Can’t hear Cassini anymore

The Cassini Spacecraft transmitted its last message on September 15, 2017. Cassini had traversed the cosmos for 13 years, completing 293 orbits, took over 400,000 photos, measured over 600 GB of data, and discovered at least 7 new moons. The last message, sent as the spacecraft was burning up in Saturn’s atmosphere, was the final breath of a spacecraft that brought to the world images of our cosmos that were never seen.

The mission originally ended in 2008 but Cassini just didn’t stop. Scientists thought that if they just let Cassini run out of fuel it might crash into an untouched moon, contaminating the search for life. So, they decided to smash Cassini into Saturn. Cassini’s silicon and aluminium body disintegrated in a fireball until finally Cassini’s fuel, its plutonium core, melted away.

But how did Cassini get there in the first place?

NASA and the European Space agency launched Cassini in 1997, wanting to know what was going on around Saturn, following the interest generated by the Voyager 1 and Voyager 2 probes. The challenge was to get Cassini into Saturn’s orbit, close enough to Saturn to have a stable path as a satellite, but not so close that it crashes and burns accidentally.

To get Cassini to Saturn, the spacecraft swung past Venus twice, picking up speed, then back by Earth and on past Jupiter. It wasn’t until 2004 that Cassini reached a stable orbit around Saturn. Meaning it took 7 years and 3.4 billion kilometres to travel to its destination.

Cassini looks out

Cassini was designed and launched just to be a floating lab. It contained 12 scientific instruments, that were designed to paint a picture of Saturn and the surrounding space unlike anything that had come before it. The spacecraft was really just a way to launch these instruments into space and hear what they would say. And they have told us loads. Not only did Cassini send back amazing images, but it sent data that has illuminated our cosmos and sparked serious thought about the origin of life. Cassini stared out into the blackness of space, and whispered back some of the secrets of the universe: of life on other planets, on earth’s origin and existence, and on the great expanse we inhabit.

Artist’s impression of Cassini. Via NASA/JPL

Why Cassini?

The Cassini spacecraft bought to the world images of our outer planets that were mind-bending. Of Saturn’s rings, its amazing moons of dense nitrogen and icy volcanoes, of the 7 year long seasons and a hexagonal shaped storm. Saturn is far from ordinary, and far from completely understood. The data that has been gathered over 7.9 billion kilometres, with help from 27 participating nations, tells us about our solar system, and our place in it.