Method, instruments, and results of the determination of elements contained in Venusian rock by the Vega-2 interplanetary probe

With an x-ray fluorescent spectrometer installed in the lander of the Vega-2 interplanetary station, elements contained in Venusian rock were determined for the northern part of Terra Aphroditae. The composition proved to be most similar to that of rocks of the anorthosite-norite-troctolite (ANT) group which constitute the basis of the moon's continental crust. The determination of the abundance of basic rock-forming elements from Mg to Fe, and also of some heavier rare elements, was carried out by x-ray-radiometry with the use of instruments installed in the lander. The measuring element included three radioisotope sources (one source of plutonium-238 and two sources of iron-55), four gas-discharge proportional counters, and soil collectors in which was placed the rock material to be analyzed