Although PlanetX may eventually be proven to exist, it is NOT TRUE that a mysterious force is changing the course Saturn's Cassini spacecraft.
There have been multiple reports of a mysterious planet pulling at Cassini, a spacecraft designed to take detailed measurements of Saturn's atmosphere and rings. Although NASA is open to the idea that there may be an additional undiscovered planet, they have reassured us that there have been NO unexplained changes in the orbit of Cassini. Here is NASA's response to the UNTRUE stories:
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.
"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."
Again, NASA does not deny the fact that there might be a hypothetical 9th planet, but they reject stories claiming that the Cassini probe has anything but a stable orbit.