US tycoon and first space tourist Dennis Tito has revealed plans to send a couple on a 501-day journey for a flyby mission to Mars in 2018 in an attempt to inspire future generations and revitalise American science. Tito said on Wednesday it was important that the mission take place in 2018 because the planets will be closest in their orbital paths. If the opportunity is missed the next chance would be in 2031. Tito sees the privately funded mission called Inspiration Mars Foundation as a great American undertaking, but he avoided giving any details about the expenses involved and where the money would come form. Al Jazeera's John Terrett reports from Washington DC.