Blew moon – but it didn't even flinch

Published on Friday 9 October 2009 22:09

A MISSION to send two spacecraft smashing into the moon and blow up part of its surface ended with a whimper not a bang yesterday – but was still hailed a triumph.

The "bombing" of the moon was supposed to kick up a six-mile-high cloud of debris big enough to be seen by amateur astronomers on earth.

But live pictures relayed back showed no obvious sign of an impact – even though both craft dived into a darkened crater as planned.

The plan was to scan the plume for evidence of water, believed to lie at the bottom of freezing polar craters.

A British scientist who helped the US space agency Nasa pick the impact spot near the lunar south pole was puzzled after viewing the images.

"If it turns out to be as dull as it looked, I'd imagine the soil just didn't respond to being hit as was hoped," said Dr Vincent Eke, of Durham University. "It might mean we don't get sufficient data, which would be a shame."

But Nasa insisted the mission had gone according to plan, suggesting that public expectations based on pre-crash animations might have been too high.

Doug Cooke, of the Exploration Systems Mission Directorate at Nasa HQ in Washington, said: "This is a great day for science and exploration."

The crashing craft consisted of a moon-mapping orbiter, LCROSS (Lunar Crater Observation and Sensing Satellite) and the 2.2-tonne empty upper stage of a Centaur rocket that helped launch it into space.

After separating, the rocket hull was first sent hurtling towards the crater Cabeus at more than 5,000 mph.

It hit the surface with a force said to be equivalent to 1.52 tonnes of TNT, enough to blow a hole half the size of an Olympic pool.

The LCROSS probe was to beam pictures back to Earth as it flew through the dust cloud thrown up by the blast, and take readings for evidence of water.

Four minutes after the first impact, the satellite took the plunge itself, striking the crater with a third less energy. But the Nasa broadcast of the event proved an anticlimax.

No hint of the promised dramatic explosion was seen, and released Nasa photos showed little more than a fuzzy white flash.

The agency said the lighting was bad and work was needed to enhance the "grey against black" images. It also claimed animations of the expected event might have been unrealistic. But the agency said all the probe's five cameras and other instruments had worked perfectly and "received good data".

Information had also been obtained by ground telescopes which would now be carefully analysed.

It could take two weeks before the scientists, looking for chemical signatures in sunlight reflected off the dust particles, can say with confidence whether or not they have found water.

"What matters for us is: what is the nature of the stuff that was kicked up going in," said project manager Dan Andrews.

Water on the moon could be vital to future missions to build lunar bases or send astronauts to Mars from a lunar staging post.

Moon water could be used both for drinking and the production of fuel and oxygen.

Dr Eke led a team of scientists who analysed data from Nasa's 1998 Lunar Prospector mission. They found evidence of high concentrations of hydrogen – a key component of water – within permanently shadowed craters at the moon's north and south poles.