On 15 October 1997, the Cassini orbiter and its Huygens probe left Earth for a 20-year journey to Saturn. Neither of them returned to Earth, of course, but a huge amount of data and some remarkable photographs did.
The craft they called Cassini looked very, very teeny
’Gainst Saturn and its rings, each one aglow,
Collecting lots of data so that, a little later,
It could beam them back to Earth, so far below.
NASA’s little star had travelled very far:
Round Venus, using gravity-assist
(The experience was so nice that it went and did it twice).
Then Earth and Jupiter were on its list.
Then came Saturn’s turn, and we were soon to learn
Of the next phase in Cassini’s grand campaign:
Through Titan’s atmosphere the Huygens probe would disappear
And land upon a pebble-strewn terrain.
Enceladus came next: we just did not expect
Its plumes of icy water, which contains
Methane, hydrogen and salt, CO2 and – who’d have thought –
There’s silica, as microscopic grains1!
There’s so much more to tell about other moons as well,
Some mini-moons, quite titchy little things:
Anthe, Daphnis, Pallene are just three Cassini’s seen,
And ‘Peggy’ being ‘born’ among the rings2.
There she is – the blip on the outer edge of Saturn’s outermost ‘A’ ring!
Then Cassini, all alone, took a photo of its home,
The planet Earth within a ring-gap framed.
But NASA had intended that the journey would be ended
With a final death-plunge at the planet aimed . . .
It’s such a crying shame that, despite its world-wide fame,
Cassini had to end its quest of pics.
But its NASA-planned demise – to crash through Saturn’s skies –
Has made Cassini part of Planet Six3.
1. See https://saturn.jpl.nasa.gov/news/2529/
2. It seems that ‘Peggy’ might have fragmented since her first sighting, perhaps after a collision . . .
3. On 15 September, 2017. RIP.