contributions to the optimal estimation of orbits of satellites and trajectories of missiles. Working in the fields of least-squares estimation and signal processing, Swerling published papers in 1958 and 1959 on "stagewise" smoothing, the first efforts to exploit the computational advantages of applying recursion to least-squares problems. His work, particularly "First-Order Error Propagation in a Stagewise Smoothing Procedure for Satellite Observations," anticipated that of Rudolf E. Kálmán, whose linear quadratic estimation technique became known as the Kalman filter. Swerling went on to participate in special studies and task forces for the Department of Defense in areas such as the Aegis Combat System and vulnerabilities of AWACS and Patriot missile systems to electronic countermeasures; he developed more sophisticated radar models for application to targets using stealth technology. Peter Swerling was a department manager for Conductron Corporation in Inglewood, California from 1961 to 1964. In 1966, he founded Technology Service Corporation in Santa Monica, California. With Swerling as president for 16 years, the company grew to 200 employees, had a successful IPO in 1983, and was acquired by Westinghouse Electric Corporation in 1985. In 1983, Swerling co-founded Swerling Manasse & Smith, Inc., in Canoga Park, California; he served as its president and CEO for 12 years from 1986 until his retirement in 1998. Beginning in 1965, for several years Swerling was an adjunct professor of electrical engineering at the University of Southern California; he taught advanced seminars in communication theory and served on doctoral committees. He was a founder and long-term trustee of Crossroads School, a K-12 private school prominent in the Los Angeles area. Recognition and assessment In 1978, Swerling was elected to membership in the National Academy of Engineering; election to the academy honors important contributions to engineering theory, as well as unusual accomplishments in developing fields of technology. Swerling was named a Fellow of the Institute of Electrical and Electronics Engineers in 1968 "for contributions to signal theory as applied to errors in tracking and trajectory prediction of missiles by radar;" he was recognized as a Life Fellow in 1994. Technology Service Corporation recognizes its founder by granting the Peter Swerling Award for Entrepreneurial Excellence to select employees who have made significant contributions to the growth and success of the company. Reviewing Swerling's impact, Solomon W. Golomb wrote that he was "probably the most influential radar theoretician of the second half of the 20th century, not only in the