope was designed to measure fluxes in the range 20 keV - 5 MeV. The detector consisted of NaI scintillation crystals. The angular resolution of the telescope was ~ 25 arcmin. The Disk-M telescope stopped working not long after launch.

The Pulsar X-2 telescope covered 2-25 keV with ~ 30 arcmin resolution and a 10 deg x 10 deg field of view. The telescope was a joint Soviet-French endeavor.


Studies were made of the Vela pulsar, the galactic center region, the Cygnus binaries, the Heming gamma source in Taurus, and Her X-1. The observatory also gathered information about the high-energy emissions of the Sun during peak solar activity.

Gross mass: 7,350 kg (16,200 lb).
Height: 7.70 m (25.20 ft).
Span: 12.00 m (39.00 ft).
First Launch: 1990.07.11.
Number: 1 .

More... - Chronology...

Associated Countries
See also
  • Soyuz The Russian Soyuz spacecraft has been the longest-lived, most adaptable, and most successful manned spacecraft design. In production for fifty years, more than 240 have been built and flown on a wide range of missions. The design will remain in use with the international space station well into the 21st century, providing the only manned access to the station after the retirement of the shuttle in 2011. More...

Associated Launch Vehicles
  • Soyuz Russian orbital launch vehicle. The world's first ICBM became the most often used and most reliable launch vehicle in history. The original core+four strap-on booster missile had a small third stage added to produce the Vostok launch vehicle, with a payload of 5 metric tons. Addition of a larger third stage produced the Voskhod/Soyuz vehicle, with a payload over 6 metric tons. Using this with a fourth stage, the resulting Molniya booster placed communications satellites and early lunar and planetary probes in higher energy trajectories. By the year 2000 over 1,628 had been launched with an unmatched success rate of 97.5% for production models. Improved models providing commercial launch services for international customers entered service in the new millenium, and a new launch pad at Kourou was to be inaugurated in 2009. It appeared that the R-7 could easily still be in service 70 years after its first launch. More...
  • Soyuz 11A511U2 Russian orbital launch vehicle. Soyuz 11A511U2 used synthetic kerosene ('Sintin') in first stage for launch of premium reconnaisance satellite and manned payloads requiring just a bit more payload than the standard 11A511 could offer. Further use of the 11A511U2 abandoned in 1996 due to Sintin production stoppage. Later Soyuz spacecraft launched on standard Soyuz, with reduced payload and rendezvous with Mir in lower orbit accepted. More...

Associated Manufacturers and Agencies
  • Korolev Russian manufacturer of rockets, spacecraft, and rocket engines. Korolev Design Bureau, Kaliningrad, Russia. More...
  • MOM Russian agency overseeing development of spacecraft. Ministry of General Machine Building (Moskva, Russia), Moscow, Russia. More...

  • McDowell, Jonathan, Jonathan's Space Home Page (launch records), Harvard University, 1997-present. Web Address when accessed: here.
  • JPL Mission and Spacecraft Library, Jet Propulsion Laboratory, 1997. Web Address when accessed: here.
  • Voevodin, Sergey A, "Sergey A. Voevodin's Reports", VSA072 - Space Apparatus, Web Address when accessed: here.
  • Hendrickx, Bart, "The Origins and Evolution of Mir and Its Modules", Journal of the British Interplanetary Society, Vol. 51, P. 203-222, 1998..
  • Siddiqi, Asif A, The Soviet Space Race With Apollo, University Press of Florida, 2003.

Associated Launch Sites
  • Baikonur Russia's largest cosmodrome, the only one used for manned launches and with facilities for the larger Proton, N1, and Energia launch vehicles. The spaceport ended up on foreign soil after the break-up of Soviet Union. The official designations NIIP-5 and GIK-5 are used in official Soviet histories. It was also universally referred to as Tyuratam by both Soviet military staff and engineers, and the US intelligence agencies. Since the dissolution of the Soviet Union the Russian Federation has insisted on continued use of the old Soviet 'public' name of Baikonur. In its Kazakh (Kazak) version this is rendered Baykonur. More...

Gamma Chronology

1976 February 17 - . LV Family: Energia; N1.
  • Energia; Buran; Mir; Luch; Potok approved; N1 formally cancelled. - . Nation: USSR. Spacecraft: Buran; Mir; Mir-2; Gamma; Potok; Luch. Central Committee of the Communist Party and Council of Soviet Ministers Decree 'On work on Energia-Buran, DOS-7K nos. 7 and 8, Gamma. Geyzer (Potok), and Altair (Luch) and cancellation of the N1' was issued. The design of an improved model of the Salyut DOS-17K space station was authorised as part of the third generation of Soviet space systems in a decree. At that time it was planned that the two stations (DOS-7 and DOS-8) would be equipped with two docking ports at either end of the station and an additional two ports at the sides of the forward small diameter compartment. Luch and Potok were elements of the second generation global command and control system (GKKRS) deployed in the first half of the 1980's. Luch satellites, analogous to the US TDRS, provided communications service to the Mir space station, Buran space shuttle, Soyuz-TM spacecraft, military satellites, and the TsUPK ground control center. They also served to provide mobile fleet communications for the Soviet Navy. Additional Details: here....

1990 July 11 - . 10:00 GMT - . Launch Site: Baikonur. Launch Complex: Baikonur LC1. LV Family: R-7. Launch Vehicle: Soyuz 11A511U2.
  • Gamma - . Payload: Gamma s/n 1L. Mass: 7,350 kg (16,200 lb). Nation: USSR. Agency: MOM. Class: Astronomy. Type: X-ray astronomy satellite. Spacecraft: Gamma. Duration: 1,388.41 days. Decay Date: 1992-02-28 . USAF Sat Cat: 20683 . COSPAR: 1990-058A. Apogee: 387 km (240 mi). Perigee: 382 km (237 mi). Inclination: 51.6000 deg. Period: 92.30 min. Spacecraft mission was research in the field of high-energy (gamma/x-ray) astrophysics conducted jointly with France and Poland. The satellite was based on the Soyuz manned spacecraft and had an extremely long gestation - conceived in 1965, authorised in 1976, scheduled originally for launch in 1984, but further severe technical delays resulted in a 1990 launch.

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