The one on Saturn does not drift and is already as far north as it can be.
‘The polar hurricane has nowhere else to go, and that’s likely why it’s stuck at the pole,’ said Kunio Sayanagi, a Cassini imaging team associate at Hampton University in Hampton, Va.
Scientists believe the massive storm has been churning for years.
When Cassini arrived in the Saturn system in 2004, Saturn’s north pole was dark because the planet was in the middle of its north polar winter.
During that time, the Cassini spacecraft’s composite infrared spectrometer and visual and infrared mapping spectrometer detected a great vortex, but a visible-light view had to wait for the passing of the equinox in August 2009.
Only then did sunlight begin flooding Saturn’s northern hemisphere.
The view required a change in the angle of Cassini’s orbits around Saturn so the spacecraft could see the poles.
‘Such a stunning and mesmerizing view of the hurricane-like storm at the north pole is only possible because Cassini is on a sportier course, with orbits tilted to loop the spacecraft above and below Saturn’s equatorial plane,’ said Scott Edgington, Cassini deputy project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.
‘You cannot see the polar regions very well from an equatorial orbit.
‘Observing the planet from different vantage points reveals more about the cloud layers that cover the entirety of the planet.’
Cassini changes its orbital inclination for such an observing campaign only once every few years.
Because the spacecraft uses flybys of Saturn’s moon Titan to change the angle of its orbit, the inclined trajectories require attentive oversight from navigators.
The path requires careful planning years in advance and sticking very precisely to the planned itinerary to ensure enough propellant is available for the spacecraft to reach future planned orbits and encounters.
By Mark Prigg | DailyMail