Nuclear batteries that would have kept running irrespective of where the probe landed on the comet were rejected for political reasons, a senior scientist involved in the mission has said.

Junior fellows often work closely with a senior scientist, while advanced fellows pursue their own research.

He became staff senior scientist in 1989 and served in this role until 1995.

In 1987, he became a senior scientist studying the crystalline structure and mechanical properties of solids.

He was senior scientist of natural history for the society from 1958 to 1975.