Venera-13 mass spectrometer studies of atmospheric gases on Venus

Early in the morning of 1 March 1982, the descent vehicle of the Venera 13 station entered the dense layers of the planet's atmosphere. At an altitude of about 23 km above the surface of Venus, a mass spectrometer was turned on. The mass spectra being received was identified peaks of isotopes of neon-20 and neon-22. This information, received within less than 15 minutes after the instrument was turned on meant the isotopic composition of neon (one of the rare gases) was present in negligible amounts in the atmosphere of the planet that is our closest neighbor.