Venera

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Venera

The Venera (Russian: Венера;) series of probes was developed by the USSR to gather data from Venus. As with some of the USSR's other planetary probes, the later versions were launched in pairs with a second vehicle being launched soon (a week or two) after the first of the pair.

Among the other results, probes of the series became the first man-made devices to enter the atmosphere of another planet, to make a soft landing on another planet, to return images from the planetary surface and to perform high-resolution radar mapping studies of Venus. So, the entire series could be considered as highly successful. Unfortunately, while Venus' orbit is closer to Earth than Mars, its surface conditions were far more extreme, which often meant that the probes did not survive long.

Venera is the Russian name for Venus.

The Venera probes

Venera 3 to 6

The Venera 3 to 6 probes were similar. Weighing approximately one ton, and launched by the Molniya -type booster rocket, they included a cruise "bus" and a spherical atmospheric entry probe. The probes were optimised for atmospheric measurements, but not equipped with any special landing apparatus. Although it was hoped they would reach the surface still functioning, the first probes failed almost immediately, thereby disabling data transmission to Earth.

Venera 3 became the first manmade object to impact another planet's surface as it crash-landed on March 1, 1966. However, as the spacecraft's dataprobes had failed upon atmopheric penetration, no data from within the Venusian boundary was retrieved from the mission.

In October 1967, Venera 4 became the first spacecraft to measure the atmosphere of another planet. While the Soviet Union initially claimed the craft reached the surface intact, re-analysis including atmospheric occultation data from the American Mariner 5 spacecraft that flew by Venus the day after its arrival demonstrated that Venus's surface pressure was 75-100 atmospheres, much higher than its 25 atm hull strength, and the claim was retracted.

Realizing the ships would be crushed before reaching the surface, Russia launched Venera 5 and Venera 6 as atmospheric probes. Designed to jettison nearly half their payload prior to entering the planet's atmosphere, these craft recorded 53 and 51 minutes of data, respectively, before their batteries failed.

Venera 7

The Venera 7 probe was the first one designed to survive Venus surface conditions and to make a soft landing. Massively overbuilt to ensure survival, it had few experiments on board, and scientific output from the mission was further limited due to an internal switchboard failure which stuck in the "transmit temperature" position. Still, the control scientists succeeded in extrapolating the pressure (90 atm) from the temperature data (465°C) , which resulted from the first direct surface measurements. The Doppler measurements of the Venera 4 to 7 probes were the first evidence of the existence of high-speed zonal winds (up to 100 m/s) in the Venus atmosphere (superrotation).

Venera 7's parachute failed shortly before landing, fortunately very close to the surface. It impacted at 17 m/s and toppled over, but survived. Due to the resultant antenna misalignment, the radio signal was very weak, but was detected (with temperature telemetry) for 23 more minutes before its batteries expired. Thus, it became, on 15 December 1970, the first man-made probe to transmit data from the surface of another planet.

Venera 8

Venera 8 was equipped with an extended set of scientific instruments for studying the surface (gamma-spectrometer etc.). The cruise bus of Venera 7 and 8 was similar to that of earlier ones, with the design ascending to the Zond 3 mission.

Venera 9 to 14

They weighed approximately five tons and were launched by the powerful Proton booster. They included a transfer and relay bus that had engines to brake into Venus orbit (Venera 9 and 10, 15 and 16) and to serve as receiver and relay for the entry probe's transmissions. The entry probe was attached to the top of the bus in a spherical heat shield. The probes were optimized for surface operations with an unusual looking design that included a spherical compartment to protect the electronics from atmospheric pressure and heat for as long as possible. Beneath this was a shock absorbing "crush ring" for landing. Above the pressure sphere was a cylindrical antenna structure and a wide dish shaped structure that resembled an antenna but was actually an aerobrake. They were designed to operate on the surface for a minimum of 30 minutes. Instruments varied on different missions, but included cameras and atmospheric and soil analysis equipment.

Veneras 15 and 16

Veneras 15 and 16 were similar but replaced the entry probes with surface imaging radar equipment.

The Vega probes to Venus and comet Halley launched in 1985 also used this basic Venera design, including landers but also atmospheric balloons which relayed data for about two days.

Venera camera failures and success

The Venera 9 and 10 landers had two cameras each. Only one functioned because the lens covers failed to separate from the second camera on each lander. The design was changed for Venera 11 and 12, but this made the problem worse and all cameras failed on those missions. Venera 13 and 14 were the only landers on which all cameras worked properly; although ironically, the lens cap on Venera 14 landed exactly in the way of the soil compression probe...

The external link at the bottom of the page shows all lander imagery.

Flight data for all Venera missions

1VA (proto-Venera) - Flyby - launched February 4, 1961 : Failed to leave earth orbit
Venera 1 - Flyby - launched February 12, 1961 : Communications lost en route to Venus
Sputnik 19 - Atmospheric Probe - launched August 25, 1962 : Escape stage failed; Re-entered three days later
Sputnik 20 - Atmospheric Probe - launched September 1, 1962 : Escape stage failed; Re-entered five days later
Sputnik 21 - Flyby - launched September 12, 1962 : Third stage exploded; Spacecraft destroyed
Cosmos 21 - Flyby - launched November 11, 1963 : Escape stage failed; Re-entered three days later
Venera 1964A - Flyby - launched February 19, 1964: Did not reach parking orbit
Venera 1964B - Flyby - launched March 1, 1964 : Did not reach parking orbit
Cosmos 27 - Flyby - launched March 27, 1964 : Escape stage failed
Venera 2 - Flyby - launched November 12, 1965 : Communications lost just before arrival
Venera 3 - Atmospheric Probe - launched November 16, 1965 : Communications lost just before atmospheric entry. This was the first manmade object to land on another planet on March 1966 (crash). Probable landing region : -20º to 20º N, 60º to 80º E.
Cosmos 96 - Atmospheric Probe - launched November 23, 1965 : Failed to leave Earth orbit, and reentered the atmosphere. Believed by some researchers to have crashed near Kecksburg, Pennsylvania on December 9, 1965, an event which became known as the "Kecksburg Incident" among UFO researchers. All Soviet spacecraft that never left Earth orbit were customarily renamed "Kosmos" regardless of the craft's intended mission.
Venera 1965A - Flyby - launched November 26, 1965 : Launcher failed
Venera 4 - Atmospheric Probe - launched June 12, 1967 : Arrived October 18, 1967 and was the first probe to enter another planet's atmosphere and return data. Although it did not transmit from the surface, this was the first interplanetary broadcast of any probe. Landed somewhere near latitude 19° N, longitude 38° E.
Cosmos 167 - Atmospheric Probe - launched June 17, 1967 : Escape stage failed; Re-entered eight days later
Venera 5 - Atmospheric Probe - launched January 5, 1969 : Arrived May 16, 1969 and successfully returned atmospheric data before being crushed by pressure within 26km of the surface. Landed at 3° S, 18° E.
Venera 6 - Atmospheric Probe - launched January 10, 1969 : Arrived May 17, 1969 and successfully returned atmospheric data before being crushed by pressure within 11km of the surface. Landed at 5° S, 23° E.
Venera 7 - Lander - launched August 17, 1970 : Arrived December 15, 1970, was the first successful landing of a spacecraft on another planet and survived for 23 minutes before succumbing to the heat and pressure. This was the first broadcast from another planet's surface. Landed at 5° S, 351° E.
Cosmos 359 - Lander - launched August 22, 1790 : Escape stage failed; Ended up in an elliptical Earth orbit
Venera 8 - Lander - launched March 27, 1972 : Arrived July 22, 1972 and survived for 50 minutes before succumbing to the heat and pressure. Landed within a 150 km radius of 10.70° S, 335.25° E.
Cosmos 482 - Probe - launched March 31, 1972 : Escape stage exploded during Trans-Venus injection; Some pieces re-entered and others remained in Earth orbit
Venera 9 - Orbiter and Lander - launched June 8, 1975 : Arrived October 22, 1975, sent back the first (black and white) images of Venus' surface while the lander survived 53 minutes before succumbing to the heat and pressure. Landed within a 150km radius of 31.01° N, 291.64° E.
Venera 10 - Orbiter and Lander - launched June 14, 1975 : Arrived October 25, 1975, the lander surviving 65 minutes before succumbing to the heat and pressure. Landed within a 150 km radius of 15.42° N, 291.51° E.
Venera 11 - Flyby and Lander - launched September 9, 1978 : Arrived December 25, 1978, the lander survived for 95 minutes; however the imaging systems had failed. Landed at 14° S 299° E.
Venera 12 - Flyby and Lander - launched September 14, 1978 : Arrived December 21, 1978, the lander surviving for 110 minutes and recorded what is thought to be lightning. Landed at 7° S 294° E.
Venera 13 - Flyby and Lander - launched October 30, 1981 : Arrived March 1, 1982, returned the first colour images of Venus' surface and discovered leucite basalt in a soil sample using a spectrometer. Landed at 7.5° S, 303° E
Venera 14 - Flyby and Lander - launched November 14, 1981 : Arrived March 5, 1982, a soil sample revealed tholeiitic basalt (similar to that found on Earth's mid-ocean ridges). Landed at 13.25° S, 310° E.
Venera 15 - Orbiter - launched June 2, 1983 : Arrived October 10, 1983 and mapped (along with Venera 16) the northern hemisphere down to 30 degrees from North (resolution 1-2km)
Venera 16 - Orbiter - launched June 7, 1983 : Arrived October 14, 1983 and mapped (along with Venera 15) the northern hemisphere down to 30 degrees from North (resolution 1-2km)

External links

Venera programme

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