Louis T. E. Thompson, 87, an authority in ballistic physics who worked on early rocket propellants and the famed Norden bombsight, died of pneumonia Dec. 13 at a Virginia Beach hospital.

He was on the staff of Naval Proving Ground at Dahlgren, Md., from 1923 to 1941. He was technical director of the Naval Ordnance Test Station in California from 1945 to 1952, and later served as member of the Defence Science Board and as a consultant to the Navy's bureau of naval weapons from the mid-1950s to mid-1960s.

In recent years, while attending scentific conferences here and abroad, he voiced his worries about the growth and increasing power of weapons systems.

During World War II, Dr. Thompson worked under Carl L. Norden as part of the team that developed the Norden bombsight.

The Norden sight combined an optical device, a gyroscope and a computer to provide a signal for dropping a bomb load automatically. It compensated for ground speed, drift, and otherwise imperceptible changes of altitude in its calculations.

Dr. Thompson's years at Dahlgren had included research into more powerful propellant systems for naval shells.

His work at Dahlgren grew out of his research at Clark University under Dr. Robert H. Goddard, after whom the Goddard Space Flight Center is named. While earning a master's degree in 1915 and a doctoral degree in physics two years later, Dr. Thompson assisted Goddard in his early research in rocket propulsion.

Dr. Thompson was a native of South Haven, Mich, and earned a bachelor's degree at Kalamazoo College.

His memberships included the American Physics Society and the American Academy for the Advancement of Science. He was member of the Cosmos Club in Washington.

Dr. Thompson received the government's Civilian Service Award in 1952 and the Navy's Distinguished Service Award in 1960.

He had maintained residences in Washington and Scardale, N. Y. He had spent recent years in Virginia Beach, where he enjoyed long walks, good cigars, and studying the stars.

Survivors include his wife, Margaret M., of the home; three daughters, Margaret T. Welford, of Richmond, Joan J. Hicks, of Urbana, III, and Anne T. Graves, of Williamsburg; a son, J Fraser, of Richmond; 14 grandchildren, and four great-grandchildren