VanZandt, Thomas R. | Engineering Papers

NASA NTRS1995

Micro Weather Stations for Mars

A global network of weather stations will be needed to characterize the near-surface environment on Mars. Here, we review the scientific and measurement objectives of this network. We also show how these objectives can be met within the cost-constrained Mars Surveyor Program by augmenting the Mars Pathfinder-derived landers with large numbers of very small (less than 5 liter), low-mass (less than 5 kg), low-power, low-cost Mini-meteorological stations. Each station would include instruments for measuring atmospheric. pressures, temperatures, wind velocities, humidity, and airborne dust abundance. They would also include a data handling, telemetry, power, atmospheric entry, and deployment systems in a rugged package capable of direct entry and a high-impact landing. In this paper, we describe these systems and summarize the data-taking strategies and data volumes needed to achieve the surface meteorology objectives for Mars.

Crisp, David↗

NASA NTRS1994

High performance miniature hygrometer and method thereof

An uncoated interdigitated transducer is cooled from a temperature above the dew point to a temperature below the dew point, while a parameter of a signal of the transducer is measured. The reduction in temperature causes a monotonic change in transducer signal because that signal is sensitive primarily to the water loading of the transducer surface as water forms on that surface due to the reduction in temperature. As the dew point is approached with temperature reduction, the slope of the curve of transducer signal with respect to temperature, remains relatively constant. However, as the dew point is reached the slope of that curve increases and because of changes in the structure of the water layer on the surface of the transducer, at the dew point the transducer responds with a clear shift in the rate at which the transducer signal changes. The temperature at which the second derivative of signal vs. temperature peaks can be readily used to identify with extreme accuracy, the precise dew point. The measurement technique employed by the present invention is relatively immune to surface contamination which remains significantly unchanged during the brief measurement period.

VanZandt, Thomas R.↗