Atmospheric dust is a more extreme modifier of weather and climate on Mars than water vapor is on Earth. Global dust storms enshroud Mars in a veil of dust for months and have major implications for past and present climate, geologic history, habitability, and exploration. Yet their mysterious origins mean we remain unable to realistically simulate or predict them. In this White Paper, we find that key Knowledge Gaps are: A. how dust is lifted; B. constraints on near-surface winds and boundary-layer processes; C. the distribution of mobile surface dust; and D. the key processes and feedbacks by which dust storms begin and evolve. To make progress in the next decade, we make four Recommendations in order of priority: #1. Properly accommodate a minimum payload of meteorological and aeolian sensors on future Mars surface missions; #2. Continue orbital monitoring of the evolving surface dust distribution; #3. Expand orbital measurements to include winds and full diurnal coverage; and #4. Continue orbital monitoring and add surface measurements of aerosols during dust storms.

The Sample Analysis at Mars (SAM) instrument is a suite of instruments aboard the Mars Science Laboratory that landed on Mars in 2012. Recent measurements of SAM inlet cover actuator temperatures during the 2018 Mars Global Dust Storm have shown less extreme, more benign effects that are beneficial to mechanism performance. These in-situ measurements and models developed from the current study can guide development of actuators and mechanisms on future robotic and manned mission to Mars. Deck-mounted actuators saw drastic, factor of two reduction in diurnal temperature range from 70C to 35C. Maximum temperatures were reduced from +10C to -10C due lower daytime air temperature and attenuation of solar flux absorbed by the actuator body due to increased opacity. Minimum temperatures increased from -60C to -45C due to warmer night-time air temperatures and an enhanced downwelling atmospheric radiation at the surface also caused by dust in the air. Another demonstration of the effects of the dust storm on inlet cover actuator temperature is the linear relation of optical depth plotted against logarithmic diurnal temperature range. Air-fall dust deposition on the white rover deck during the dust storm is indicated by scatter on this linear trend. Other constantly-monitored SAM temperatures include sensors on a second actuator that also shows the effects discussed above and two sensors mounted internally to SAM with less pronounced effects. In this work we will present an overview of the dust storm effects superimposed on the seasonal variation of actuator and other SAM temperatures.

All LIDAR instruments are not the same, and advancement of LIDAR technology requires an ongoing interest and demand from the community to foster further development of the required components. The purpose of this paper is to make the community aware of the need for further technical development, and the potential payoff of investing experimental time, money and thought into the next generation of LIDARs. Technologies for development: We advocate for future development of LIDAR technologies to measure the polarization state of the reflected light at selected multiple wavelengths, chosen according to the species of interest (e.g., H2O and CO2 in the Martian setting). Key scientific questions: In the coming decade, dollars spent on these LIDAR technologies will go towards addressing key climate questions on Mars and other rocky bodies, particularly those with seasonally changing (i.e. insolation driven) plumes of multiple icy volatiles such as Mars, Enceladus, Triton, or Pluto, and insolation-driven dust lifting, such as cometary bodies and the Moon. We will show from examining past Martian and terrestrial lidars that orbital and landed LIDARs can be effective for producing new insights into insolation-driven processes in current planetary climate on several bodies, beyond that available to our current fleet of largely passive instruments on planetary missions.