USAF Air Defense Command radar station 865th ACWRON, Las Vegas AFS, Angel Peak (36°19.1'N, 115°34.4'W), Nevada, Senior Director First Lieutenant Clifford E. Pocock, scope operator A/2c Walter Lyons, and control technician A/lc Armand Therrien, using the FPS-3A L-band search radar tracked an inbound target at average speed of about 6,200 mph for 48 seconds (?) when it "stopped abruptly" and "remained stationary" for 12 seconds to the ENE at 75° azimuth 85 miles range, north of Grand Canyon, then target headed outbound at about 7,000 mph on 85° heading over the last 72 seconds before disappearing at the radar's maximum range at 81° azimuth 224 miles range (near Marble Canyon, Ariz.). Target responded to encrypted military IFF transponder signals and transmitted encrypted responses. Similar occurrence two days earlier noted by night crew but none others in two years.

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