Kranz continued as a Flight Director through Apollo 17, when he worked his last shift as a flight director overseeing the mission liftoff, and then was promoted to Deputy Director of NASA Mission Operations in 1974, becoming Director in 1983. He was in Mission Control during the January 28, 1986, loss of Space Shuttle "Challenger" on the STS-51-L launch. He retired from NASA in 1994 after the successful STS-61 flight that repaired the optically flawed Hubble Space Telescope in 1993.