▁ 1 7 ▁May ▁ 1 9 6 9 . ▁F lying ▁for ▁six ▁and ▁a ▁half ▁hours ▁at ▁low ▁alt itude ▁in ▁the ▁dark , ▁they ▁arrived ▁over ▁the ▁target ▁and ▁the ▁sensor ▁pal lets ▁were ▁dropped ▁by ▁par ach ute ▁near ▁An xi ▁in ▁G ans u ▁province . ▁After ▁another ▁six ▁and ▁a ▁half ▁hours ▁of ▁low ▁alt itude ▁flight , ▁they ▁arrived ▁back ▁at ▁Tak h li . ▁The ▁sens ors ▁worked ▁and ▁uploaded ▁data ▁to ▁a ▁U . S . ▁intelligence ▁satellite ▁for ▁six ▁months ▁before ▁their ▁batter ies ▁failed . ▁The ▁Chinese ▁conducted ▁two ▁nuclear ▁tests , ▁on ▁ 2 2 ▁September ▁ 1 9 6 9 ▁and ▁ 2 9 ▁September ▁ 1 9 6 9 , ▁during ▁the ▁operating ▁life ▁of ▁the ▁sensor ▁pal lets . ▁Another ▁mission ▁to ▁the ▁area ▁was ▁planned ▁as ▁Operation ▁Golden ▁Wh ip , ▁but ▁was ▁called ▁off ▁in ▁ 1 9 7 0 . ▁It ▁is ▁most ▁likely ▁that ▁the ▁aircraft ▁used ▁on ▁this ▁mission ▁was ▁either ▁C - 1 3 0 E ▁serial ▁number ▁ 6 4 - 0 5 0 6 ▁or ▁ 6 4 - 0 5 0 7 ▁( cn ▁ 3 8 2 - 3 9 9 0 ▁and ▁ 3 8 2 - 3 9 9 1 ). ▁These ▁two ▁aircraft ▁were ▁delivered ▁to ▁Air ▁America ▁in ▁ 1 9 6 4 . ▁After ▁being ▁returned ▁to ▁the ▁U . S . ▁Air ▁Force ▁som etime ▁between ▁ 1 9 6 6 ▁and