Cassini Completes Earth Flyby
August 17, 1999
Earthlings bid farewell to the Cassini spacecraft tonight as theSaturn-bound mission successfully completed a highly accurate pass of Earth at 8:28 p.m. Pacific Daylight Time (03:28 Universal Time August 18). The
flyby gave Cassini a 5.5-kilometer-per-second (about 12,000-mile-per-hour) boost in speed, sending the spacecraft on toward the ringed planet more than 1 billion kilometers (almost one billion miles) away.
Engineers at NASA's Jet Propulsion Laboratory confirmed that the spacecraft flew past Earth at an altitude of about 1,171 kilometers (727 miles), passing most closely above the eastern South Pacific at -23.5 degrees latitude and 231.5 degrees longitude. Cassini may have been visible from small islands in that area, such as Pitcairn Island or Easter Island.
The spacecraft remains in excellent health as it continues along its seven-year-long journey to Saturn. Having completed its cruise among the inner planets, Cassini's future now resides in the cold, dark realm of the outer planets. The spacecraft will pass by Jupiter on December 30, 2000; the giant planet's gravity will bend Cassini's flight path to put it on course for arrival into orbit around Saturn on July 1, 2004.
Cassini's mission is to study Saturn, its moons, elaborate rings, and its magnetic and radiation environment for four years. Cassini will also deliver the European Space Agency's Huygens probe to parachute to the surface of Saturn's moon Titan. Titan is of special interest partly because of its many Earthlike characteristics, including a mostly nitrogen atmosphere and the presence of organic molecules in the atmosphere and on its surface. Lakes or seas of ethane and methane may exist on its surface.
The Cassini/Huygens program is a joint endeavor of NASA, the European Space Agency and the Italian Space Agency. The Cassini orbiter, built by NASA, and the Huygens probe, provided by the European Space Agency (ESA), were mated together and launched as a single package from Cape Canaveral, Florida, on October 15, 1997. Cassini's dish-shaped high-gain antenna was provided for the mission by the Italian Space Agency. At Saturn, the Huygens probe will detach from Cassini to parachute to the surface of Titan on November 30, 2004.
Nine of Cassini's 12 science instruments were turned on to make observations of the Earth/Moon system. Scientific and engineering data from the Earth flyby will be transmitted by Cassini to receiving stations of NASA's Deep Space Network over coming days.
The mission is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA. JPL is a division of the California Institute of Technology. More information about the Cassini mission is available at http://saturn.jpl.nasa.gov.
Additional information about Cassini-Huygens is online at http://saturn.jpl.nasa.gov.
Cassini will begin orbiting Saturn on July 1, 2004, and release its piggybacked Huygens probe about six months later for descent through the thick atmosphere of the moon Titan. Cassini-Huygens is a cooperative mission of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Office of Space Science, Washington, D.C.