Rosetta has finally met its cometary match. Last week, after a 10-year journey, the European Space Agency's spacecraft arrived at comet 67P/Churyumov-Gerasimenko, a lopsided, bilobed lump of dust and ice sometimes likened to a 4-kilometer-long rubber duckie. The duo will now take a lap around the sun, and Rosetta will watch as the comet heats up and releases ice in a halo of gas and dust (Science, 1 August, p. 502). The spacecraft is now flying triangles in front of the comet, staying 100 kilometers away; in several weeks, Rosetta will settle into a 30-kilometer orbit around the comet. Mission scientists are gearing up to map the comet's surface in hopes of finding a smooth area on which to drop Philae, a lander the size of a washing machine, this November. To help it stick the landing in the comet's feeble gravity field, Philae will use two harpoons. Then, it will drill into the comet to gather surface material for analysis.
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