Mullard Space Science Laboratory

P R E S S  R E L E A S E

28 June 2004
REF: CASS2004-1


On 1 July, after a 7-year journey of almost 3.5 billion km through space, the Cassini-Huygens spacecraft will arrive at its destination, Saturn. This will be the first spacecraft to orbit the ringed planet, and the first to fly over the rings.

The Cassini orbiter carries an 'electron spectrometer' instrument built at University College London's Mullard Space Science Laboratory, in Holmbury St Mary, which will tell us more about Saturn's magnetic field and the spokes in Saturn's rings.

'We are privileged to be part of one of the great exploratory missions of our time' says Dr Andrew Coates, team leader at MSSL. 'The ringed giant planet, its 31 moons and its enormous magnetic field provide a fascinating laboratory where we can learn more about how the solar system formed'.

On 1 July as the craft flies just 20,000 km above Saturn's swirling clouds, an on-board rocket engine will fire for 96 minutes to slow the spacecraft and capture it into Saturn's orbit. Immediately afterwards, the spacecraft will make unique measurements just above Saturn's rings.

'This is the first major target for us. Conditions in Saturn's rings resemble those in the early solar system where dust, light and electrons were present. We will be looking for electrical charging effects in the rings' says Dr Coates.

Cassini's four year tour of discovery around Saturn starts on July 1. Cassini will orbit Saturn and conduct close flybys of many of the planet's moons. There will be 45 flybys of Titan, the largest moon, where a dense nitrogen based atmosphere with a hydrocarbon haze shrouds the surface, and many close flybys of smaller, icy moons. Part of MSSL's work will be studying how particles from Titan's atmosphere, and from the icy moons, affect the Saturn magnetosphere.

Titan's surface temperature is -180 degrees C - and hydrocarbon rain may fall into methane/ethane seas. The atmosphere resembles that of the early Earth soon after its formation 4.6 billion years ago. The Huygens probe will be released on Christmas Day; it will plunge through Titan's atmosphere and land on 14 January.

Saturn's giant magnetic field carves out a cocoon in the fast-flowing solar wind, 20 times the size of Earth's magnetosphere. This makes the timescales for movement of the charged particles inside much longer than those at Earth. Information from how Saturn's magnetosphere works will really test theories of our own magnetic environment.

Dr David Linder, project manager at MSSL for the electron spectrometer, says 'The excitement is really building as we approach Saturn. The instrument is working excellently and our fingers are crossed for going into orbit on July 1.'


Notes to Editors:

1. The Mullard Space Science Laboratory, situated at Holmbury St Mary, is the Department of Space and Climate Physics of University College London. About 120 people work on space science and space engineering. The Laboratory plays key roles in many missions of space exploration. Over 250 instruments have been launched into space to date, to study astrophysics, solar and stellar physics, plasma and planetary physics and climate physics.

2. The electron spectrometer (ELS) is one of three sensors in the Cassini Plasma Spectrometer instrument (principal investigator Dr D.T. Young at Southwest Research Institute, San Antonio, Texas). RAL and FFI (Norway) also contributed hardware for ELS.

3. Images are available on request

C O N T A C T S:

Mullard Space Science Laboratory
University College London
Holmbury St. Mary, Dorking
Surrey, RH5 6NT

MSSL switchboard: 01483 204100
MSSL website:

Dr Andrew Coates:  Lead co-investigator at MSSL
Dr David Linder:  Project manager at MSSL
Dr Abigail Rymer:  Scientist
Hazel McAndrews:  Scientist
Dr Gethyn Lewis:  Operations scientist
Lin Gilbert:  Software