Exactly 40 years ago, Apollo 10 blasted off Earth; its mission in the words of Commander Tom Stafford "to sort out the unknowns and pave the way for a lunar landing". Continuing his series of essays marking the 40th anniversary of the moonshots, Dr Christopher Riley reflects on Nasa's method for landing on the Moon and the Apollo legacy of space rendezvous.
More: http://news.bbc.co.uk/2/hi/science/nature/8056443.stm