A NASA spacecraft is homing in today to check up on a comet that another probe blasted with a missile. Space scientists want to see how the cosmic iceball, called Tempel 1, had changed since the spectacular attack.
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In the earlier encounter in 2005, a craft called Deep Impact fired an 820 lb projectile into the comet’s heart.
The resulting explosion, with the force of 4.5 tons of TNT, was so bright and threw out so much dust that its cameras were unable to view the resulting crater, thought to be the size of a football stadium.
More than five years after the “war of the worlds” event, another probe called Stardust-NExT is due to fly to within 125 miles of Tempel 1 at 04.37 UT tomorrow.
There will be no repeat attack, but scientists hope to get good views of the damage they inflicted and discover, for example, whether the surface is hard or soft.
The comet has also completed one swoop past the sun since the last visit and NASA will check the effects that the fierce solar heat had on it.
NASA’s chief investigator on the project, Joe Veverka, said: “For the first time, we’ll see the same comet before and after its closest approach to the sun. Deep Impact gave us tantalizing glimpses of Temple 1. We saw strange and unusual things we’d like a closer look at.”
Stardust-NExT, which was launched in 1999, has already visited one comet, called Wild 2, in 2004. It collected samples of its dust which it jettisoned back to Earth in a canister in January 2006. Watch the NASA video about Stardust below.
Deep Impact flew on to visit another comet, called Hartley 2, in November last year, photographing jets of gas and dust spewing from the peanut-shaped head.
Astronomers are interested in comets because they are thought to have brought the basic seeds of life to our planet including the water in all our oceans.
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