Istrebitel Sputnik , or IS ( meaning Satellite Fighter, after the meaning "Fighter aircraft

Fighter aircraft

A fighter aircraft is a military aircraft designed primarily for air-to-air combat with other aircraft, as opposed to a bomber, which is designed primarily to attack ground targets...

" for the Russian word istrebitel), was a Soviet

Soviet Union

The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....

 anti-satellite weapon

Anti-satellite weapon

Anti-satellite weapons are designed to incapacitate or destroy satellites for strategic military purposes. Currently, only the United States, the former Soviet Union, and the People's Republic of China are known to have developed these weapons. On September 13, 1985, the United States destroyed US...

s programme which led to the deployment of the IS-A

Is-a

In knowledge representation, object-oriented programming and design, is-a or is_a or is a is a relationship where one class D is a subclass of another class B ....

 or I2P system during the 1970s and 1980s. IS satellites were originally intended to launch on UR-200

UR-200

The UR-200 was an intercontinental ballistic missile developed by OKB-52 of Vladimir Nikolaevich Chelomey in the Soviet Union. It was known during the Cold War by the NATO reporting name SS-10 Scrag and internally by the GRAU index 8K81...

 rockets, but following the cancellation of the UR-200, the Polyot

Polyot (rocket)

The Polyot was an interim orbital carrier rocket, built to test ASAT spacecraft. It was required as a stopgap after the cancellation of the UR-200 programme, but before the Tsyklon could enter service. Only two were ever launched, the first on 1 November 1963, and the last on 12 April 1964...

, Tsyklon-2A and Tsyklon-2

Tsyklon-2

The Tsyklon-2, also known as Tsiklon-2 and Tsyklon-M, GRAU index 11K69, was a Soviet, and subsequently Ukrainian orbital carrier rocket. A derivative of the R-36 ICBM, and a member of the Tsyklon family, it made its maiden flight on 6 August 1969, and after 106 launches, made its final flight on 24...

 rockets were used instead.

The first test flights of the IS spacecraft used the I1P configuration, and served to demonstrate the propulsion and control systems of the spacecraft. Both were launched by Polyot rockets, and were designated Polyot 1 and Polyot 2. They were launched on 1 November 1963 and 12 April 1964 respectively. Following this, IS-A or I2P interceptors and IS-P or I2M targets were launched. Only four IS-P targets were launched before the type was replaced by the cheaper DS-P1-M satellite, launched as part of the Dnepropetrovsk Sputnik

Dnepropetrovsk Sputnik

Dnepropetrovsk Sputnik , also known as DS, was a series of satellites launched by the Soviet Union between 1961 and 1982. DS satellites were used for a number of missions, including technological and scientific research, and radar tracking targets for anti-satellite weapons and anti-ballistic...

 programme. Later IS-A tests intercepted DS-P1-M satellites, or the Lira satellites that succeeded them.