Site 43, also known as SK-3 and SK-4, is a launch complex at the Plesetsk Cosmodrome in Russia. It consists of a two pads, Sites 43/3 and 43/4, and has been used by R-7 derived rockets since the early 1960s.The site was originally built for use by R-7A Semyorka missiles. The first launch to use the complex was an R-7A test on 21 December 1965, from Site 43/3. The first launch from 43/4 followed on 25 July 1967.