THE CONTRIBUTIONS OF JOSHUA BANDFIELD TO OUR UNDERSTANDING OF MARS, THE MOON, AND SMALL BODIES
Early in his career, Josh pioneered the use of factor analysis and target transformation to determine atmospheric end members in Mars Global Surveyor Thermal Emission Spectrometer data, enabling the use of simple linear least squares models for atmospheric correction and estimation of surface emissivity. He used the same techniques to determine that most of the Martian surface could be modeled as basalt or basaltic andesite. These contributions enabled the work of dozens of additional researchers and led to decades of further analyses and refinements of compositional models of the Martian crust. Among his other accomplishments Josh also developed the methodologies for atmospherically correcting THEMIS data, used EPF measurements to characterize mm- to cm-scale surface roughness on Mars, and discovered and characterized quartzofeldspathic and hydrated silica-bearing martian terrains from thermal infrared data.
With the arrival of the Lunar Reconnaissance Orbiter Diviner Lunar Radiometer at the Moon in 2009, Josh used infrared measurements to make major contributions to our understanding of the lunar surface and its evolution over time. Josh produced the first global rock abundance maps of the Moon, estimated typical lunar surface roughness, and identified “cold spots” that have abnormally low temperatures in nighttime thermal infrared data. He found that these cold spots are associated with small, young craters, and hypothesized that they formed due to disturbance of the highly insulating lunar regolith. He recognized that their distribution could provide a key indicator of the timescales of modern regolith overturn on the Moon. In a major contribution to our understanding of the lunar volatile cycle, Josh developed a roughness-based thermal correction to M3 data that showed the widespread distribution of OH/H2O over the lunar surface.
In recent years, Josh carried over his work to understanding Mercury and small bodies. Josh’s contributions to planetary science have fundamentally changed the way we view terrestrial bodies in our solar system.