Cassini's First Look at Jupiter
October 5, 2000

NASA scientists are extremely pleased with the first image of Jupiter, received yesterday, from the Cassini spacecraft, which is closing in on a fly-by of the huge planet. The image, first in a series of images and other measurements of Jupiter which Cassini will be making over the next several months as it flies by Jupiter, clearly shows the exceptional resolving power of the imaging system even at the distance of more than 52 million miles (84 million kilometers). Clouds, storms and latitudinal bands are clearly seen in the image. Color images will be processed in coming days. A steady stream of ever-closer color and black-and-white images will be released in the weeks ahead.

The new image of Jupiter is available from NASA's Jet Propulsion Laboratory at http://www.jpl.nasa.gov/pictures/cassinijupiter . It is also available from the University of Arizona's Lunar and Planetary Laboratory at http://ciclops.lpl.arizona.edu.

"This has been our first opportunity to exercise the Cassini flight and ground systems in a mode very similar to how we expect to operate at Saturn, and I'm extremely pleased with how it is working," said Bob Mitchell, Cassini program manager at NASA's Jet Propulsion Laboratory, Pasadena, Calif.

"The spacecraft is steadier than any spacecraft I've ever seen," said Dr. Carolyn Porco of the University of Arizona, team leader for the camera on Cassini. "It's so steady, the images are unexpectedly sharp and clear, even in the longest exposures taken and most challenging spectral regions."

At the same time, mission engineers at NASA are working with their counterparts at the European Space Agency (ESA) on a concern with the communication system on ESA's Huygens probe, which is attached to the Cassini spacecraft. Huygens is to drop from the Cassini spacecraft in late 2004 onto the large moon of Saturn called Titan as the Cassini orbiter begins its own exploration of the ringed planet and its system of moons.

The concern, which was identified in early September with tests at ESA's Operations Center at Darmstadt, Germany, involves the radio receiver supplied by ESA to receive signals from the Huygens probe as it descends through Titan's atmosphere. According to the tests, the signal sent to Cassini from Huygens will change in frequency as both spacecraft rapidly change position in relation to each other, much as a train whistle appears to change in pitch as it passes by a person standing alongside the tracks (called the Doppler effect). The engineering test found that the ESA-supplied receiver carried on the U.S. Cassini main spacecraft could not receive all the data from the Huygens probe.

"Cassini has given us the first tantalizing taste of its enormous scientific potential," said Dr. Jay Bergstralh, Cassini Program Scientist at NASA Headquarters, Washington, D.C. "The spacecraft has operated perfectly since its launch three years ago, so we can look forward to even greater things in the coming months. We are, of course, concerned about communications with the Huygens probe, but the best minds in the business are working on solutions."

ESA and NASA mission scientists and engineers are developing options to address the situation, including changing the trajectory of Cassini during the Huygens probe's entry into Titan's atmosphere. A plan of action is expected to be ready by next summer for review and approval by officials of ESA and NASA.

Additional information about Cassini is available online at:

http://saturn.jpl.nasa.gov.

Cassini is a joint mission of NASA, ESA, and the Italian Space Agency (ASI). JPL manages the Cassini program for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology in Pasadena.

Information on the Huygens probe is available from ESA at http://sci.esa.int/

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