Venera


The Venera 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. Ten probes successfully landed on the surface of the planet, including the two Vega program and Venera-Halley probes, while thirteen probes successfully entered the Venusian atmosphere. 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, the first to make a soft landing on another planet, the first to return images from another planet's surface, and the first to perform high-resolution radar mapping scans.

The Venera probes

Venera 1 and 2

The first Soviet attempt at a flyby probe to Venus was launched on February 4, 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. 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 February 12, 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 November 12, 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.

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 human-made object to impact another planet's surface as it crash-landed on March 1, 1966. However, as the spacecraft's data probes had failed upon atmospheric penetration, no data from within the Venusian boundary were retrieved from the mission.
On 18 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 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.

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 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 high-speed zonal winds in the Venusian atmosphere.
Venera 7's parachute failed shortly before landing very close to the surface. It impacted at and toppled over, but survived. Due to the resultant antenna misalignment, the radio signal was very weak, but was detected for 23 more minutes before its batteries expired. Thus, it became, on 15 December 1970, the first human-made probe to transmit data from the surface of Venus.

Venera 8

, launched in 1972, was equipped with an extended set of scientific instruments for studying the surface. The cruise bus of Venera 7 and 8 was similar to that of earlier ones, with the design ascending to the Zond 3 mission. The lander transmitted data during the descent and landed in sunlight. It measured the light level but had no camera. It transmitted data for almost an hour.

Venera 9 to 12

Following the failed Kosmos 482, the 1976 Venera 9 and 10 probes and 1978 Venera 11 and 12 probes were of a different design. 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 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. All four landers had problems with some or all of their camera lens caps not releasing.
The Venera 9 lander operated for at least 53 minutes and took pictures with one of two cameras; the other lens cap did not release.
The Venera 10 lander operated for at least 65 minutes and took pictures with one of two cameras; the other lens cap did not release.
The Venera 11 lander operated for at least 95 minutes but neither cameras' lens caps released.
The Venera 12 lander operated for at least 110 minutes but neither cameras' lens caps released.

Venera 13 and 14

Venera 13 and 14 each had a descent craft/lander contained most of the instrumentation and electronics, and a flyby spacecraft that was used as a communications relay. The design was similar to the earlier Venera 9–12 landers. They carried instruments to take scientific measurements of the ground and atmosphere once landed, including cameras, a microphone, a drill and surface sampler, and a seismometer. They also had instruments to record electric discharges during its descent phase through the Venusian atmosphere.
The two descent craft landed about apart, just east of the eastern extension of an elevated region known as Phoebe Regio. The Venera 13 lander survived for 127 minutes, and the Venera 14 lander for 57 minutes, where the planned design life was only 32 minutes. The Venera 14 craft had the misfortune of ejecting the camera lens cap directly under the surface compressibility tester arm, and returned information for the compressibility of the lens cap rather than the surface. The descent vehicles transmitted data to the buses, which acted as data relays as they flew by Venus.

Venera 15 and 16

The 1983 Venera 15 and 16 spacecraft were orbiter missions; similar to previous probes, but the entry probes were replaced with surface imaging radar equipment. Radar imaging was necessary to penetrate the dense cloud of Venus.

VeGa probes

The VeGa 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" and "Gallei".

Future

Venera-D

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. Venera-D could incorporate some NASA components, including balloons, a subsatellite for plasma measurements, or a long-lived surface station on the lander.

Scientific findings

There were many scientific findings about Venus from the data retrieved by the Venera probes. For example, 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.

Venera camera successes and failures

The Venera 9 and 10 landers had two cameras each. However on both these missions, only one functioned because the lens covers failed to separate from the second camera on the landers. The design was changed for Venera 11 and 12, but on those missions all cameras failed. Venera 13 and 14 were the only landers on which all cameras worked properly; unfortunately, the titanium lens cap on Venera 14 landed precisely on the area which was targeted by the soil compression probe.

Types of Venera probes

Flight data for all Venera missions

NameMissionLaunchArrivalSurvival time minResultsOrbiter or probe Lander coordin.
1VA FlybyFebruary 4, 1961Failed to leave earth orbit
Venera 1FlybyFebruary 12, 1961Communications lost en route to Venus
Venera 2MV-1 No.1Atmospheric probeAugust 25, 1962Escape stage failed; Re-entered three days later
Venera 2MV-1 No.2Atmospheric probeSeptember 1, 1962Escape stage failed; Re-entered five days later
Venera 2MV-2 No.1FlybySeptember 12, 1962Third stage exploded; Spacecraft destroyed
Venera 3MV-1 No.2FlybyFebruary 19, 1964Did not reach parking orbit
Kosmos 27FlybyMarch 27, 1964Escape stage failed
Venera 2FlybyNovember 12, 1965Communications lost just before arrival
Venera 3Atmospheric probeNovember 16, 1965Communications lost just before atmospheric entry. This was the first manmade object to land on another planet on March 1, 1966. Probable landing region: -20° to 20° N, 60° to 80° E.
Kosmos 96Atmospheric probeNovember 23, 1965Failed to leave Earth orbit and reentered the atmosphere. Believed by some researchers to have crashed near Kecksburg, Pennsylvania, USA 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. The name is also given to other Soviet/Russian spacecraft that are intended to—and do reach Earth orbit.
Venera 4Atmospheric probeJune 12, 1967October 18, 1967The 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 167Atmospheric probeJune 17, 1967Escape stage failed; Re-entered eight days later
Venera 5Atmospheric probeJanuary 5, 1969May 16, 196953*Successfully returned atmospheric data before being crushed by pressure within of the surface. Landed at 3° S, 18° E.
Venera 6Atmospheric probeJanuary 10, 1969May 17, 196951*Successfully returned atmospheric data before being crushed by pressure within of the surface. Landed at 5° S, 23° E.
Venera 7LanderAugust 17, 1970December 15, 197023The 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 359LanderAugust 22, 1970Escape stage failed; Ended up in an elliptical Earth orbit
Venera 8LanderMarch 27, 1972July 22, 197250Landed within a radius of 10.70° S, 335.25° E.
Kosmos 482ProbeMarch 31, 1972Escape stage exploded during Trans-Venus injection; Some pieces re-entered and others remained in Earth orbit
Venera 9Orbiter and LanderJune 8, 1975October 22, 197553Sent back the first images of Venus' surface. Landed within a radius of 31.01° N, 291.64° E.
Venera 10Orbiter and LanderJune 14, 1975October 25, 197565Landed within a radius of 15.42° N, 291.51° E.
Venera 11Flyby and LanderSeptember 9, 1978December 25, 197895The lander arrived, but the imaging systems failed.
Venera 12Flyby and LanderSeptember 14, 1978December 21, 1978110The lander recorded what is thought to be lightning.
Venera 13Flyby and LanderOctober 30, 1981March 1, 1982127Returned the first colour images of Venus' surface, and discovered leucite basalt in a soil sample using a spectrometer.
Venera 14Flyby and LanderNovember 14, 1981March 5, 198257A soil sample revealed tholeiitic basalt.
Venera 15OrbiterJune 2, 1983October 10, 1983Mapped the northern hemisphere down to 30 degrees from North
Venera 16OrbiterJune 7, 1983October 14, 1983Mapped the northern hemisphere down to 30 degrees from North
Vega 1Flyby and LanderDecember 15, 1984June 11, 1985Part 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. See Vega 1.
Vega 2Flyby and LanderDecember 21, 1984June 15, 198556Part of the Vega program. The vessel was en route to Halley's Comet. See Vega 2.