Since then, the complex has helped launch a total of 325 rockets, beginning with the 1957 launches of PGM-17 Thor—America's first operational ballistic missile.
The towers were retired in 2009 and 2011 respectively, and their destruction has been planned by the US Air Force for years. The $2 million demolition was successfully triggered at 7AM ET by brigadier general Wayne Monteith, commander of the Air Force's 45th Space Wing. Once it's cleaned up and refurbished, the site will be leased by Moon Express, a private company that is developing lunar landers for commercial use.
SLC-17 was a key location not only in spaceflight history, but for the rollout of modern conveniences like cell phones and navigation aids. It is famous for sending Echo 1, the first communications satellite, into orbit in 1960, and for launching Telstar-1, a satellite that produced the first live television feeds between Europe and the United States, in 1962. It has also blasted several satellites into space to join the Global Positioning System (GPS) constellation.
SLC-17 was also the birthplace of the Delta rocket family, one of the most commonly used and versatile launch vehicle groups. The Mars Exploration Rovers, Opportunity and Spirit, were blasted off to the red planet from this spot, as was the Phoenix Mars lander. The pad sent the MESSENGER mission to Mercury, the Dawn spacecraft to Vesta and Ceres, and NASA's prolific Spitzer and Kepler space telescopes into their orbits around the Sun.