At Vanderbilt University Chappell is a Research Professor of Physics and a Consulting Space Scientist in Public Affairs involved in teaching, research, and science communication. He was the Executive Director of the Vanderbilt Dyer Observatory from 2002-2009. Chappell graduated magna cum laude in physics from Vanderbilt and received a Ph.D. degree in space science from Rice University. He has authored numerous published scientific articles regarding the Earth's space plasma environment and has testified before Congress on the importance of communicating science to the public. Before returning to Vanderbilt in 1996, he served as the Chief Scientist at NASA's Marshall Space Flight Center in Huntsville, Alabama. From 1976 to 1985, Chappell was the mission scientist for Spacelab 1, a joint European/American shuttle mission. In December 1985, he was selected to train as an alternate payload specialist for the space shuttle mission STS-45, which was carried out in March 1992. As a scientist and spokesman for the space program, Chappell has been interviewed on NBC's Today Show, ABC's Nightline and the BBC and has provided color commentary on CNN for space shuttle missions. Chappell is a member of Phi Beta Kappa and has twice received the NASA Medal for Exceptional Scientific Achievement. At his retirement from NASA In 1997 he was presented the NASA Medal for Exceptional Scientific Achievement.