American Association for the Advancement of Science, Alvin Trivelpiece, became director of ORNL; he remained in the role until 2000. In 1992, a whistleblower, Charles Varnadore, filed complaints against ORNL, alleging safety violations and retaliation by his superiors. While an administrative law judge ruled in Varnadore's favor, the Secretary of Labor, Robert Reich, overturned that ruling. However, Varnadore's case saw prime contractor Martin Marietta cited for safety violations, and ultimately led to additional whistleblower protection within DOE. In January 2019 ORNL announced a major breakthrough in its capacity to automate Pu-238 production which helped push annual production from 50 grams to 400 grams, moving closer to NASA's goal of 1.5 kilograms per year by 2025 in order to sustain its space exploration programs. Areas of research ORNL conducts research and development activities that span a wide range of scientific disciplines. Many research areas have a significant overlap with each other; researchers often work in two or more of the fields listed here. The laboratory's major research areas are described briefly below. Chemical sciences – ORNL conducts both fundamental and applied research in a number of areas, including catalysis, surface science and interfacial chemistry; molecular transformations and fuel chemistry; heavy element chemistry and radioactive materials characterization; aqueous solution chemistry and geochemistry; mass spectrometry and laser spectroscopy; separations chemistry; materials chemistry including synthesis and characterization of polymers and other soft materials; chemical biosciences; and neutron science. Electron microscopy – ORNL's electron microscopy program investigates key issues in condensed matter, materials, chemical and nanosciences. Nuclear medicine – The laboratory's nuclear medicine research is focused on the development of improved reactor production and processing methods to provide medical radioisotopes, the development of new radionuclide generator systems, the design and evaluation of new radiopharmaceuticals for applications in nuclear medicine and oncology. Physics – Physics research at ORNL is focused primarily on studies of the fundamental properties of matter at the atomic, nuclear, and subnuclear levels and the development of experimental devices in support of these studies. Population – ORNL provides federal, state and international organizations with a gridded population database, called Landscan, for estimating ambient population. LandScan is a raster image, or grid, of population counts, which provides human population estimates every 30 x 30 arc seconds, which translates roughly to population estimates for 1 kilometer square windows or grid cells at the equator, with cell width decreasing at higher latitudes. Though many population datasets