US Air Force (USAF) STAFF Sergeant (SSGT) Sean Gunning (left) and USAF Technical Sergeant (TSGT) Timothy Winfree, both Security Police (SP) assigned to the 21st Space Wing (SW), Peterson Air Force Base (AFB), Colorado (CO), make their way over the "Easy Balancer" during the obstacle course event at Vandenberg Air Force Base (AFB) California (CA), during Exercise GUARDIAN CHALLENGE 2002. Guardian Challenge, a four-day space and missile competition, is hosted annually at Vandenberg AFB, CA to test the wartime readiness of Air Force Space Command (AFSPC) professionals