Saturn’s north pole Hexagon © NASA
On Friday 15 September 2017 the Cassini spacecraft will end its mission by burning up in the atmosphere of Saturn. We look back as some of the amazing photographs and images taken by the instruments on the probe.
Infrared view of clouds in Saturn’s northern hemisphere © NASA
There are 32.7kg of radioactive plutonium fuel on-board Cassini
Saturn moon Iapetus © NASA
Iapetus’ orbit is so wide you would be able to see the rings of Saturn from the surface.
Rings around Saturn © NASA
The Cassini spacecraft weighs 2,150kg, around the same as two walruses.
Saturn casts a shadow in its rings © NASA
As of July 2017, Cassini has taken some 379,300 images.
Saturn in full © NASA
There has been more than 3,600 scientific papers published with Cassini data.
Earth (indicated by arrow) seen behind Saturn © NASA
Saturn is the most distant planet in the Solar System that is obviously visible to the human eye from Earth.
North pole of Saturn in approximate true colour © NASA
When Cassini begins its death plunge it will be on its 293rd orbit of Saturn.
Enceladus © NASA
Cassini has been programmed to disintegrate in Saturn’s atmosphere so that it doesn’t crash into its moons and contaminate the surface. This is particularly important for Enceladus, which is our most promising candidate for finding extra-terrestrial life.
Jupiter and IO © NASA
In 2000 Cassini made a flyby of Jupiter for course correction and acceleration.
Panoramic of Saturn’s rings © NASA
Saturns rings measure 273,000km across, yet are only 20km thick.
Saturn moon Phoebe © NASA
Phoebe is only 200km across and its low density means ice is a major constituent.
Saturn moon Epimethus with Titan in the background © NASA
Cassini has discovered 10 new moons around Saturn, with six confirmed, three provisional and one that potentially temporary.
Iapetus’ mountain range © NASA
This mountain range exactly over the equator of Iapetus is 20km high and was probably formed from debris from Saturn’s ring system.
Saturn moon Mimas © NASA
Mimas has a large crater named after William Herschel, who discovered the moon in 1789 – it looks eerily like the Death Star from Star Wars.
Geysers of Enceladus © NASA
The spacecraft’s top speed was 122,900 km/h.
Storms on Saturn © NASA
Storms like this in the northern hemisphere of the planet occur every 30 years.
Brann © NASA
Cassini was in the shadow of Saturn when it took this photo. Mars, Venus, Earth and the Moon can all be seen around the edge of the planet, and the outer purple band is formed from dust and ice particles from the geysers of Enceladus.
Titan’s topography © NASA
The dark areas on the surface of Saturnian moon Titan are lakes of liquid ethane and methane.
Ring King © NASA
Cassini was launched on 15 October 1997 and arrived in orbit of Saturn on 1 July 2004.
Saturn moon Tethys © NASA
Since April Cassini has been performing daring plunges between the clouds and rings of Saturn, with the hope of being able to weigh the rings. If they prove to be low-mass it means they must be relatively new, else they would have eroded away over time.
Tethys and Enceladus align © NASA
The mission will cost around $3.26bn in total, with the European Space Agency contributing $500m to the total.
Saturn moon Hyperion © NASA
Hyperion is a small moon (360x260x205km) with an chaotic rotation.
Saturnian moon Tethys © NASA
The Cassini spacecraft is named after Italian-French astronomer Giovanni Domenico Cassini, who discovered Saturn’s ring divisions and four of its moons.
Infrared image of Titan © NASA
Due to being further from the Sun and at a lower temperature, the clouds form at a deeper level in the atmosphere compared to Jupiter making them less striking (though still beautiful in our eyes).
Saturn moon Daphnis © NASA
Although on eight kilometres wide, Daphnis creates a gravitational pull on Saturn’s rings causing a ripple effects.
The Saturnian moon Phoebe © NASA
Cassini passed within 12,000km of Phoebe to take this shot, a tiny distance in astronomy.
Saturn’s north pole © NASA
The tumultuous cyclone at Saturn’s north pole is 8,000km across with clouds measuring tens of kilometres tall.
Impact Site: Cassini’s Final Image © NASA
It seems fitting that the final image in this collection should be the last one taken by the Cassini probe as it made its descent into Saturn’s atmosphere. Taken on 14 September 2017 at 19:59 UTC (spacecraft event time) and at a distance of 634,000 kilometers above the planet, this photo is the final record of Cassini’s 13-year journey.
Discover more about NASA’s Cassini probe and mission before its final plunge into the planet’s atmosphere in Cassini’s Last Hurrah from issue 310 of BBC Focus magazine – make sure you don’t miss out on the full article every issue and subscribe here.
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