At 12:55 pm today (BST; 11:55 UTC), the last transmissions from the Cassini spacecraft were received on Earth, showing that it had completed the “Grand Finale” phase of its almost 20-year-long mission to study the planet Saturn and its moons.
The signals confirmed that the craft had burned up – as planned – on its final dive into the planet’s atmosphere. This brings to an end the Longest orbital survey of an outer planet, which began 13 years and 76 days ago.
The Cassini-Huygens mission (a joint project of NASA and ESA) was launched on 15 October 1997. It consisted of two separate systems: the Cassini orbiter and the Huygens probe (designed to land on the surface of Saturn’s largest moon, Titan).
Its journey to Saturn was long and complicated, requiring the probe to pick up speed through a number of “slingshot” manoeuvres, where it surfed in the wake of Venus and Earth as they orbited the sun. During this time it earned its first Guinness World Records title, becoming the Heaviest spacecraft to reach the outer solar system.
Once it finally arrived in orbit around Saturn, on 1 Jul 2004, the record-breaking discoveries started to pour in. On 14 January 2005, its Huygens lander became the first probe to land on Titan, setting a new record for the Most remote planetary landing in the process.
On the way down, Huygens passed through what it measured to be the thickest atmosphere on a moon and a record for the Longest river system photographed on another world was set (rivers of liquid methane!).
Cassini, meanwhile, continued to orbit around Saturn, making occasional trips out to the moons Titan and Enceladus. It saw many record-breaking wonders over the course of its 293 orbital passes.
In 2005 it spotted the solar system’s Largest erupting ice plumes pouring from the frozen ocean moon Enceladus, and later flew straight through them. In 2009 it watched a lightning storm on Saturn that raged for more than eight months (the Longest-lasting lightning storm), and watched the light reflecting of the Largest methane sea on Titan.
Towards the end of its mission, in July 2013, it was able to flip around and take the amazing picture below: The First image to show Saturn, Earth, Mars and Venus in one shot – as tiny specks of light behind Saturn’s beautiful rings.
Eventually, however, Cassini’s fuel started to run out. Rather than risk a crash that might contaminate Saturn’s moons with Earth microbes, NASA decided to give Cassini a sort of burial at sea, de-orbiting the spacecraft to burn up like a shooting star in Saturn’s upper atmosphere.
You can find out more about the history-making mission on the NASA Jet Propulsion Laboratory YouTube channel.
