It is two months since I previewed the imminent launch of the shuttle Discovery on its final mission to the International Space Station. Problems since then, initially due to a fuel leak and then to cracks in the foam insulation and structure of the external tank, have delayed the launch to 3 February, with the chance that even this date might slip after another four cracks were found over Christmas.

Meanwhile, the ISS is once more making conspicuous eastwards transits across our evening sky, with the one of its best this evening when it sails directly over S England at 17:27. Asterisks in our predictions flag the directions in which it fades from sight as it enters the Earth's shadow.