This monitoring activity was directly related to Kennedy's LTBT safeguards: to monitor testing by other nations. An ongoing assignment of the 58th Weather Reconnaissance Squadron was observation for evidence of Soviet Union and Communist Chinese nuclear tests, a direct response to Safeguard D. For example, the 58th Weather Reconnaissance Squadron flew back and forth to Argentina during 1965 for its top secret "Quick Dip" program. Quick Dip involved biweekly flights of two RB-57Fs to El Plumerillo Airport in Mendoza, Argentina, for periods of four to five days. During each period, five to six air samplings were to be taken to estimate the amount of plutonium being produced by the Soviets.