Investigation of Venus with Venera-13 and -14 probes - First data on composition of rocks

The instrumentation, data, and calibration techniques for the rock analyses performed by the Venera 13 and 14 soft-Landers are described. Television images were obtained of the surface using three filters to produce true-color photographs, and an X ray fluorescence spectrometer was used to analyze soil samples. The fluorescence was induced by exposure of samples to Pu-238 (for lighter elements) and Fe-55 (for heavier elements). Proportional counters detected the emissions from the irradiated samples. The telemetered data were compared with laboratory simulations carried out to characterize the observed spectra. The Venera 13 was determined to have landed in a highland area composed, at the surface, of alkali basalt, a composition similar to that at the Venera 14 landing site, which was in a lowland area. A lack of surface water is suggested to have produced the uniform character of Venus surface rocks.