Cassini’s Mission Enters New Chapter

The Cassini- Huygens Mission, a cooperative project by NASA, ESA and the Italian Space Agency, has been making tremendous progress in the past few weeks. The spacecraft has been in equatorial orbit of Saturn since last spring and is scheduled to complete its journey in September, 2017.

Since last spring Cassini has managed to orbit and has conducted flybys of Saturn’s icy moons: Dione, Hyperion and Enceladus. Now the mission is to change the spacecraft’s orbit to tilt it out of Saturn’s ring plane and gradually plunge into Saturn’s atmosphere marking the completion of its journey. This orbital choreography took place on the 23rd of January during which the second of five propulsive manoeuvres took place. The change in orbit will enable Cassini to encounter Titan, Saturn’s largest moon. Earl Maize, Cassini’s project manager at JPL (for those who don’t speak NASA, Jet Propulsion Laboratory), said “ Titan does all the heavy lifting. Our job is to get the spacecraft to a precise altitude and latitude above Titan, at a particular time, and these large propulsive maneuvers are what keep us on target to do that”. 

Angling Saturn via jpl.nasa.gov
The Cassini spacecraft takes an angled view toward Saturn, showing the southern reaches of the planet with the rings on a dramatic diagonal.

A gravity assist flyby of Saturn’s massive satellite will be set up by each of the propulsive manoeuvres in the series, thereby sending it to a higher inclination with respect to Saturn’s equator. On Jan 23rd, Cassini’s orbital speed was changed by about 6.8 metres per second, by a 35-second engine burn. 

Engineers are slowly increasing the tilt of the craft’s orbit with respect to Saturn’s equator. By late November, the spacecraft’s path will carry it above Saturn’s poles. This period will be known as the “F-ring orbits”, as Cassini will approach just outside the planets main rings. Cassini’s final event will be to pass the innermost rings 22 times but not before orbiting the F-ring 20 times.

We have an exciting year of Saturn science planned as we head for higher ground. And the views along the way should be spectacular,” said Linda Spilker, Cassini project scientist at JPL.