Dr Arlin Krueger, the NASA scientist who developed the Total Ozone Mapping Spectrometer (TOMS), the instrument on the Nimbus-7 satellite that confirmed the existence of ozone depletion (the ozone hole) over Antarctica. Krueger has worked on ozone dynamics at NASA's Goddard Space Flight Center (GSFC) since 1969. He developed the Backscatter Ultraviolet (BUV) instrument, NASA's first space-based ozone probe carried on Nimbus-4. Krueger is photographed at GSFC next to a colour- coded map of TOMS ozone levels over Antarctica in 1987. Launched in 1978, TOMS continues (1991) to provide ozone data; Krueger is currently working on its successors for future launches.