On Target for Earth Flyby
August 11, 1999
With another flawless maneuver, the Saturn-bound Cassini spacecraft today successfully executed the final adjustment to its flight path for a flyby of Earth that will occur Tuesday, August 17 at 8:28 p.m. Pacific Daylight Time (August 18 at 03:28 Universal Time).
The spacecraft, launched on a mission to Saturn in 1997, is now precisely set to make its closest approach to Earth at an altitude of 1,166 kilometers (725 miles) over the eastern South Pacific at -23.5 degrees latitude and 231.5 degrees longitude. The spacecraft may be visible from small islands in that area, such as Pitcairn Island or Easter Island. Two successful flybys of Venus, next week's flyby of Earth, and a flyby of Jupiter in December 2000 all give Cassini the additional speed it needs to reach Saturn in 2004.
Cassini's onboard rocket fired as scheduled this morning at 8:30 a.m. Pacific Daylight Time (15:30 Universal Time) for 130 seconds, completing the final adjustments to the spacecraft's flight path before the Earth flyby.
Nine of Cassini's 12 scientific instruments will make observations of the Earth-Moon system during the spacecraft's passage, including studies of Earth's magnetic environment and images of the moon. Cassini's primary mission is to make up-close studies of Saturn, its rings, moons and magnetic environment while orbiting the ringed planet from 2004-2008. Upon arrival at Saturn in 2004, Cassini will release a probe called Huygens, provided by the European Space Agency, to drop via parachute to the surface of Saturn's big moon, Titan, which is thought to resemble a frozen, primordial Earth.
Today, Cassini is about 9 million kilometers (about 5.8 million miles) from Earth, traveling at a speed of about 58,000 kilometers per hour (about 36,000 miles per hour) relative to Earth. It has traveled 1.671 billion kilometers (1.038 billion miles) since launch from Cape Canaveral, Florida, on Oct. 15, 1997.
Cassini is an international mission of NASA, the European Space Agency and the Italian Space Agency, and is managed for NASA's Office of Space Science by NASA's Jet Propulsion Laboratory, Pasadena, Calif. JPL is a division of the California Institute of Technology (Caltech), Pasadena, Calif.
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.