NASA Saturn mission makes first ring-grazing plunge

Washington, December 6:NASA said its Cassini spacecraft has successfully made the first close dive past the outer edges of Saturn s rings since beginning its penultimate mission phase on November 30, but did not obtain views of the planet near the time of closest approach."Cassini s imaging cameras obtained views of Saturn about two days before crossing through the ring plane, but not near the time of closest approach," NASA said in a statement on Monday."The focus of this first close pass was the engine maneuver and observations by Cassini s other science instruments. Future dives past the rings will feature some of the mission s best views of the outer regions of the rings and small, nearby moons," it added.Cassini crossed through the plane of Saturn s rings on Sunday at a distance of approximately 91,000 kilometres above Saturn s cloud tops.This is the approximate location of a faint, dusty ring produced by the planet s small moons Janus and Epimetheus, and just 11,000 kilometres from the centre of Saturn s F ring.About an hour prior to the ring-plane crossing, the spacecraft performed a short burn of its main engine that lasted about six seconds.About 30 minutes later, as it approached the ring plane, Cassini closed its canopy-like engine cover as a protective measure.A few hours after the ring-plane crossing, Cassini began a complete scan across the rings with its radio science experiment to study their structure in great detail."It s taken years of planning, but now that we re finally here, the whole Cassini team is excited to begin studying the data that come from these ring-grazing orbits," said Linda Spilker, Cassini project scientist at NASA s Jet Propulsion Laboratory, Pasadena, California."This is a remarkable time in what s already been a thrilling journey," Spilker said.Each of Cassini s orbits for the remainder of the mission will last one week.The next pass by the rings outer edges is planned for December 11.The ring-grazing orbits -- 20 in all -- will continue until April 22, when the last close flyby of Saturn s moon Titan will reshape Cassini s flight path.With that encounter, Cassini will leap over the rings, making the first of 22 plunges through the 2,400-kilometre gap between Saturn and its innermost ring on April 26.On September 15, the mission will conclude with a final plunge into Saturn s atmosphere, NASA said.Launched in 1997, Cassini has been touring the Saturn system since arriving there in 2004 for an up-close study of the planet, its rings and moons.