William Lincoln

A Systems Engineering Approach to Estimating Uncertainty in Above-Ground Biomass AGB Derived from Remote-Sensing Data

We integrate systems of measurement and modeling to improve estimation of uncertainties in above-ground biomass AGB derived from remote sensing. The outcome provides a unified starting point for the climate-change carbon community to assess uncertainty and sensitivity data and methodologies, and ultimately supports decision-making about which missions and instruments to develop for a desired cost/benefit ratio. Initial results include fusion of remote-sensing techniques e.g., radar and lidar, uncertainties associated with measurement and modeling, and the impact of potential uncertainty correlations across aggregated unit areas. Biomass uncertainty estimates are presented at the single-hectare level for the forestlands of California. Using a forest biomass map of California, we calculate changes in variance e.g., 2 orders of magnitude as a function of uncertainty correlation assumptions, with correlations extending to spatial scales up to 100 km. Using a variogram formalism to derive the correlation shape and magnitude, we show that the estimated variance for California above-ground biomass is between 1% and 2% 1 standard deviation for our current best estimate of the correlation range at 5-10 km-i.e., we bound the standard deviation by a factor of 2. This contrasts with 0.025% 1 standard deviation if one does not include the correlation term.

Analysis of Concepts for Large-Scale Robotic Lunar Precursor Missions

Two concepts for large-scale, complex, robotic missions to search for frozen water at the lunar South Pole are systematically analyzed to determine their relative productivity and investment requirements. The Strategic Assessment of Risk and Technology (START) methodology and tool are utilized to determine temporal R&D-investment recommendations to optimize mission performance goals subject to budget, workforce, and other non-technical constraints. Explicit distinction is made between enabling and enhancing technologies. Uncertainties and dependencies are included within the optimization framework. This study determined that given the constraints used in this analysis, the longer mission would return 12 times the value of the shorter mission for roughly an 11% increase in cost, and would be enabled with the recommended temporal technology portfolio.

Temporal investment strategy to enable JPL future space missions

The Jet Propulsion Laboratory (JPL) formulates and conducts deep space missions for NASA (the National Aeronautics and Space Administration). The chief technologist of JPL has the responsibility for strategic planning of the laboratorys advanced technology program to assure that the required technological capabilities to enable future JPL deep space missions are ready as needed; as such he is responsible for the development of a Strategic Plan. As part of the planning effort, he has supported the development of a structured approach to technology prioritization based upon the work of the START (Strategic Assessment of Risk and Technology) team. A major innovation reported here is the addition of a temporal model that supports scheduling of technology development as a function of time. The JPL Strategic Technology Plan divides the required capabilities into 13 strategic themes. The results reported here represent the analysis of an initial seven

Comparative analysis of asteroid-deflection approaches

Five potential methods of preventing an asteroid from colliding with Earth-Kinetic Impactor (KI), Ion Beam Deflection (IBD), Gravity Tractor (GT), Enhanced Gravity Tractor (EGT), and Laser Ablation (LA)-are compared, with the objective of helping to inform a NASA decision regarding which technology or technologies could be demonstrated in space on the proposed 2019 Asteroid Robotic Redirect Mission (ARRM). Three design blocks are considered, which differ in the power available to the deflection technology and the mass at low-Earth orbit. We plot the required warning time (up to 30 years between discovery of the hazard and potential collision with Earth) vs. asteroid diameter for each of four technologies (gravity tractor without enhancement is considered only as a trim/verification candidate) under each design block, and illustrate sensitivities of results to important parameters.

Mobility productivity impacts on selection of lunar exploration architectures

The productivity of scientific exploration of the Moon and Mars has been significantly improved through the mobility of roving vehicles (rovers) since these vehicles allow scientists to conduct operations well beyond the immediate vicinity of the landing area. This paper reports on a quantitative approach developed to evaluate the productivity of alternative human and robot work-system alternatives for a lunar science mission. A graph-search approach for task planning was used for assigning human and robotic work systems to scientific tasks in order to evaluate the productivity of different mobility options. The results were used to identify the benefits and costs of alternative rover combinations in order to establish guidelines for the roles of the different vehicle types. Pressurized rovers displayed advantages over unpressurized rovers due to enhanced range and duration yielding more science productivity. Multiple pressurized rovers were found to be more productive than multiple unpressurized rovers.