Strategic Pressure Measurement System Characterization of the Mars Entry Atmospheric Data System (MEADS)
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A primary flight science requirement of the Mars Science Laboratory (MSL) entry descent and landing instrumentation (MEDLI) project is the direct measurement of pressure at seven locations distributed across the heat shield during the entry and descent phases of the MSL mission. These direct pressure measurements, coupled with other sources of data, enable an estimates of the vehicle's orientation and of the atmospheric density. Estimating these parameters in flight reduces the uncertainty in the design and validation of a robust Mars entry system for future missions. A critical component to achieve these objectives is the experimental characterization of the pressure measurement system over the extreme environmental conditions to support rigorous estimates of pressure measurement uncertainty. The integrity of the mission results can be ensured by the experimental methods and analyses employed in the characterization. In this paper, we propose a systems engineering framework for the pre-flight experimental testing necessary to obtain an estimate of total measurement uncertainty; a framework that is broadly applicable to other instrumentation systems. This systematic approach translates project requirements into the statistical design of a series of experiments that efficiently characterizes the pressure system uncertainty and stability and requires minimal resources. Phases discussed in this paper include the experimental design and pre-execution evaluation, tactical execution protocols that defend against systematic sources, insightful analysis methods to quantify and interpret measurement system performance and sources uncertainty, and the integration of the characterization results into the flight data reduction algorithm thereby allowing for measurement uncertainty as a function of the flight trajectory. By employing a systems engineering viewpoint we seek to strategically allocate resources to meet the project requirements and ensure that the mission results are interpretable, reliable, and defendable.