From Newsgroup: sci.space.news

http://www.jpl.nasa.gov/news/news.php?feature=6200

Saturn Spacecraft Not Affected by Hypothetical Planet 9
Jet Propulsion Laboratory
April 8, 2016

Contrary to recent reports, NASA's Cassini spacecraft is not experiencing unexplained deviations in its orbit around Saturn, according to mission managers and orbit determination experts at NASA's Jet Propulsion Laboratory in Pasadena, California.

Several recent news stories have reported that a mysterious anomaly in Cassini's orbit could potentially be explained by the gravitational tug
of a theorized massive new planet in our solar system, lurking far beyond
the orbit of Neptune. While the proposed planet's existence may eventually
be confirmed by other means, mission navigators have observed no unexplained deviations in the spacecraft's orbit since its arrival there in 2004.

"Although we'd love it if Cassini could help detect a new planet in the
solar system, we do not see any perturbations in our orbit that we cannot explain with our current models," said Earl Maize, Cassini project manager
at JPL.

"An undiscovered planet outside the orbit of Neptune, 10 times the mass
of Earth, would affect the orbit of Saturn, not Cassini," said William Folkner, a planetary scientist at JPL. Folkner develops planetary orbit information used for NASA's high-precision spacecraft navigation. "This
could produce a signature in the measurements of Cassini while in orbit
about Saturn if the planet was close enough to the sun. But we do not
see any unexplained signature above the level of the measurement noise
in Cassini data taken from 2004 to 2016."

A recent paper predicts that, if data tracking Cassini's position were available out to the year 2020, they might be used to help rule out some possible locations of the theoretical planet in its long orbit around
the sun.

Cassini's mission is planned to end in late 2017, when the spacecraft
-- too low on fuel to continue on a longer mission -- will plunge into Saturn's atmosphere.

The Cassini-Huygens mission is a cooperative project of NASA, ESA and
the Italian Space Agency. JPL, a division of the California Institute
of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate in Washington.

For more information about Cassini, visit:

http://www.nasa.gov/cassini

http://saturn.jpl.nasa.gov


News Media Contact

Preston Dyches
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-7013
preston.dyches@jpl.nasa.gov

2016-101

Updated on April 11 at 1:10 p.m. PDT to clarify details about the paper's prediction.

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