Gamma

Drawing of theGamma space telescope satellite. The spaceframe and subsystems of the satellite were based on theProgress spacecraft
Operator	RKA
COSPAR ID	1990-058A
SATCATno.	20683
Mission duration	2 years
Spacecraft properties
Bus	Soyuz
Launch mass	7,350 kg (16,200 lb)[1]
Start of mission
Launch date	July 11, 1990 (1990-07-11)
Rocket	Soyuz-U2[2][3]
Launch site	BaikonurSite 1/5[3]
End of mission
Decay date	February 28, 1992 (1992-02-28)
Orbital parameters
Eccentricity	0.00326
Perigee altitude	190 km[2]
Apogee altitude	233 km[2]
Inclination	51.6°
Period	88.45  min
Main
Wavelengths	Gamma ray
Instruments
Gamma-1 telescope (50 MeV to 6 GeV)[4] Disk-M telescope (20 keV to 5 MeV)[4] Pulsar X-2 telescope (2–25 keV)[4]

Gamma was aSovietgamma ray telescope. It was launched on 11 July 1990 into an orbit aroundEarth with a height of 375 km and aninclination of 51.6 degrees. It lasted for around 2 years. On board the mission were three telescopes, all of which could be pointed at the same source. The project was a joint Soviet-French project.^[4]

The Gamma-1 telescope was the main telescope. It consisted of 2scintillation counters and a gasCerenkov counter. With an effective area of around 0.2 square metres (2.2 sq ft), it operated in the energy range of 50 MeV to 6 GeV. At 100 MeV it initially had anangular resolution of 1.5degrees, with afield of view of 5 degrees and an energy resolution of 12%. A Telezvezdastar tracker increased the pointing position accuracy of the Gamma-1 telescope to 2arcminutes by tracking stars up to anapparent magnitude of 5 within its 6 by 6 degree field of view. However, due to the failure of power to aspark chamber, for most of the mission the resolution was around 10 degrees.^[4]

The telescope was conceived in 1965, as part of the SovietCloud Space Station, which evolved into the Multi-module Orbital Complex (MOK).^[5]When work on Gamma finally began in 1972, it was intended to create aGamma observatory, the first space station module for MOK, the first modular space station in theSalyut programme.^[6]For this, it was designed to add the scientific instruments of the observatory to a spacecraft derived from theProgress spacecraft – with the Progress in turn being aSoyuz spacecraft derivate – and that this spacecraft would dock to a MOK space station. However, in 1974, at the time it became a joint venture with France, the MOK space station project was canceled, and in February 1976, the Soviet space program was reconfigured.When on 16 February 1979 production of the telescope was authorized, the plans for the Soviet space station modules had evolved to use theFunctional Cargo Block of theTKS spacecraft instead, with theKvant-1 Roentgen observatory eventually becoming the first such module forMir – as a result of these changes theGamma observatory was redesigned as the free flyingGamma satellite.At that time the telescope was authorized in 1979, it was planned to be launched in 1984, but the actual launch was delayed until 1990.

The Disk-M telescope operated in the energy range 20 keV – 5 MeV. It consisted ofSodium iodide scintillationcrystals, and had an angular resolution of 25 arcminutes. However, it stopped working shortly after the mission was launched.^[4]

Finally, the Pulsar X-2 telescope had 30 arcminute resolution and a 10 deg x 10 deg field of view, and operated in the energy range 2–25 keV.^[4]

Observations included studies of theVela Pulsar, theGalactic Center,Cygnus X-1,Hercules X-1 and theCrab Nebula. The telescopes also measured theSun during peaksolar activity.^[4]

• Aelita (spacecraft)

Wikimedia Commons has media related toGamma (satellite).

• Gamma on the Internet Encyclopedia of Science
• Gamma at Astronautix.com

• Gamma-ray telescopes
• Space telescopes
• Spacecraft launched in 1990
• Soviet space observatories
• France–Soviet Union relations

• Articles with short description
• Short description is different from Wikidata
• Commons category link is on Wikidata