Eight persons including a Baltimore contractor and five members of his family were found dead yesterday after an experimental Soviet satellite picked up an emergency signal from the wreckage of their plane that crashed in the foothills of the Blue Ridge mountains near Martinsville, Va.

The twin-engine Piper Navajo crashed about 7:30 p.m. Sunday about 1,500 feet off the runway at Blue Ridge Airport near the North Carolina line.

Radio signals from the plane's emergency locator transmitter were picked up by the Soviet satellite and, under international agreement, transmitted automatically to Air Force search and rescue headquarters at Scott Air Force Base in Illinois, according to a National Aeronautics and Space Administration official.

The signal from the satellite, still in its "checkout phase," has been used at least once before to locate wreckage of a crashed plane within the United States, according to Bernie Trudell, mission manager for the search and rescue program at Goddard Space Flight Center.

According to a Federal Aviation Administration spokesman, the Navajo hit something, possibly a tree, after taking off in darkness and light rain. It came down in a heavily wooded area.

The dead included John E. Steigerwald Jr., president of J.E. Steigerwald Co. Inc., whose body was found in the pilot's seat; his wife Lois, and his daughters Pamela Fromm and Amy. Also killed were Pamela's husband, Tim, their 3-year-old child, Tim, and two friends of Amy's, Renita Copeland and Susan Goshorn, both Johns Hopkins University students.

Authorities said they were uncertain of the plane's destination.

According to one account, the plane was spotted both by searchers alerted by the satellite signal and by a pilot independently using the airport.