|18th United States Secretary of the Air Force|
August 6, 1993 – October 31, 1997
|Preceded by||Donald B. Rice|
|Succeeded by||F. Whitten Peters|
Sheila Marie Evans
July 13, 1938
Tacoma, Washington, U. S.
|Education||Massachusetts Institute of Technology (SB, SM, ScD)|
Sheila Marie Evans Widnall (born July 13, 1938) is an American aerospace researcher and Institute Professor Emerita at the Massachusetts Institute of Technology (MIT). She served as United States Secretary of the Air Force from 1993 to 1997, making her the first woman to hold that post and the first woman to lead an entire branch of the United States Armed Forces in the Department of Defense. She was inducted into the National Women's Hall of Fame in 2003.
Widnall was born and raised in Tacoma, Washington, graduating from the Aquinas Academy for Girls in 1956. She graduated from MIT with a SB in 1960, SM in 1961, and ScD in 1964, all in Aeronautics. Her master's thesis was entitled Boundary layer stability over flexible surfaces and her doctoral thesis was entitled Unsteady loads on hydrofoils including free surface effects and cavitation, both under the supervision of Marten T. Landahl.
Widnall was appointed as the Abby Rockefeller Mauzé Professor of Aeronautics and Astronautics in 1986 and joined the Engineering Systems Division, was Chair of the Faculty 1979–1981, and has served as MIT's Associate Provost from 1992–1993. In 1988 she was the President of the American Association for the Advancement of Science. She was elected to the American Academy of Arts and Sciences that same year. In 2000, Widnall was elected to the American Philosophical Society.
On July 4, 1993, in the wake of the Tailhook scandal, President Bill Clinton announced her nomination to be Secretary of the Air Force. The Senate received her nomination July 22, 1993, and confirmed her two weeks later on August 5, 1993, 183 days after inauguration and 197 after the office became vacant. She was the first woman to head a branch of the US military. During her tenure she handled the Kelly Flinn scandal. She was elected to the National Academy of Engineering in 1985, serving as vice-president from 1998 to 2005 and winning their Arthur M. Bueche Award in 2009.
Widnall was a member of the board of investigation into the Space Shuttle Columbia disaster.
She currently works with the Lean Advancement Initiative. She married William Soule Widnall in June 1960. Her husband earned a doctorate degree from MIT in aerospace engineering and headed the MIT-Draper team that developed the Apollo GN&C system. The couple has two grown children, William and Ann Marie.
Widnall's research has been focused on fluid mechanics, in particular the aerodynamics of high-speed vehicles, helicopters, aircraft wakes, and turbulence. One of her most notable works is on the elliptical instability mechanism with Raymond Pierrehumbert.
Even as she asked in vain for an honorable discharge, First Lieut. Kelly J. Flinn said in a letter to the Secretary of the Air Force that having to leave the service was a punishment she would carry to her grave.