Cassini's Magnificent Machines Run Rings Around Saturn

摘要

Cassini's arrival at Saturn last week was a dream come true. The spacecraft's 5.7 tons of technology performed flawlessly, promising beleaguered NASA and its European partners years of positive public interest. And now that Cassini is safely into Saturn orbit, researchers can look forward to years of daily gigabit science returns from a planetary system that in many ways evokes the early days of our solar system (Science, 28 May, p. 1230). The first data dumps show that Cassini's 12 sophisticated instruments should deliver on the $3.3 billion investment. Cassini's images of Saturn's rings contained suph exquisite detail that even the camera's principal investigator (PI) ― Carolyn Porco of the Space Science Institute in Boulder, Colorado― was flabbergasted, despite her 15 years. of planning for the latest "Oh my god, look at that!" she exclaimed on seeing phonograph-like "grooves" in Saturn's A ring, the outermost of the three main rings. This so-called spiral density wave and others like it had been discovered by the two Voyager spacecraft that flew by Saturn in 1980 and 1981, but the new images benefit from a more massive camera, 20 years of electronic technology development, and a far steadier spacecraft. "That's gorgeous, just gorgeous," said Porco. "These density waves are like books, just waiting to be read."