THANK YOU Defense Secretary Leon E. Panetta congratulates Navy Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, at the conclusion of what was Mullen'ss last appearance before the Senate Armed Services Committee, Sept. 22, 2011. Mullen will retire after more than 40 years of military service, Sept. 30, 2011. SHARE: Download: Full Size (0.06 MB) Credit: VIRIN: 972090-Z-QQC59-675.jpg Photo Gallery