In 1956 the London Evening Standard commissioned Arthur C. Clarke to write a series of short stories about an international mission to the Moon, collected afterwards in his anthology “The Other Side of the Sky” and reprinted in “Arthur C. Clarke, The Collected Stories” (Gollancz, 2000). The participants were the British, the Americans and the Russians. In a story called ‘Watch This Space’, towards the end of their stay the Americans are to recapitulate an experiment conducted by sounding rocket from White Sands in 1955, releasing a cloud of sodium vapour to fluoresce in sunlight at high altitude. It’s to be done from the Moon on a scale to be visible from Earth…

“… a sudden yellow glow began to spread across the sky, like a vast and unwavering aurora that became brighter even as we watched. It was as if an artist was sprawling strokes across the stars with a flame-filled brush. And as I stared at those strokes, I suddenly realised that someone had brought off the greatest advertising coup in history. For the strokes formed letters, and the letters formed two words – the name of a certain soft drink too well-known to need any further publicity from me.

“How had it been done? The answer was obvious. Someone had placed a suitably cut stencil in the nozzle of the sodium bomb, so that the stream of expanding vapour had shaped itself to the words. Since there was nothing to distort it, the pattern had kept its shape during its invisible ascent to the stars. I had seen skywriting on Earth, but this was something on a far larger scale. Whatever I thought of them, I couldn’t help admiring the ingenuity of the men who had perpetrated the scheme. The O’s and A’s had given them some trouble, but the C’s and L’s were perfect.”

Actually there’s only one L, but there’s no need to be pernickety. Like Sydney with his prediction of the Moon landing date, once again as so often, Arthur was ahead of the game.