Argon in the Martian atmosphere: Evidence from the Mars 6 descent module

In the descent of the automatic interplanetary station Mars 6, after parachute deployment, an analysis was carried out by means of a mass spectrometer, the analyzer of which was pumped out by a getter-ion pump. Unfortunately, mass spectra were not obtained. But during vehicle descent on a parachute tether, the pump discharge current was registered. The dynamics of the pump current at the end of descent operations imply that an inert gas is a basic component of the Martian atmosphere, along with CO₂. Laboratory post-experiment calibrations of other getter-ion pumps, performed with various mixtures of CO₂ and argon, result in a probable value of the argon content in the Martian atmosphere of 35 ± 10% by volume.