An element is a chemical substance made up of a particular kind of atom and hence cannot be broken down or transformed by a chemical reaction into a different element, though it can be transmuted into another element through a nuclear reaction.
Almost 40 years separate Shirley Ann Jackson's achievement, as the first African-American woman to earn a Ph.D. in theoretical high energy physics at Massachusetts Institute of Technology, and Jedidah Isler, the first African-American woman to receive a Ph.D. in Astrophysics from Yale.
Guion Bluford Jr. was the first black man and Mae Jemison the first black woman to travel in space (in 1983 and 1992, respectively). Bluford is an engineer and was a colonel in the United States Air Force before participating in four space shuttle flights.