The reason for the surprising result measured by the Viking Lander spacecraft on Mars,that the pressure readings of the atmosphere seemed to go down continuously after the spacecraft landed,is that A) the sensors were measuring outgassing of the spacecraft as it adjusted to the very low atmospheric pressure on Mars. B) the sensors were slowly deteriorating in the intense solar UV radiation,making them progressively less sensitive. C) the major constituent of the atmosphere,CO₂,was freezing into dry ice flakes as winter approached. D) the wake caused by the landing of the spacecraft acted like a hole in the atmosphere to allow the surface gases to escape.

Question

Quizplus · Accepted Answer

The major constituent of the atmosphere on Mars is carbon dioxide, which can freeze into dry ice as temperatures drop. As the winter approached, it is likely that carbon dioxide was freezing out of the atmosphere and onto the surface, causing a drop in pressure readings.

The Reason for the Surprising Result Measured by the Viking