U.S. Air Force Staff Sgt. Lukus Pence, 732d Air Mobility Squadron air freight operations supervisor, tightens a cargo strap on a pallet full of aircraft fire extinguishers during Polar Force 19-4 at Joint Base Elmendorf-Richardson, Alaska, March 24, 2019. Polar Force is a two-week exercise designed to test JBER’s mission readiness. Exercises like this strengthen and develop the skills service members require when facing adverse situations.