Venera 9

• 1. Introduction

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  Venera 9 lifted off from Earth on the 8th of June, 1975. It carried a total mass of 4,936 kilograms and a mission unlike any before it. On the 22nd of October, at 05:13 UTC, its lander touched down on the surface of Venus. Within minutes, the first photograph ever taken from the surface of another planet was on its way to Earth. The image was black and white. It showed a slope covered in angular rocks, 30 to 40 centimeters across, with no trace of erosion. The rocks lay near a region called Beta Regio. No probe had ever photographed them before. The lander's survival was no accident, and those photographs were only part of what Venera 9 returned.

• 2. Surviving the Arrival

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  At 10.7 kilometers per second, the Venera 9 lander entered the Venusian atmosphere. Aerodynamic braking and a series of protective shells first reduced its speed to 150 meters per second. At 63 kilometers altitude, a three-domed parachute opened and slowed the lander to 50 meters per second. The descent through the cloud layer took about 20 minutes. Throughout that time, the lander measured the atmosphere and transmitted data to the orbiter overhead.

  At 50 kilometers altitude, the parachute was released. The Venusian atmosphere below the clouds is extraordinarily dense. A ring-shaped aerodynamic shield brought the lander down to just 7 meters per second before it reached the ground. A doughnut-shaped metal landing cushion absorbed the final impact by crumpling. Engineers had pre-cooled the lander's interior before entry. A system of circulating fluid then distributed heat during surface operations. Exactly 53 minutes of surface activity was what those measures achieved. When the orbiter passed out of radio range, contact was lost. The entry sphere carrying all of this hardware weighed 3,440 pounds. The surface payload inside it was 1,455 pounds.

• 3. The First Look

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  Two minutes after touchdown, Venera 9's cameras came online on a slope inclined at about 20 degrees. Scientists suspected the site was part of a tectonic rift valley called Aikhylu Chasma. The Sun was near zenith when the lander settled onto the surface. The surface appeared smooth in places but was covered with numerous stones. The lander recorded a light level of 14,000 lux, comparable to Earth in full daylight, though no direct sunlight reached the ground. No shadows fell in the images, and no dust was visible drifting in the air.

  Planned 360-degree panoramic photographs could not be completed. One of the two camera lens covers failed to open, limiting pictures to a 180-degree sweep. The same failure would repeat with Venera 10. The Venera 9 landing site was about 2,200 kilometers from where Venera 10 would set down.

• 4. In Orbit

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  The Venera 9 orbiter entered Venus orbit on the 20th of October, 1975. It was the first spacecraft ever to orbit Venus. Between the 26th of October and the 25th of December, 1975, the orbiter completed 17 survey missions. Its dual role was to act as a communications relay for the lander and to study the planet's cloud layers and atmospheric parameters directly.

  The 2.4-meter sphere mounted on top of the orbiter's cylinder had carried the lander until separation. Two solar panel wings and a high-gain parabolic antenna flanked the cylinder structure. A bell-shaped propulsion unit anchored the base. The instrument suite included infrared spectrometers and radiometers, ultraviolet photometers, photo-polarimeters, a triaxial magnetometer, and six electrostatic analyzers. Bistatic radar mapping and radio occultation experiments probed structural properties the cameras could not reach. Among the instruments was a Lyman-alpha spectrometer designed to measure the ratio of hydrogen to deuterium in the upper atmosphere.

• 5. A Poisoned Sky

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  Cloud layers between 30 and 40 kilometers thick covered Venus, their bases hovering 30 to 35 kilometers above the surface. The atmosphere beneath those clouds held hydrochloric acid, hydrofluoric acid, bromine, and iodine. Surface pressure measured about 90 atmospheres. Surface temperature reached 905 degrees Fahrenheit.

  The ISV-75 anemometer was among the instruments the lander carried to the surface, recording wind conditions within that chemical-laden atmosphere. The gamma-ray spectrometer and gamma-ray densitometer aboard the lander were alongside it, measuring the density and elemental composition of the rocks directly beneath the spacecraft.