"But in reality, Mars' surface looks more similar to a desert on Earth." Mr Waring went on to accuse NASA of doctoring its images to obscure the supposed fact Mars is

hospitable. He said: "This way, there is no other country racing to Mars and NASA will have no competition... which gives them a lot of time to get there." But the Red Planet is

very much the opposite of being hospitable, with no vegetation, a paper-thin atmosphere and planet-sized dust storms. There are also many reasons why the US space agency alters the colours

of its rover photos, none of which have to do with aliens.