A spacecraft that launched the first war of the worlds is being sent to track down a new target. The Deep Impact probe fired an 820lb smart bomb at a distant comet called Tempel 1, exactly two years ago today.

It blasted a huge crater out of the comet’s head with the force of 4.5 tons of TNT. The brilliant flare was clearly visible 83 millions miles away back on Earth.

Now Nasa has approved plans to send Deep Impact to another comet called Boethin but this time it will just study it without any of the fireworks.

Boethin is a short-period comet that regularly returns to the inner solar system from beyond the orbit of Jupiter. Deep Impact is expected to fly past it on December 5, next year on a new mission dubbed Epoxi.

Deep Impact has been given a second objective – to try to find out more about alien planets in other solar systems. It will turn its sensitive camera on several nearby bright stars which are already known to have giant planets.

It will monitor the starlight as the planets pass in front of and behind their parent suns, collecting data which will be used to check whether they have rings, moons or Earth-sized companions.

Nasa Chief Scientist John Mather said: “Epoxi is a wonderful opportunity to add to our growing body of knowledge of exoplanets. Watching planets go behind or in front of their parent stars can tell us about their atmospheric chemistry.”

We are also set to learn more about Deep Impact’s original target because Nasa has agreed to extend a second probe’s mission in order to study it. Stardust, which collected and sent home particles from another comet called Wild 2, will now chase Tempel 1, flying past it on February 14, 2011.

Scientists want to examine the comet’s icy surface and check what damage was done by Deep Impact’s fridge-sized missile – the original blast was so bright that they did not get a proper look into the crater.

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