Developed strategic goals and scientific objectives for Cryospheric Sciences. Monitored the scope, budget and performance of the program. Developed and contributed inputs to intra- and inter-agency briefings, government reports and strategic plans. Participated in inter-agency activities to coordinate program implementation and to inform public policy related to the polar regions.Managed research grants made to various institutions through a peer-review selection process. Facilitated and led review panels, evaluating proposals for general cryosphere research, interdisciplinary studies, mission science teams, student fellowships and new investigator awards. Monitored technical and budget performance of selected awards, and recommended adjustments to ensure that overall program spending targets and scientific objectives were met.Communicated scientific results to a wide range of audiences within and outside the agency, at scientific conferences and through popular media. Contributed to technical and overview publications involving cryosphere-related science. Maintained briefing book on program highlights to support rapid response to requests from Congress and the White House Office of Science and Technology Policy.Facilitated community working groups, workshops and studies to address unresolved research challenges. Worked with international partners to foster collaboration, and to secure agreements for data access by funded investigators. Participated in site visits to NASA centers and academic institutions. Monitored technical performance and tracked science requirements for directed missions, such as ICESat-2 and the airborne Operation IceBridge. Ensured that science data products were accessible and met the needs of end users through collaboration with science data processing teams, and distributed active archive centers.

Promoted to Chief Scientist in January 2013; concurrently served in the NASA GSFC ICESat-2 Project Science Office and as Deputy Program Scientist for Cryospheric Sciences in the Earth Science Division at NASA HQ.Developed strategic goals and scientific objectives for the Cryospheric Sciences Program; monitored overall scope, budget and performance of the program; facilitated community studies and project assessments; managed research grants made to institutions and monitored performance of the selected investigators.Assumed leadership of the Program for Arctic Regional Climate Assessment and expanded its scope from a traditional Greenland focus to a broader synthesis of science across the Arctic.Represented NASA in the Interagency Arctic Research Policy Committee Review and Revisioning subgroup evaluating and updating the Arctic Research Plan; co-led a workshop for community stakeholders; and authored a chapter on sea level rise.Supervised team of scientists in a formal assessment of the airborne Operation IceBridge mission with the goal of bridging the gap between the ICESat and ICESat-2 satellite altimetry missions.Negotiated with the Polar Space Task Group to secure access to radar data collected by Canadian and European space agencies for NASA-funded investigators.Represented NASA in the Ice-sheet Mass Balance Intercomparison Exercise, organized by NASA and ESA to reach community consensus on ice-sheet mass loss as input to the Intergovernmental Panel on Climate Change.Provided expert technical expertise to the ICESat-2 Project Scientist during the mission design; reviewed spacecraft, instrument, and mission operations implementations to ensure that science requirements would be met; and worked with mission systems engineers to resolve problems that could impact science objectives.Oversaw teams responsible for ICESat-2 precision orbit and pointing determination; and monitored their technical, schedule, and cost performance.

Held a joint appointment to devise and evaluate methods for retrieving elevation change for ice sheets and glaciers using NASA ICESat and aircraft laser altimetry data.Conducted a comprehensive assessment of off-nadir laser-targeting performance during the ICESat mission and identified error contributions from the software and hardware systems involved with the planning and execution of attitude maneuvers.Invited by the NASA GSFC ICESat-2 project office to advise mission systems engineers in reviewing satellite vendor submissions under a Request for Information activity; conducted mission design trade studies for the Project Scientist and ad-hoc Science Team leader to examine potential concepts for the ICESat-2 mission; designed concepts of operations for the proposed mission with GSFC engineers; provided technical support for the Mission Concept Review and subsequent delta-Mission Concept Review.Served as principal author and co-investigator for a successful proposal to the NASA Cryospheric Sciences Program to compare data collected by ICESat and ESA’s CryoSat-2 radar altimetry satellite.

Provided expert technical advice and guidance to the NASA ICESat Science Team leader throughout the mission, and following launch, worked with the spacecraft vendor to develop the orbit acquisition plan.Performed precise orbit determination throughout the ICESat mission using GPS and ground-based satellite-laser-ranging observations; and explored improvements in orbit accuracy through tuning of geopotential fields and modeling the motion of Earth’s center of mass.Collaborated with the attitude determination team to overcome post-launch hardware anomalies and improve laser-pointing accuracy; and implemented improvements with the Mission Operations Center. Coordinated ground-based and airborne validation systems with satellite overflights to independently assess horizontal accuracy of derived individual laser footprint locations.Compared various models used to characterize the transformation between celestial and terrestrial reference frames; and published the results in a technical memorandum.Developed interface with the NASA GSFC science data processing team, including definitions of orbit and attitude data product formats and methods of exchange.

Conducted research in orbital mechanics; and investigated frozen orbit theory and precision orbit determination methodologies, including dissertation research on solar and Earth radiation pressure.Developed novel Monte Carlo Ray Tracing models to simulate forces on satellites induced by solar and Earth radiation pressure; and worked with a commercial vendor to implement models in the widely used Thermal Synthesizer System software.Designed calibration and mission orbits for the NASA ICESat mission and generated on-board reference ground tracks for targeting in the polar regions.

Developed mission design scenarios, including propellant budgets, ground station contacts, orbit acquisition strategies and maneuver planning; presented scenarios at major design reviews; acted as a customer interface; conducted on-site training for customer analysts; and served as lead orbit analyst during launch.Worked closely with NASA Glenn Research Center and NASA Johnson Space Center on deployment scenarios for the Advanced Communications Technology Satellite, which was successfully launched onboard the Space Shuttle Discovery during STS-51.Led a cross-functional team of engineers and software analysts in the development and validation of the Mission Analysis Software used to support launches and transfer orbit operations for the A2100 geosynchronous satellites.

Recruited through General Electric’s oldest and most selective corporate entry-level program, and completed three NASA-related rotational assignments within the Astro Space division: (1) Mechanical Systems, supporting the Chief Engineer in the Space Station program office; (2) Propulsion Systems, conducting acceptance test procedures for Mars Observer; (3) Mission Design and Analysis, developing deployment contingency scenarios for the Advanced Communications Technology Satellite.