FORTUNE's annual ranking of America's leading businesswomen

31 of 50
31. Joanne Maguire
Joanne Maguire
EVP, Space systems
Lockheed Martin
2011 rank: 29
Age: 58
Sales in Maguire's division fell as Lockheed completed its work on the final space shuttle mission last year, but an influx of missile and satellite orders curbed the decline. Maguire increased operating margins in her $8 billion business, which accounts for 18% of Lockheed's total revenue.
From the October 8, 2012 issue
How we pick the Power 50
The list is compiled by FORTUNE editors, who consider four criteria: the size and importance of the woman's business in the global economy, the health and direction of the business, the arc of the woman's career (resume and runway ahead), and societal and cultural influence.