 Three more Canyons were launched in 1972, 1975, and 1977, all of which performed well and gathered considerable intelligence on Soviet activities as well as Arab communications during the 1973 Yom Kippur War.Indeed, the amount of communications data returned was so voluminous that some of it took up to two years to sort through.The Air Force did not acknowledge the existence of the program at all until 1990, thirteen years after the last Canyon was launched.