And then the last decade was about detailed design, securing the sites, getting governments to agree to set up a treaty organisation (SKAO) and provide the funds to start," he told BBC News.To expand these sites, however, has required various land agreements, with farmers in the Karoo; and with the Wajarri Yamaji, the Aboriginal title holders in the Murchison.These will take the total financial outlay to date to just under €500m (£430m) - out of an expected final construction budget of €2bn.The first major milestone should come in 2024, when four dishes in Australia and six antenna stations in South Africa are made to work seamlessly together as a basic telescope."And we're actually in the process of talking to other countries as well, to see what interest they might have in joining the observatory," said Prof Diamond."