The international Cassini-Huygens mission is poised to begin an extensive tour of Saturn, its majestic rings and 31 known moons. After nearly a seven-year journey, Cassini is scheduled to enter orbit around Saturn at 10:30 p.m. EDT, June 30, 2004.
“The Saturn system represents an unsurpassed laboratory, where we can look for answers to many fundamental questions about the physics, chemistry, evolution of the planets and the conditions that give rise to life,” said Dr. Ed Weiler, NASA’s Associate Administrator for Space Science, Washington.
Cassini was launched Oct. 15, 1997 on a journey covering 3.5 billion kilometers (2.2 billion miles), Cassini is the most instrumented and scientifically capable planetary spacecraft ever flown. There are 12 instruments on the Cassini orbiter and six on the Huygens probe. The mission represents the best technical efforts of 260 scientists from the United States and 17 European nations. The Cassini mission cost approximately $3 billion.
The Cassini/Huygens mission is a four-year study of Saturn. The 18 highly sophisticated science instruments will study Saturn’s rings, icy satellites, magnetosphere, and Titan, the planet’s largest moon.
The spacecraft will fire its main engine for 96 minutes during the critical Saturn Orbit Insertion (SOI) maneuver. The maneuver will reduce Cassini’s speed, so Saturn can capture it as an orbiting satellite. Cassini will pass through a gap between the planet’s F and G rings, swing close to the planet, and begin the first of 76 orbits around Saturn’s system. During the mission, it will have 52 close encounters with seven of Saturn’s 31 moons.
There are risks involved with orbit insertion, but mission planners have prepared for them. There is a backup in case the main engine fails, and the path through the ring plane was searched for hazards with the best Earth and space-based telescopes. Particles too small to be seen from Earth could be fatal to the spacecraft, so Cassini will turn to use its high gain antenna as a shield against small objects.
Saturn is the sixth planet from the sun, and it is the second largest in the solar system, after Jupiter. Saturn and its ring system serve as a miniature model for the disc of gas and dust that surrounded the early sun, which formed the planets. Detailed knowledge of the dynamics of interactions among Saturn’s elaborate rings and many different moons will provide valuable data for understanding how the solar system’s planets evolved.
The study of Titan, Saturn’s largest moon, is one of the major goals of the mission. Titan may preserve, in deep-freeze, many of the chemical compounds that preceded life on Earth. Cassini will execute 45 flybys of Titan within approximately 950 kilometers (590 miles) of the surface. This will permit high-resolution mapping of the moon with the Titan radar-imaging instrument. The radar can see through the opaque haze of Titan’s upper atmosphere.
“Titan is like a time machine taking us to the past to see what Earth might have been like,” said Dr. Dennis Matson, Cassini project scientist at NASA’s Jet Propulsion Laboratory (JPL), Pasadena, Calif. “The hazy moon may hold clues to how the primitive Earth evolved into a life-bearing planet,” he said.
On Dec. 24, 2004, Cassini will release the wok-shaped Huygens probe for its journey to Titan. Huygens is the first probe designed to descend to the surface of the moon of another planet, and the most distant descent of a robotic probe attempted on another object in the solar system. On Jan. 14, 2005, after a three-week ballistic freefall, Huygens will enter Titan’s atmosphere. It will deploy parachutes and begin 2.5 hours of intensive scientific observations. The Huygens probe will transmit data to the Cassini spacecraft, which will relay the information back to Earth.
JPL designed, developed and assembled the Cassini orbiter. A team at the European Space Technology and Research Center in Noordwijk, the Netherlands, managed the development of the Huygens probe. The Italian Space Agency provided the high-gain antenna, much of the radio system and elements of several of Cassini’s science instruments. JPL manages the overall program for NASA’s Office of Space Science.
For information about the Cassini-Huygens mission to Saturn and Titan on the Internet, visit:
http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov