Image: NASA |
Since its launch almost three years ago on October 15, 1997, the Cassini spacecraft has returned a stream of information on the planets it has passed en route to Saturn. On April 26, 1998, and June 24, 1999, it swooped past Venus; on August 18, 1999, Cassini took its controversial cruise 1,170 kilometers over Earth. And now the craft is closing in on Jupiter, where it will capture a series of images in the coming months. Cassini's flybys of the other planets uses their gravity like a slingshot, helping to hurl the two-story-tall probe toward its final destination for a scheduled arrival on July 1, 2004.
Cassini's first color image of Jupiter, shown here, was taken from a distance of about 81 million kilometers. The characteristic colored latitudinal bands in the giant planet's upper atmosphere are clearly visible¿as is a shadow cast by Europa, one of Jupiter's largest moons. Similarly stunning black-and-white pictureswere snapped earlier this week from a greater distance. "The spacecraft is steadier than any spacecraft I've ever seen," commented Carolyn Porco of the University of Arizona, team leader for the camera. "It's so steady, the images are unexpectedly sharp and clear, even in the longest exposures taken and most challenging spectral regions." The pictures should get even sharper as Cassini continues to approach Jupiter, reaching its closest point on December 30, 2000.
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The success of Cassini's camera is especially good news to scientists at NASA, the European Space Agency (ESA) and the Italian Space Agency¿collaborators on the mission¿because it comes soon after they found a problem with one of the spacecraft's communications systems. The plan is that, on arrival at Saturn, ESA's Huygens probe, now attached to Cassini, will separate and travel down to the moon Titan. But tests in September showed that the radio receiver on board Cassini might not be able to collect all the data Huygens sends back. Fortunately, Huygens won't go its own way for at least another four years, and Cassini's team should be able to work out an alternative solution by then.
