Russell S. (Russ) Ostrander, 68, a retired research engineer with the Johns Hopkins University Applied Physics Laboratory, died Monday at Holy Cross Hospital. He suffered from cancer.

He joined the laboratory in 1942 and worked on the early development of the proximity fuse. It carried a tiny radio set in the nose and exploded shells in the proximity of a target. Used in antiaircraft shells, it helped defeat the German buzz bomb, which heavily damaged London in World War II.

Mr. Ostrander, who retired in 1975, had participated in pioneer investigations of cosmic rays in the upper atmosphere.

In 1946, he joined a newly formed group at the laboratory doing high altitude research and headed by Dr. James A. Van Allen, discoverer of the Van Allen radiation belts around the earth.

He went with the Van Allen research team to White Sands Proving Ground in New Mexico, where captured German V-2 rockets and Aerobee sounding rockets were fired to altitudes of over 100 miles to gather data on cosmic rays. He was a member of the instrumentation team that prepared, tested and installed cosmic ray detection equipment in the noses of high altitude rockets and later in high altitude balloons.

Mr. Ostrander went to Greenland in 1950 with a cosmic ray study expedition. It instrumented balloons that tracked altitudes to 130,000 feet, providing basic data on the prevalence of cosmic rays in the Arctic zones. He also was a member of laboratory teams that developed guided missile defenses for the U.S. fleet.

He was born in Cleveland and earned a degree in electrical engineering from Case Institute of Technology there. He then taught at Case and at Fenn College in Cleveland. He was a transmitter engineer with the United Broadcasting Co. in Cleveland from 1930 to 1942

Mr. Ostrander was a member of York Masonic Lodge No. 225 in Cheverly and a past patron of Chevely chapter No. 111 of the Eastern Star.

He is survived by his wife, Elizabeth E., of the home in Silver Spring, and a son, Eugene W. of Laurel.