It is either said "Polaris", "Pol'laris", "pol'ar'iz", "Pola'ris", "Pol'arris" or "Pol'aris". I remember from the early 1980s, shortly after the Falklands War was over, reading a report in at tabloid newspaper of the time (I think it was the Mirror) of the confusion over the exact naming of the UGM-27 Polaris missiles stationed in the UK started after some civil servants had got confused over the American and UK pronunciation of the word that was the missiles name was. It was caused in the early 1980s when it was thought they were 2 related, but different rockets in each country, when really it was just the same name said differently.