orts -- the phrase ‘space tourism’ should be avoided. It lulls people into unrealistic confidence. By 2100 courageous pioneers in the mould of (say) Felix Baumgartner, who broke the sound barrier in free fall from a high-altitude balloon -- may have established ‘bases’ independent from the Earth — on Mars, or maybe

this world: man-made laws that we shouldn't break, like the speed limit, and natural laws that we can't break, like gravity. Austrian dare- devil Felix Baumgartner recently illustrated the latter when he jumped from a capsule 39km above the earth, becoming the first skydiver to break the sound barrier with n