The Venera 12 was an USSR unmanned space mission to explore the planet 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...

. Venera 12 was launched on 14 September 1978 at 02:25:13 UTC

Coordinated Universal Time

Coordinated Universal Time is the primary time standard by which the world regulates clocks and time. It is one of several closely related successors to Greenwich Mean Time. Computer servers, online services and other entities that rely on having a universally accepted time use UTC for that purpose...

. Separating from its flight platform on December 19, 1978, the lander entered the Venus atmosphere two days later at 11.2 km/s. During the descent, it employed aerodynamic braking followed by parachute braking and ending with atmospheric braking. It made a soft landing on the surface at 06:30 Moscow time (0330 UT) on 21 December after a descent time of approximately 1 hour. The touchdown speed was 7–8 m/s. Landing coordinates are . It transmitted data to the flight platform for 110 minutes after touchdown until the flight platform moved out of range. Identical instruments were carried on Venera 11

Venera 11

The Venera 11 was a USSR unmanned space mission part of the Venera program to explore the planet Venus. Venera 11 was launched on 9 September 1978 at 3:25:39 UTC....

 and 12.

Flight platform

Venera 12 flight platform carried solar wind detectors, ionosphere electron instruments and two gamma ray burst

Gamma ray burst

Gamma-ray bursts are flashes of gamma rays associated with extremely energetic explosions that have been observed in distant galaxies. They are the most luminous electromagnetic events known to occur in the universe. Bursts can last from ten milliseconds to several minutes, although a typical...

 detectors - the Soviet-built KONUS and the French

France

The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

-built SIGNE 2. The SIGNE 2 detectors were simultaneously flown on Venera 12 and Prognoz 7 to allow triangulation of gamma ray sources. Before and after Venus flyby, Venera 11 and Venera 12 yielded detailed time-profiles for 143 gamma-ray bursts, resulting in the first ever catalog of such events. The last gamma-ray burst reported by Venera 12 occurred on January 5, 1980. Venera 12 used its ultraviolet spectrometer to study Comet Bradfield on 13 February 1980, and reported spectrophotometric data until 19 March 1980.

List of flight platform instruments and experiments:

• 30-166 nm Extreme UV Spectrometer
• Compound Plasma Spectrometer
• KONUS Gamma-Ray Burst Detector
• SNEG Gamma-Ray Burst Detector
• Magnetometer
• 4 Semiconductor Counters
• 2 Gas-Discharge Counters
• 4 Scintillation Counters
• Hemispherical Proton Telescope

The mission ended in April, 1980.

Lander

The Venera 12 descent craft carried instruments designed to study the detailed chemical composition of the atmosphere, the nature of the clouds, and the thermal balance of the atmosphere.
Among the instruments on board was a gas chromatograph to measure the composition of the Venus atmosphere, instruments to study scattered solar radiation and soil composition, and a device named Groza which was designed to measure atmospheric electrical discharges. Results reported included evidence of lightning and thunder, a high Ar³⁶/Ar⁴⁰ ratio, and the discovery of carbon monoxide at low altitudes.
Both Venera 11 and Venera 12 had landers with two cameras, each designed for color imaging. Each failed to return images when the lens covers did not separate after landing due to a design flaw.

List of lander experiments and instruments:

• Backscatter Nephelometer
• Mass Spectrometer - MKh-6411
• Gas Chromatograph - Sigma
• X-Ray Fluorospectrometer
• 360° Scanning Photometer - IOAV
• Spectrometer (430-1170 nm)
• Microphone/Anemometer
• Low-Frequency Radio Sensor
• 4 Thermometers
• 3 Barometers
• Accelerometer - Bizon
• Penetrometer - PrOP-V
• Soil Analysis Device
• 2 Color Cameras
• Small solar batteries - MSB