Spacecraft flyby paints new picture of Jupiter
First 'double team' study by 2 spacecraft successful
PASADENA, California (CNN) -- Scientists at Pasadena, California's Jet Propulsion Laboratory are proclaiming victory in today's flyby of Jupiter by the unmanned spacecraft Cassini. The spacecraft worked in concert with another unmanned vehicle, Galileo, to transmit new images of our solar system's largest planet back to Earth.
The primary goal of the experiments is to study the effect of solar wind on Jupiter's magnetic field. The study captured data for the first time showing that atoms from the solar wind were escaping the magnetic field, scientists said during a news conference on Saturday.
The solar wind consists of streams of ionized gas particles flowing from the sun, which gently push matter throughout the solar system.
The scientists said the next step was to attempt to measure the changes in Jupiter's magnetic field created by the solar wind. Experts want to know whether the atoms registered by the experiment were escaping the magnetic field because of the solar wind's effect or because of natural fluctuations in the field itself.
Other images from Galileo and Cassini offer a chance to learn more about Jupiter's weather patterns and about volcanic activity on its moon, Io.
Cassini, a joint project by NASA and the European and Italian space agencies, passed Jupiter at about 2 a.m. PST on Saturday at a distance of 10 million kilometers (6 million miles), primarily to gain a slingshot-like boost from the planet's gravity to help the spacecraft reach the planet Saturn by July 2004.
But Galileo, in permanent orbit around Jupiter, may be the real hero of the mission. It has outlived its designed two-year life span by three years, giving scientists the opportunity to use their so-called "double team" method of studying the planet.
A film by Cassini
NASA released Cassini's first color movie of Jupiter earlier this week. The short clip presents the entire circumference of the planet, flattened into the form of a rectangle.
Like a similar map of the Earth, the most extreme northern and southern latitudes are stretched out considerably. The smallest discernable details at the equator are about 600 kilometers (about 370 miles) across.
In the video, the Great Red Spot swirls, orange and white storm bands slide against each other and black dots appear to reveal the shadow of passing moons in the video, which spans 24 Jupiter rotations between October 31 and November 9.
To the east (right) of the Red Spot, oval storms roll over each other like ball bearings. Small, bright features appear quickly and randomly in turbulent regions, possible signs of lightning storms. The smallest visible features at the equator are about 600 kilometers (370 miles) across. In a map of this nature, the most extreme northern and southern latitudes are unnaturally stretched out.
Scientists are interested in Jupiter's weather patterns in hopes of using their data to learn more about weather patterns on Earth.
Production trouble
On Thursday, Cassini, which cost $3.4 billion, was forced to switch to a different maneuvering system. Engineers said they suspect the problem began when a lubricant on the wheel was gradually reduced, causing friction on the bearings.
Cassini's wheels point the spacecraft. When an electric motor spins one of the wheels, the spacecraft rotates in the opposite direction.
The wheel system has been trouble-free since it was put back in operation December 21, the Jet Propulsion Laboratory said. The JPL manages the mission for NASA, the U.S. space agency.
Coming attractions
Other synchronized studies of the largest planet in the solar system are in the works. Before Cassini leaves the Jupiter system, it will take pictures of the planet's night-side aurora in January.
At the same time, back in Earth orbit, the Hubble telescope, orbiting Earth, will train its powerful lens on Jupiter's day-side aurora.