After a journey that has lasted a decade, Europe’s Rosetta spacecraft is now on its final approach to a comet. The tiny probe is set to rendezvous on Wednesday with one of the strangest objects in the solar system. The latest in a series of manoeuvres will bring Rosetta to within 100km of Comet 67P.
Throughout human history, comets lighting up the night sky have triggered fascination and fear but their speed and distance have made them difficult to investigate. One theory is that they delivered water, carbon and other essential building-blocks for life to the early Earth. Previous missions have had to be fly-bys – brief encounters crossing a comet’s path to gather data or collect samples of dust.
By contrast, Rosetta is designed to fly around comet 67P in a form of orbit for more than a year, its 11 instruments providing unprecedented information about the comet’s structure and composition. If all goes according to plan by November, mission managers will pick a spot for what will be an audacious attempt to send a lander, known as Philae, to touch down. For the moment though, all eyes will be on Wednesday’s landmark manoeuvre which should bring Rosetta into a controlled flight in a triangular pattern around the comet.