Jack, a professor emeritus at Princeton, died July 8, 2021, in Pennswood Village, Newtown, Pa., just two months short of his 99th birthday.

Born Sept. 3, 1922, in Cleveland, Ohio, Jack earned a bachelor’s degree in mathematics from Case Institute of Technology in 1951. He earned a Ph.D. in astrophysics from Princeton in 1954, followed by a postdoctoral fellowship awarded by the Carnegie Foundation. 

During his career at Princeton Jack took a lead in developing techniques suitable to space astronomy. His work with Stratoscope 1 and 2, in which a balloon lifted a telescope 80,000 feet above our atmosphere to film the surface of the sun, earned him the appointment of executive director of the Princeton Observatory’s space telescope program. That appointment led to NASA’s launch of the Copernicus Satellite in 1972, an orbiting astronomical observatory that produced significant advancement of knowledge to the astronomy community around the world. 

A Navy veteran, Jack loved music, reading, and travel, especially to countries where he could use his language skills.

Predeceased in 2012 by his wife of almost 70 years, Elizabeth, and his son Jerry, Jack is survived by sons John and Alan, four grandchildren, and six great-grandchildren.

Graduate memorials are prepared by the APGA.