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A GREAT CALL

Cassini Phones Home

Difficult to say that the phone call was the most astounding, as to the successful mission up to this day of the Cassini Spacecraft — the tiny craft has passed through space for several years by mere propulsion from it’s launch alone, managed to remain unharmed by all and any passing space junk or otherwise collisions with neighborhood particles in the great beyond all those years, arrived on time and apparently safely and exactly where it’s supposed to be, then managed to pass successfully and unharmed through the rings of the planet, Saturn, not once but twice, and all that, just to phone home.

Talk about successful engineering! Truly astounding. I watched the celebratory clapping by the staff responsible for these truly incredible events, and found it even more amazing that they were still going back to work after their polite and highly modulated group celebration, such as it was. If only the rest of humankind could be so well organized, humble, even, at just such great work as these people can take credit for.

Science – AP
SPACECRAFT CASSINI ENTERS SATURN’S ORBIT
11:10 PM PST 06/30/04, By JOHN ANTCZAK, Associated Press Writer

PASADENA, Calif. – The international Cassini spacecraft threaded a gap between two of Saturn’s dazzling rings late Wednesday and entered orbit around the giant planet, completing one of the mission’s most critical maneuvers more than 900 million miles from Earth.

Mission control at NASA’s Jet Propulsion Laboratory erupted in cheers shortly before 9 p.m. PDT when a radio signal indicated Cassini had been captured by Saturn.

“It was kind of a nail-biter throughout but what you saw here was the result of a lot of work on the part of a lot of people and it all paid off just perfect,” said Robert Mitchell, the Cassini program manager at JPL.

Propulsion engineer and mission commentator Todd Barber said the announcement came earlier than predicted because the signal had been tracked so well.

“We have burn complete,” Barber announced later when the spacecraft’s rocket stopped firing, apparently within one second of the predicted 9:12 p.m. time.

The maneuver, which brought Cassini within 12,500 miles of Saturn’s cloud tops, came after two decades of work by scientists in 18 nations.

The craft could have simply flown past Saturn if the burn failed to brake its acceleration properly.

Cassini was programmed to perform a high-speed ballet, turning its big radio dish forward to shield against particles as it ascended through the rings, pirouetting to point its engine forward and fire, then spinning around to put the shielding antenna forward again for a descent back through the rings.

The $3.3 billion mission, funded by U.S. and European space agencies, was designed to give scientists at least a four-year tour of Saturn and some of its 31 known moons. Cassini is scheduled to make 76 orbits and repeated fly-bys of the moons.

Scientists hope the mission will provide important clues about how the planets formed. Saturn, the sixth planet from the sun and the second-largest, intrigues scientists because it is like a model of the early solar system, when the sun was surrounded by a disk of gas and dust.

Cassini has traveled 2.2 billion miles since it was launched in 1997, getting gravitational assists from Earth and Venus as it caromed around the solar system.

The spacecraft took the roundabout route because the 22-foot-long, 13-foot-wide craft was too massive to be launched on a direct trajectory to Saturn.

Cassini also carried with it a probe ? named Huygens ? to be sent into the atmosphere of Saturn’s big moon Titan in January. The moon, blanketed by a thick atmosphere of nitrogen and methane, is believed to have organic compounds resembling those on Earth billions of years before life appeared.

Cassini and its probe are named for 17th-century astronomers Jean Dominique Cassini and Christiaan Huygens.

Previous expeditions to Saturn were brief. There were fly-bys by Pioneer 11 and the Voyager missions from 1979 to 1981.

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