18 August 1999
The NASA/ESA Cassini-Huygens spacecraft bid goodbye to Earth as it completed a highly accurate pass by our planet and swung away towards its encounter with Saturn in 2004. The Earth flyby occurred at 5:28 CEST (3:28 UT) on 18 August and gave the space probe a 5.5 km per second boost in speed, propelling it towards the ringed planet, more than 1 billion kilometres away.
Engineers at ESA's control centre ESOC in Darmstadt, Germany, and NASA's Jet Propulsion Laboratory, in Pasadena, California, confirmed that the spacecraft came within about 1171 kilometres of Earth, as planned, passing over the eastern South Pacific. Cassini-Huygens may have been visible from small islands in that area, such as Pitcairn or Easter Island. The closest approach point is located at 23.5° South and 128.5° West.
"Everything worked just perfectly and we're very happy," said Jean-Pierre Lebreton, ESA project scientist for Huygens. "Now we're looking forward to an exciting mission of discovery inside the atmosphere and on the surface of Titan, the largest moon of Saturn."
The spacecraft remains in excellent condition as it continues its seven-year flight to Saturn. Having completed its cruise among the inner planets, Cassini-Huygens' future now lies in the cold, dark realm of the outer planets. It will pass by Jupiter on 30 December 2000; the giant planet's gravity will bend the spacecraft's trajectory, which will put it on course for arrival in orbit around Saturn on 1 July 2004.
During the Earth flyby, nine of the twelve scientific instruments on Cassini were turned on to gather data on the Earth/Moon system. The Huygens Probe and its six scientific instruments remained dormant during the Earth flyby. The next bi-annual in-flight Probe checkout activities will take place in mid-September.
The Cassini-Huygens mission is to study Saturn, its magnetic and radiation environment, moons and rings for four years. The European Space Agency's Huygens probe will separate from Cassini and parachute to the surface of Titan. Titan is especially interesting, not least because of its many Earth-like characteristics, including an atmosphere made up mostly of nitrogen and the presence of organic molecules in its atmosphere and surface. Lakes or seas of ethane and methane may be found on its surface.
Notes for editors:
Cassini-Huygens is a joint programme of NASA, ESA and the Italian Space Agency (ASI). The Cassini orbiter, built by NASA, and the Huygens probe, provided by ESA, were mated together and launched as a single package from Cape Canaveral, Florida, on 15 October 1997, by a Titan 4-B rocket. ASI provided Cassini's high-gain antenna.
Cassini-Huygens will enter orbit around Saturn on 1 July 2004. The Huygens probe will separate from Cassini to parachute through the atmosphere to the surface of Saturn's largest moon, Titan, in November that year.
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