Dr. Philip S. Callahan has worked at JPL for over 35 years. He is currently the Supervisor of the Radar Algorithms and Processing Group in the Radar Science & Engineering Section (334), with additional duties as Project Element Manager for the SeaWinds Ground System, Task Manager for Cassini Radar Instrument Operations, and a member of Ocean Surface Topography Science Team (OSTST).
Phil has worked on scatterometer data systems since 1983, when he helped with the proposal for the NASA Scatterometer (NSCAT) and then led the group developing algorithms for the data processing. He returned to scatterometry with the QuikSCAT and SeaWinds missions in 1997.
During a delay in the NSCAT program, Phil became the Measurement System Engineer for TOPEX. He worked with the Science Team and led the algorithm and data product definition for this first in the series of highly successful ocean altimeter missions. Phil continues as a member of the OSTST, refining the TOPEX data and investigating altimeter measurements in tropical storms.
In July 2003, Phil became the Task Manager for Cassini Radar Instrument Operations, managing the team generating sequences for radar observations, developing diagnostic and processing software, and carrying out the observations and instrument processing for operations. He has also worked with the Science Team in analysis of altimeter observations of Titan.
Phil has worked on proposals for several future missions including HYDROS (now SMAP), Ocean Vector Winds Mission, Wide Swath Ocean Altimeter for the Ocean Surface Topography Mission (now SWOT), and the Mars Scout Eagle.
Phil has received NASA Exceptional Service Medals in 2006 for Cassini and in 1994 for TOPEX
Phil and his wife have lived in Pasadena for the past 30 years, where they raised two sons. When not working, Phil enjoys physical fitness, gardening, and travel.
PhD - Caltech, Physics and Astronomy
BS - Cornell, Engineeering Physics
Radar Remote Sensing of oceans, mainly of wind and waves; phenomenology of corrections to radar remote sensing data; extraction of surface information from altimeter waveforms, including the Cassini Radar at Titan.
In addition to the work described above, Phil has worked in applications of Very Long Baseline Interferometry (VLBI) for Earth orientation measurements and spacecraft tracking. He has also worked on corrections to spacecraft tracking data for the Earth''s atmosphere and the solar wind plasma.
Lorenz, R.D., et al.,
"The Sand Seas of Titan: Cassini Radar Observations of Longitudinal Dunes,"
Science, 312, 724.
C. Elachi, S. Wall, M. Allison,Y. Anderson, R. Boehmer, P. Callahan, P. Encrenaz, E. Flamini, G. Francescetti, Y. Gim, G. Hamilton, S. Hensley, M. Janssen, W. Johnson, K. Kelleher, R. Kirk, R. Lopes, R. Lorenz, J. Lunine, D. Muhleman, S. Ostro, F. Paganelli, G. Picardi, F. Posa, L. Roth, R. Seu, S. Shaffer, L. Soderblom, B. Stiles, E. Stofan, S. Vetrella, R. West, C. Wood, L. Wye, and H. Zebker,
"Cassini Radar Views the Surface of Titan,"
Science, Vol. 308, No. 5724,
Rodriguez, E., and P.S. Callahan,
"Comparison of retracking of TOPEX and Jason-1 data,"
Marine Geodesy, 27, 391.
"chapter on the technical aspects of altimetry,"
Satellite Altimetry and Earth Sciences, ed. L-L. Fu and A. Cazenave, Academic Press.