Characterizing the Martian Environment Through Surface Spacecraft Observations

Over the course of a Mars Year (MY) atmospheric temperatures vary enough between the furthest (Aphelion) and closest (Perihelion) points in Mars' orbit due to an Earth-like obliquity and elliptical orbit, creating two distinct seasons. Aphelion has cooler temperatures and a cross-equatorial Hadley cell revealing equatorial water-ice clouds. Perihelion has warmer temperatures that support increased dust activity such as dust-devils or dust storms. These two seasons have been observed from orbit and surface, with surface vehicles crucially important for understanding surface-to-atmosphere interactions. Aerosols were examined for wind direction and speed using movies from the Mars Science Laboratory (MSL) rover and InSight lander due to their proximity. Similar Easterly wind directions during the Aphelion season for both landing sites helped pinpoint that observed aerosols were most likely aloft in the middle atmosphere, affected by the same large-scale circulation via Hadley cells. However, mission constraints such as power and data volume limit the amount of returnable data and the ability to fully understand these aerosols. Automated methods appear to show promising results based on an algorithm developed by a team from Curtin university and tested with known wind directions from MSL atmospheric movies. The Onboard Rover Cloud Algorithm (ORCA) could be used on future missions to significantly decrease data volume by simply returning a set of wind parameters without first downlinking images. To further expand low-cost options, an optical meteorological station was created based on the Phoenix Mars mission experiment that imaged the lidar beam shining within aerosols to calculate ice-water content. The Mars Atmospheric Panoramic camera and Laser Experiment (MAPLE) has a panoramic camera and multiple class 3R lasers to maximize returnable science in a minimal way. Field testing in dense fog in Newfoundland showed that MAPLE's lasers could detect fog decks up to 100 m above the camera during nighttime conditions. The lasers were unable to be resolved during the day, but a power calculation determined that all three lasers on MAPLE could be suitable for Martian polar conditions. Understanding the constraints of obtaining Martian atmospheric data enables low-cost options such as MAPLE to further our knowledge of these aerosols.