Sputnik 21
Encyclopedia
Venera 2MV-2 No.1, also known as Sputnik 21 in the West, was a Soviet
spacecraft, which was launched in 1962 as part of the Venera
programme, and was intended to make a flyby of Venus
. Due to a problem with the rocket which launched it, it failed to leave low Earth orbit
, and reentered the atmosphere a few days later. It was the only Venera 2MV-2 spacecraft, both of which failed to leave Earth orbit.
Venera 2MV-2 No.1 was launched at 00:59:13 UTC on 12 September 1962, atop a Molniya
8K78 carrier rocket flying from Site 1/5
at the Baikonur Cosmodrome
. The rocket performed nominally up until cutoff of the Blok I stage, following injection into a low Earth orbit
. Following cutoff, one of the oxidiser valves failed to close, and liquid oxygen
was allowed to flow into the combustion chamber of one of the vernier thruster
s. The vernier thruster exploded, causing the rocket to tumble out of control. This led to the formation of bubbles in the upper stage oxidiser pump, which caused the upper stage engine to fail less than a second after ignition. It reentered the atmosphere on 14 September 1962, two days after it had been launched.
The designations Sputnik 25, and later Sputnik 21 were used by the United States Naval Space Command to identify the spacecraft in its Satellite Situation Summary documents, since the Soviet Union did not release the internal designations of its spacecraft at that time, and had not assigned it an official name due to its failure to depart geocentric orbit
.
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....
spacecraft, which was launched in 1962 as part of the Venera
Venera
The Venera series probes were developed by the Soviet Union between 1961 and 1984 to gather data from Venus, Venera being the Russian name for Venus...
programme, and was intended to make a flyby of Venus
Venus
Venus is the second planet from the Sun, orbiting it every 224.7 Earth days. The planet is named after Venus, the Roman goddess of love and beauty. After the Moon, it is the brightest natural object in the night sky, reaching an apparent magnitude of −4.6, bright enough to cast shadows...
. Due to a problem with the rocket which launched it, it failed to leave low Earth orbit
Low Earth orbit
A low Earth orbit is generally defined as an orbit within the locus extending from the Earth’s surface up to an altitude of 2,000 km...
, and reentered the atmosphere a few days later. It was the only Venera 2MV-2 spacecraft, both of which failed to leave Earth orbit.
Venera 2MV-2 No.1 was launched at 00:59:13 UTC on 12 September 1962, atop a Molniya
Molniya (rocket)
Molniya 8K78 was a modification of the well-known R-7 Semyorka rocket and had four stages.This derivative of the original three stage Vostok rocket was especially designed to bring high flying satellites into orbit or to launch probes to other planets. The first launch of this rocket was on...
8K78 carrier rocket flying from Site 1/5
Gagarin's Start
Gagarin's Start is a launch site at Baikonur Cosmodrome in Kazakhstan, used for the Soviet space program and now managed by the Russian Federal Space Agency....
at the Baikonur Cosmodrome
Baikonur Cosmodrome
The Baikonur Cosmodrome , also called Tyuratam, is the world's first and largest operational space launch facility. It is located in the desert steppe of Kazakhstan, about east of the Aral Sea, north of the Syr Darya river, near Tyuratam railway station, at 90 meters above sea level...
. The rocket performed nominally up until cutoff of the Blok I stage, following injection into a low Earth orbit
Low Earth orbit
A low Earth orbit is generally defined as an orbit within the locus extending from the Earth’s surface up to an altitude of 2,000 km...
. Following cutoff, one of the oxidiser valves failed to close, and liquid oxygen
Liquid oxygen
Liquid oxygen — abbreviated LOx, LOX or Lox in the aerospace, submarine and gas industries — is one of the physical forms of elemental oxygen.-Physical properties:...
was allowed to flow into the combustion chamber of one of the vernier thruster
Vernier thruster
A vernier thruster is a thruster used on a spacecraft for attitude control. It is a smaller thrust motor than main attitude control motors and is used for fine adjustments to the attitude or velocity of a spacecraft...
s. The vernier thruster exploded, causing the rocket to tumble out of control. This led to the formation of bubbles in the upper stage oxidiser pump, which caused the upper stage engine to fail less than a second after ignition. It reentered the atmosphere on 14 September 1962, two days after it had been launched.
The designations Sputnik 25, and later Sputnik 21 were used by the United States Naval Space Command to identify the spacecraft in its Satellite Situation Summary documents, since the Soviet Union did not release the internal designations of its spacecraft at that time, and had not assigned it an official name due to its failure to depart geocentric orbit
Geocentric orbit
A geocentric orbit involves any object orbiting the Earth, such as the Moon or artificial satellites. Currently there are approximately 2,465 artificial satellites orbiting the Earth and 6,216 pieces of space debris as tracked by the Goddard Space Flight Center...
.