Sir

Your News story “Europe's Mars mission to pay out for Beagle lander” (Nature 414, 679; 2001) reported that the European Space Agency (ESA) “has been forced to allocate 36 million euros” (US$32 million) to the UK-led Beagle 2 lander. This is misleading.

ESA's Science Programme Committee agreed on 4–5 December 2001 an increase (actually of 35.4 million euros) in the cost to completion of Mars Express, the spacecraft that will carry Beagle 2 to Mars but which will itself carry out a major survey of the planet. The only new resource directly attributable to Beagle 2 is the aseptic assembly facility, which is required to meet planetary-protection requirements and was approved at a cost of 3 million euros.

Of course, the overall technical development, integration and testing for Mars Express and Beagle 2 are closely linked; Beagle 2 is not simply added to the payload at the launch site. Accordingly, ESA is monitoring carefully the development of Beagle 2 as its schedule needs to dovetail smoothly with Mars Express.