USC Space Sciences

See also the Space Sciences Center

Work at USC in Space Sciences is focussed centrally in the Space Sciences Center which is directed by Professor Darrell L. Judge. The Center is engaged in both laboratory and space based investigations of photoabsorption and emission processes in atomic and molecular gases in the spectral region from the extreme ultraviolet through the infrared. Fundamental atomic and molecular constants and absolute specific cross sections are determined in the laboratory program using a broad range of experimental techniques. The deep space and sounding rocket flight experiments investigate the characteristics of planetary atmospheres, the interplanetary medium, and the sun through remote sensing optical techniques. Recently in situ neutral particle detection techniques have been developed to extend the capability of our remote sensing heliospheric space experiments. The Space Sciences Center also has a vigorous program in the physics of binary star systems and in the analysis of the luminosity variation of B and O type stars.

One of the projects in which the USC Space Sciences Center is involved is the International Extreme Ultraviolet Hitchhiker.

The Space Sciences group includes Professors Melvin Daybell and Darrell Judge, Research Professor Robert Wu, and Research Scientists Pradip Gangopadhyay, Howard Ogawa and Geraldine Peters.


Professor Melvin Daybell is interested in solar systems studies utilizing rocket and satellite borne photon spectrometers operating in the extreme ultraviolet. He and his students have developed a photoelectron spectrometer with two unique features for this work. It has no lenses, mirrors or gratings so that its performance will not deteriorate due to photo erosion of these elements during space missions lasting several years. Also, the overlap of spectra of different orders that plagues grating instruments is avoided. Studies of the long term dependence of the EUV spectrum of the sun, of particular importance for understanding of the behavior of the atmosphere of our earth and other planets, are contemplated.


Professor Darrell L. Judge is a spectroscopist with broad interests in astrophysical problems and laboratory atomic and molecular physics. He is the principal investigator for the ultraviolet photometric experiments on board Pioneers 10 and 11. Professor Judge is also the principal investigator for a sounding rocket program in which the influence of the highly time dependent extreme ultraviolet solar flux on the photo-chemistry of planetary atmospheres is investigated. In addition to his space research program Professor Judge conducts a major laboratory research effort in which the fundamental properties of atomic and molecular systems are determined. This research is carried out primarily in the extreme ultraviolet and soft x-ray spectral regions, using electron storage ring synchrotron radiation, tunable dye lasers, and a variety of conventional light sources. The results obtained include the identification of atomic and molecular energy levels, dynamics of atomic systems, specific absolute fragmentation cross sections, Frank-Condon factors, electronic transition moments, multiphoton absorption cross sections, and the determination of atomic and molecular constants.


Research Professor Robert Wu is a spectroscopist. His primary research interest is high resolution molecular spectroscopy from the extreme ultraviolet through the infrared -- especially as applied to small molecules of theoretical and astrophysical interest. Currently Dr. Wu's specific interests include the study of molecular metastables and free radicals in the gaseous phase, photon sputtering of molecular ices and clathrate hydrates, nonlinear laser spectrscopy of alkali metal vapors, and VUV laser frequency generation.

Other Departmental Research