The grand finale - Cassini's last dive

15 September 2017

Cassini finale

Illustration of the Cassini spacecraft above Saturn's northern hemisphere prior to one of its 22 grand finale dives.
(Credit: NASA / JPL-Caltech)

Scientists across the UK are today saying a fond farewell to the landmark Cassini Space Mission, which was launched almost 20 years ago.

The probe will end its journey with a dramatic dive into Saturn’s atmosphere, where it will be crushed and vaporised.

The original Cassini-Huygens mission launched in October 1997, with the involvement of teams of scientists from across the globe.

The UK had its part to play in the mission, as various universities and the Science and Technology Facilities Council (STFC) contributed hardware and expertise.

Cassini has made some significant discoveries, as it found three of Saturn’s 62 moons – and gathered evidence of water on one of these.

In 2005, Cassini released the European Space Agency’s (ESA) Huygens probe and it became the first probe to land successfully in the outer solar system. It gave scientists their first look at the surface of Titan, the largest moon of Saturn.

STFC’s RAL Space played a role in developing and building Cassini-Huygens, a huge collaboration between NASA, ESA and ASI, the Italian Space Agency.

RAL Space Project Manager Dr Jane Hurley, who was previously part of the Oxford University team and helps to analyse the infrared data which comes from Cassini’s CIRS instrument, said: “Cassini has provided the international science community with decades of irreplaceable insight into Saturn and its moons, and inspiration to generations of scientists and engineers.

“As part of both the CIRS instrument science team and operations team, I have been very lucky to be part of such a successful mission - not least because of the collaborations and working relationships that become lifelong friendships.

Titan Huygens

Artist’s impression of one of the first-ever images from beneath Titan's thick cloud layers, sent back by the Huygens probe in 2005. Smooth stones, possibly containing water-ice, are strewn about the landscape. Analyses of Huygens’ images and data show that Titan's surface today has intriguing similarities to the surface of the early Earth.
(Credit: ESA)

“I shall be raising a glass with the Oxford University team to toast to the Cassini/CIRS operations team in the UK, Europe, at NASA/Goddard and NASA/JPL for the years of hard work behind the scenes that have given us the mission we’re celebrating.”

RAL Space worked with the Open University on the Huygens Surface Science Package (SSP), which analysed Huygen’s descent from Cassini through Titan’s atmosphere and Titan’s rocky surface.

RAL Space also collaborated on the Cassini Plasma Spectrometer (CAPS) and the Cosmic Dust Analyser (CDA.) For CAPS, we built a high voltage power supply board and for the CDA we built the Chemical Analyser electronics which measured the time-of-flight of ions, telling us the chemical composition of interplanetary dust grains.

Scientists from Oxford University were involved in the construction of one of the mission’s main instruments, the Composite Infrared Spectrometer (CIRS). CIRS measures the heat emitted by a planet’s atmosphere or surface, and reveals the individual elements present in the minerals and gasses, revealing their chemical make-up.

Oxford University team leader Professor Patrick Irwin said: “Speaking personally, the Cassini mission is as old as my marriage, which took place two months before the launch, and I and my wife were lucky enough to witness the launch in 1997.

“Together with losing a key, unique stream of data I will miss the camaraderie of the international Cassini/CIRS team and will miss being able to look up at Saturn and think ‘I helped build something in orbit about that!’.

“Our design, construction and testing of the CIRS cooler was a job well done and it still amazes me what we achieved with relatively little resource.”

As Cassini takes its final dive, the instruments on board will continue to send back data about Saturn’s atmosphere until it loses contact with Earth at around 11:30am.

Becky Parker-Ellis
STFC Media office
01793 444564

Science and Technology Facilities Council Switchboard: 01793 442000