Even something as exhaustively planned as the test-flight of the Orion spacecraft
isn't immune to a slipping timeline. It's reportedly been pushed back from next year to 2014 -- when we're expecting to see the capsule launch from Cape Canaveral, loop around the planet twice at 3,700 miles (the furthest any spacecraft has journeyed since the '70s) before splashing down in the Pacific. This unmanned test was designed to see if the vehicle's heat-shield, flight-software and parachutes all work before lives are risked on board. It's also signified a pushing back of the first launch from 2016 until 2021. This means there's nine more years before someone calls us up as a crew replacement
-- at least that's how our dream goes.