Кеңес Одағының Венераны зерттеу бағдарламасы

Soviet program that explored Venus with multiple probes

The Venera (Lang ru, , which means "Venus" in Russian) program was the name given to a series of space probes developed by the Soviet Union between 1961 and 1984 to gather information about the planet Venus. Thirteen probes successfully entered the Venusian atmosphere, including the two Vega program and Venera Halley probes. Ten of those successfully landed on the surface of the planet. Due to the extreme surface conditions on Venus, the probes could only survive for a short period on the surface, with times ranging from 23 minutes to two hours. The Venera program established a number of precedents in space exploration, among them being the first human made devices to enter the atmosphere of another planet (Venera 3 on 1 March 1966), the first to make a soft landing on another planet (Venera 7 on 15 December 1970), the first to return images from another planet's surface (Venera 9 on 8 June 1975), the first to record sounds on another planet (Venera 13 on 30 October 1981), and the first to perform high resolution radar mapping scans (Venera 15 on 2 June 1983).

The first Soviet attempt at a flyby probe to Venus was launched on 4 February 1961, but failed to leave Earth orbit. In keeping with the Soviet policy at that time of not announcing details of failed missions, the launch was announced under the name Tyazhely Sputnik ("Heavy Satellite"). It is also known as Venera 1VA. As with some of the Soviet Union's other planetary probes, the later versions were launched in pairs, with a second vehicle launched soon after the first. Venera 1 and Venera 2 were intended to fly past Venus without entering orbit. Venera 1 was launched on 12 February 1961. Telemetry on the probe failed seven days after launch. It is believed to have passed within of Venus and remains in heliocentric orbit. Venera 2 launched on 12 November 1965, but also suffered a telemetry failure after leaving Earth orbit. Several other failed attempts at Venus flyby probes were launched by the Soviet Union in the early 1960s, but were not announced as planetary missions at the time, and hence did not officially receive the "Venera" designation.

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 human made object to impact another planet's surface as it crash landed on 1 March 1966. However, as the spacecraft's data probes had failed upon atmospheric penetration, no data from within the Venusian atmosphere were retrieved from the mission. On 18 October 1967, Venera 4 became the first spacecraft to measure the atmosphere of another planet. This spacecraft first showed the major gas of Venus's atmosphere to be CO2. 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 Venera 4's 25 atm hull strength, and the claim was retracted. Realizing the ships would be crushed before reaching the surface, the Soviets 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, while slowly descending by parachute before their batteries failed. Around that time it became increasingly known that Venus was unlikely to have liquid bodies of water, however the designs for the Soviet Venera probes still considered the possibility of a water landing as late as 1964.

The Venera 7 probe, launched in August 1970, was the first one designed to survive Venus's 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 that stuck in the "transmit temperature" position. Still, the control scientists succeeded in extrapolating the pressure (90 atm) from the temperature data with , 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 zonal winds with high speeds of up to 100 metres per second (330 ft/s, 362 km/h, 225 mph) in the Venusian atmosphere (super rotation). Along with the pressure and temperature data acquired Venera 7 also measured atmospheric composition. When the system was switched to radio altimeter mode the antenna operated at an 8 centimeter wavelength band to send and receive signals off of the Venusian surface over a period of 0.67 milliseconds. The results were a detailed map of the reflectivity distribution over the surface of the Venusian Northern Hemisphere. The linear distance measurements that were taken ranged from 91 to 182 kilometers. The twin Soviet spacecraft flew in near polar elliptical orbits and succeeded in mapping the top half of the northern atmosphere (from the north pole to 30 degrees N latitude, about 115 million square kilometers or 71 million square miles) by the end of the main mission. An altimeter provided topographical data with a height resolution of 50 m (164 feet), and an East German instrument mapped surface temperature variations.

The VeGa (Cyrillic: ВеГа) probes to Venus and comet 1/P Halley launched in 1984 also used this basic Venera design, including landers but also atmospheric balloons which relayed data for about two days. "VeGa" is an agglutination of the words "Venera" (Venus in Russian) and "Gallei" (Halley in Russian).

Venera D is a proposed mission to Venus that would include a highly capable orbiter and a lander. From the standpoint of total mass delivered to Venus, the best launch opportunities occur in 2026 and 2031; however, as of March 2021, Venera D is planned for launch no earlier than November 2029. Venera D could incorporate some NASA components, including balloons, a subsatellite for plasma measurements, or a long lived (24 hours) surface station on the lander.

There were many scientific findings from the data retrieved by the Venera probes making them pivotal in our understanding of Venus. The Venera probes provided direct data regarding Venus' surface and atmosphere while also providing important information on electronics lifetime under Venus' harsh conditions. Venera 4 was the first successful probe, and showed that CO2 is the main component in Venus' atmosphere. Venera 8 measured the K, U, and Th on the surface through gamma ray analysis. By sending the first images of Venus' surface back to Earth the Venera missions provided scientists with the ability to relay the achievements with the public. Venera 13 provided the first color images and X ray fluorescence data of the surface of the planet. After analyzing the radar images returned from Venera 15 and 16, it was concluded that the ridges and grooves on the surface of Venus were the result of tectonic deformations. This was found by radar imaging while in orbit. Even with their short lifetimes, the Venera missions each added significant understanding of our sister planet.

NameModel Mission Launch Arrival Survival time min Results Image Lander coordin. Venera 1VA No. 11VA No. 1 Flyby 4 February 1961 Failed to leave earth orbit Venera 11VA No. 2 Flyby 12 February 1961 Communications lost en route to Venus Venera 2MV 1 No.12MV 1 No.1 Atmospheric probe 25 August 1962 Escape stage failed; Re entered three days later Venera 2MV 1 No.22MV 1 No.2 Atmospheric probe 1 September 1962 Escape stage failed; Re entered five days later Venera 2MV 2 No.12MV 2 No.1 Flyby 12 September 1962 Third stage exploded; Spacecraft destroyed Venera 3MV 1 No.23MV 1 No.2 Flyby 19 February 1964 Did not reach parking orbit Kosmos 273MV 1 No.3 Flyby 27 March 1964 Escape stage failed Venera 23MV 4 No.4 Flyby 12 November 1965 Communications lost just before arrival Venera 33MV 3 No.1 Atmospheric probe 16 November 1965 Communications lost just before atmospheric entry. This was the first manmade object to land on another planet on 1 March 1966 (crash). Probable landing region: 20° to 20° N, 60° to 80° E. Kosmos 963MV 4 No.6 Atmospheric probe 23 November 1965 Failed to leave Earth orbit and reentered the atmosphere. Believed by some researchers to have crashed near Kecksburg, Pennsylvania, USA on 9 December 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. The name is also given to other Soviet/Russian spacecraft that are intended to—and do reach Earth orbit. Venera 44V 1 No.310 Atmospheric probe 12 June 1967 18 October 1967 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 transmission of any probe. Landed somewhere near latitude 19° N, longitude 38° E. Kosmos 1674V 1 No.311 Atmospheric probe 17 June 1967 Escape stage failed; Re entered eight days later Venera 52V (V 69) No. 330 Atmospheric probe 5 January 1969 16 May 1969 53* Successfully returned atmospheric data before being crushed by pressure within of the surface. Landed at 3° S, 18° E. Venera 62V (V 69) No.331 Atmospheric probe 10 January 1969 17 May 1969 51* Successfully returned atmospheric data before being crushed by pressure within of the surface. Landed at 5° S, 23° E. Venera 74V 1 No. 630 Lander 17 August 1970 15 December 1970 23 The first successful landing of a spacecraft on another planet, and the first transmission from another planet's surface. Survived for 23 minutes before succumbing to heat and pressure. Kosmos 3593V (V 70) Lander 22 August 1970 Escape stage failed; Ended up in an elliptical Earth orbit Venera 84V 1 No.670 Lander 27 March 1972 22 July 1972 50 Landed within a radius of 10.70° S, 335.25° E. Kosmos 4823V (V 72) no. 671 Probe 31 March 1972 Escape stage exploded during Trans Venus injection; Some pieces re entered and others remained in Earth orbit Venera 94V 1 No. 660 Orbiter and Lander 8 June 1975 22 October 1975 53 Sent back the first (black and white) images of Venus' surface. Landed within a radius of 31.01° N, 291.64° E. Venera 104V 1 No. 661 Orbiter and Lander 14 June 1975 25 October 1975 65 Landed within a radius of 15.42° N, 291.51° E. Venera 114V 1 No. 360 Flyby and Lander 9 September 1978 25 December 1978 95 The lander arrived, but the imaging systems failed. Venera 124V 1 Flyby and Lander 14 September 1978 21 December 1978 110 The lander recorded what is thought to be lightning. Venera 134V 1 no.760 Flyby and Lander 30 October 1981 1 March 1982 127 Returned the first colour images of Venus' surface, and discovered leucite basalt in a soil sample using a spectrometer. Venera 144V 1 No. 761 Flyby and Lander 14 November 1981 5 March 1982 57 A soil sample revealed tholeiitic basalt (similar to that found on Earth's mid ocean ridges). Venera 154V 2 No. 860 Orbiter 2 June 1983 10 October 1983 Mapped (along with Venera 16) the northern hemisphere down to 30 degrees from North (resolution 1–2 km) Venera 164V 2 Orbiter 7 June 1983 14 October 1983 Mapped (along with Venera 15) the northern hemisphere down to 30 degrees from North (resolution 1–2 km) Vega 15VK No. 902 Flyby and Lander 15 December 1984 11 June 1985 Part of the Vega program. The vessel was en route to Halley's Comet. During entry into atmosphere, the surface instruments began work early, and the lander failed. Vega 25VK No. 901Flyby and Lander 21 December 1984 15 June 1985 56 Part of the Vega program. The vessel was en route to Halley's Comet.