Kosmos 21
Soviet Venus probe stranded in Earth orbit.
Kosmos 21, also designated 3MV-1A and 3MV-1 No.1, was a Soviet spacecraft launched in 1963. It has been tentatively identified by NASA as a technology test for the Venera series, possibly intended as a Venus impact mission. The spacecraft never left Earth orbit and decayed three days after launch.
Quick Facts
- Operator
- OKB-1
- Satcat
- 00687
- Mission duration
- 3 days
- Launch mass
- 890 kg / 1,962 lb
- Launched
- 11 November 1963; 06:23:34 GMT
- Launch rocket
- Molniya 8K78M s/n G103-18
- Launch site
- Baikonur, Site 1/5
- Decay date
- 14 November 1963
Facts from the source article.
Spacecraft designation
Beginning in 1963, the Kosmos name was assigned to Soviet spacecraft that remained in Earth orbit, regardless of intended destination. Evidence from Soviet and non-Soviet sources indicates this mission was an intended planetary probe. Typically, Soviet planetary missions entered an Earth parking orbit before a four-minute engine burn launched them toward their target; misfires left probes in orbit with a Kosmos designation. The spacecraft's original development name was 3MV-1 No.1.
Design
Kosmos 21 was the first third-generation deep space probe of the 3MV series. Soviet engineers planned four 3MV types: 3MV-1 for Venus impact, 3MV-2 for Venus flyby, 3MV-3 for Mars impact, and 3MV-4 for Mars flyby. Compared to the second-generation 2MV probes, the 3MV series featured vastly improved orientation system elements and improved onboard propulsion. Two additional variants, 3MV-1A and 3MV-4A, were conceived as object-probes to verify key technologies during simpler deep-space missions. A government decree on 21 March 1963 approved two to three such missions; one 3MV-1A was designed to depart Earth's ecliptic out to 12–16 million kilometres and return after about six months, aided by two mid-course corrections using its S5.45 main engine, a lighter version of the 2MV engine with higher specific impulse and longer burn time.
Failure
The Soviets began their practice of hiding failed lunar and planetary missions with Kosmos names after this flight. The third and fourth stages separated incorrectly, and once in Earth orbit, ground controllers lost contact with the Blok L upper stage at 06:45:44 GMT. The stage’s main engine turbopump likely exploded when it ignited, destroying the spacecraft. Left stuck in Earth orbit, the craft had a perigee of 182 km and an apogee of 216 km, with an inclination of 64.8° and an orbital period of 88.5 minutes. It decayed on 14 November 1963. If it had successfully left orbit, it would probably have been called Zond 1.
More in Space Probes of ESA, Japan, China, India and the USSR
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