Observation Modes (IMAGE) Moscow Institute of Physics and Technology Caption Three observation modes of the Trace Gas Orbiter: the so-called solar occultation measurements (top right) of light passing through the Martian atmosphere and nadir, or 'straight-down,' measurements of reflected sunlight and Mars' own radiation from its dayside (left) and nightside (right). Credit MIPT Press Office Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.