Maybe they read the myriad of old articles about the site? http://www.popsci.com/why-soviet-space-shuttle-was-left-rot http://www.popsci.com/why-soviet-space-s

Maybe they read the myriad of old articles about the site? http://www.popsci.com/why-soviet-space-shuttle-was-left-rot http://www.popsci.com/why-soviet-space-shuttle-was-left-rot The above is from 2015, though I recall reading about the find years earlier.