Scientists will attempt to make history this week by landing a robotic probe on the surface of a comet more than 300 million miles away.
The spider-like probe will be released by the Rosetta spacecraft, currently orbiting comet 67P/Churyumov-Gerasimenko – a four-kilometre wide sooty lump of ice and dust – at around 8:35am UK time on Wednesday.
Seven hours later the probe, named Philae, is due to touch down on the comet’s rugged surface, anchoring itself in place with two harpoons and whirling ice screws attached to each of its three legs.
If all goes well, it will be the first time a man-made object has ever made a controlled landing on a comet. Nine years ago Nasa’s Deep Impact mission slammed a projectile into comet Tempel 1 to study debris from the blast. In contrast, European Space Agency’s (ESA) Philae will make a descent at walking pace.
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A radio message confirming the landing is due to reach scientists on Earth at around 4pm, having taken 30 minutes to travel 509 million kilometres (316 million miles) across space.
But there can be no guarantee that the mission, which scientists hope will provide valuable information about the origins of comets and the Solar System, will succeed.
Open University space scientist Professor Ian Wright, lead investigator for Ptolemy, a British-made box of electronics on Philae that will analyse material from the comet, said: “It’s a very risky undertaking. The Rosetta mission as a whole has already been successful, with or without the landing, but here is a chance to do something extremely challenging that has never been achieved before.
“We know the odds of success are not 100 per cent. There’s not a lot of gravity and you’ve got to stay connected to the surface, but we still don’t really know what it’s like. If the surface is too soft you run the risk of sinking down into it, and it it’s too hard you run the risk of bouncing off.”
Philae is covered in solar cells and is about the size of a dishwasher. It carries a suite of ten scientific instrument packages designed to measure virtually every characteristic of the comet, including its chemical composition, temperature and magnetic field. It is also equipped with several cameras that will take panoramic and close-up pictures of the comet.
Comets are thought to have carried both organic material and water to Earth, and may have been vital to the birth of life.
Rosetta, launched ten years ago, finally caught up with the fast-moving comet in August after an epic four billion mile journey that took it across the asteroid belt. It will travel with the comet as it flies past the Sun, approaching as close as 118 million miles.
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