FreeLook BookStore

Flying From the Sun on Gossamer Wings

        (From a JPL-NASA press release 03 Jul 2002) The Rosetta spacecraft spread its wings like a solar-powered butterfly as engineers at the European Space Research and Technology Centre in the Netherlands put it through its paces. Delicate preflight tests checked various arrays and booms that will be extended from the cube-shaped body of the Rosetta orbiter during its eight-year trek for a look at Comet Wirtanen.
        Two giant solar wings will power Rosetta throughout a 10-year
mission to deep space and back. These wings, each of which spreads 14 meters (roughly 14 yards!) spread, are covered with more than 22,000 specially developed silicon cells that will continue to operate in the deep cold of deep space and draw power from the tiny amounts of sunlight that reach five times the Earth's distance from the Sun.
        Rosetta stretched first one wing — the 'minus-y' array, located to the left of the dish-shaped high gain antenna, — then the other, the 'plus-y' array on the opposite side of the spacecraft. At a command from the space craft, the six Kevlar cables that keep the wings folded during launch were cut, one after the other, by "thermal knives" were cut by heating them to a temperature of several hundreds of degrees Celsius. When the sixth cable was severed, the array began to unfold until the five panels in each array gradually extended to full length across the clean room where the test took place. The weight of the arrays was supported by a mass compensation device equipped with dozens of springs that simulate the zero gravity conditions of outer space. Tests went very well and there was a big round of applause when they were completed.
        What's next? More planning and more tests are underway as the launch program moves forward. Rosetta expects to stretch her solar wings in earnest in about six months' time.