Yeager went on to break many other speed and altitude records. He was also one of the first American pilots to fly a Mikoyan-Gurevich MiG-15, after its pilot, No Kum-sok, defected to South Korea. Returning to Muroc, during the latter half of 1953, Yeager was involved with the USAF team that was working on the X-1A, an aircraft designed to surpass Mach 2 in level flight. That year, he flew a chase aircraft for the civilian pilot Jackie Cochran as she became the first woman to fly faster than sound.