Air conditioning eventually reach the upper atmosphere. Once the refrigerant reaches the stratosphere, UV radiation from the Sun homolytically cleaves the chlorine-carbon bond, yielding a chlorine radical. These chlorine radicals catalyze the breakdown of ozone into diatomic oxygen, depleting the ozone layer that shields the Earth's surface from strong UV radiation. Each chlorine radical remains active as a catalyst until it binds with another radical, forming a stable molecule and quenching the chain reaction. Prior to 1994, most automotive air conditioning systems used R-12 as a refrigerant. It was replaced with R-134a refrigerant, which has no ozone depletion potential. Old R-12 systems
S-1 (satellite) 4". "S-1" was the first geocentric orbit launch attempt for the rocket; its second attempt on August 14, 1959, carrying the "Beacon 2" inflatable sphere experiment to low Earth orbit, also failed. Eventually, both the Juno II and a re-launch of the "S-1" mission, designated "Explorer 7" or "S-1A", found success on October 13, 1959. The satellite, which ended its mission in August 1961, is still orbiting the Earth today. S-1 (satellite) S-1, also known as Explorer S-1 and Explorer 7X, was a geoscience satellite equipped with a suite of scientific instruments to study the environment around the Earth. The