The complex is on a military base controlled by Iran, making access difficult. But through information from satellite tv direct imagery, Iranian dissidents and other human intelligence, a sufficiently detailed picture was built up to convince investigators that Iran was preparing to make nuclear fuel there.
To view original article and images of construction site, please visit herehttp://news.satimagingcorp.com/2009/11/satellite tv direct_imagery_reveals_arak_irans_nuclear_site_construction.html