What cabinet position had been held by the head of the commission that investigated the STS-51L disaster?

Secretary of State

Ronald Wilson Reagan February 6, 1911 – June 5, 2004 was an American politician and actor who was the 40th President of the United States, from 1981 to 1989. Before his presidency, he was the 33rd Governor of California, from 1967 to 1975, after a career as a Hollywood actor and union leader.

The Secretary of State is a senior official of the federal government of the United States of America heading the U.S. Department of State, principally concerned with foreign policy and is considered to be the U.S. government’s equivalent of a Minister for Foreign Affairs.