THE TENSION: Combat Camera: Defend America for 31 Jan. 2007

A KC-135 Stratotanker from Grand Forks Air Force Base N.D., refuels an F-22 Raptor from Edwards AFB, Calif. Jan. 18. A refueling team from Grand Forks will be the lead tanker unit at an upcoming Red Flag exercise. (U.S. Air Force photo/Darin Russell)

Four "golf ball" protective covers at Thule Air Base, Greenland that house satellite dishes glow during the darkness Jan. 25. Thule AB Airmen use the satellite dishes to communicate with orbiting satellites. (U.S. Air Force photo/Michael Tolzmann)

Senior Airman Mathew Steer and Senior Airman Richard Rodriguez monitor vehicles closely Jan. 24 at an entry control point at Kirkuk Regional Air Base, Iraq. Both are Kirkuk Air Base perimeter guards for the 506th Expeditionary Security Forces Squadron. (U.S. Air Force photo/Senior Airman Bradley A. Lail)

Pilots from the 354th Fighter Squadron taxi in their A-10 Thunderbolt II aircraft to the runway Jan. 21 as they prepare to takeoff for a simulated deployed location during a training exercise at Davis Monthan Air Force Base, Ariz. (U.S. Air Force photo/Senior Airman Jesse Shipps)

A C-17 Globemaster III prepares to take off Jan. 17 from an undisclosed location in Southwest Asia. (U.S. Air Force photo/Staff Sgt. Edward D. Holzapfel)

Staff Sgt. Justin Mcnichols' checks one of the engines of a B-52 Stratofortress Jan. 19 at Minot Air Force Base, N.D. The engines are being tested to measure the difference between using traditional JP-8 fuel verses a synthetic fuel. The bomber is being used to test alternative fuels. (U.S. Air Force photo/Airman 1st Class Joe Rivera)