In a space-age game of chicken, the European Space Agency's (ESA) Rosetta probe made its closest approach to comet 67P/Churyumov–Gerasimenko last weekend. The spacecraft, which has ceased orbiting the comet due to 67P's increased activity as it approaches the Sun, came within 6 km (3.7 mi) of the surface over the Imhotep region of the larger of the comet’s two lobes, with the up close and personal maneuver taking place, appropriately enough, on Valentine's Day.
The flyby took place at 12:41 GMT on February 14, and as Rosetta carried out the maneuver it returned a series of images of the comet's layered and fractured surface. The images revealed a complicated, broken landscape mixed with smooth, dust-covered areas, boulders measuring up to tens of meters, and outlines of near-circular objects about which little is clearly understood. In addition, the close pass allowed the spacecraft's instruments to take samples of the inner regions of 67P's coma.
Rosetta has been studying 67P since it first went into orbit around the comet in August of last year. For much of that time, it was mapping the surface in anticipation of the Philae probe making the first soft landing on a comet in history. Since then, the spacecraft has been making a detailed study of the comet and its coma in hopes of gaining a better understanding of the mechanisms that shape comets as they approach the Sun.
According to ESA, Rosetta is about 345 million km (214 million mi) from the Sun. When 67P reaches its closest distance to the Sun on August 13, it will be 189 million km (117 million mi) away between the orbits of Earth and Mars. Because 67P is becoming more active as the Sun heats it, Rosetta has gone out of orbit and is now executing a series of flybys at altitudes from 15 to 100 km (9.3 to 62 mi).
The video below discusses the Valentine's Day flyby.