Results of the Venus sondes Venera 13 and 14

The voyage, experiments, and results of the Venera 13 and 14 expedition are described. The experimental equipment included a seismometer, a mass spectrometer for atmospheric analysis, an instrument to determine the physico-mechanical characteristics of the top layer of Venusian soil, a drilling device, and an X-ray fluorescence instrument for determing the chemical composition of the soil. The mother ship stayed at 36,000 km, as the landers entered the atmosphere at 11.1 km/s, slowing to 7.9 m/s at landing. Venera 13 landed in the Phoebe region and took eight photographs. Its soil analysis showed mainly leucitic basalt with high potassium and magnesium, but only 1.5 percent sodium. The temperature was 457 C. Venera 14 landed at 500 m higher alevation in a mountainous, crevasse-filled area. The soil was tholeiite, the pressure 94 bars, the temperature 465 C, and the ground illumination 5000 lux. Both landers measured the humidity at below 0.1 percent.