Wednesday 2 May 2012

JUICE is Go!

The Jupiter Icy Moons Explorer (JUICE) will explore the giant planet and its diverse collection of icy worlds, from volcanic Io, to the waterworlds Europa and Ganymede, to the ancient cratered terrain of Callisto.
Billion euro Jupiter mission approved
Joint release on behalf of Imperial College London, Oxford University, University of Leicester, and University College London; with thanks to Pete Wilton of the Oxford University Press Office.

The European Space Agency (ESA) has approved a new mission to explore Jupiter and its icy moons to reveal fresh insights into the habitability of the ‘waterworlds’ orbiting the giant planets in our solar system and beyond.

On 2 May 2012, at a meeting in Paris, ESA’s Science Program Committee voted to go ahead with the project, the Jupiter Icy Moons Explorer (JUICE), the first European-led mission to the outer solar system, and the first spacecraft destined to orbit an icy moon. The JUICE spacecraft is scheduled to launch in 2022, arriving in the Jupiter system in 2030.

Approval for the estimated billion euro contract for the mission came with UK researchers deeply involved in the leadership and planning for JUICE and playing a vital role in gaining approval for the mission ahead of rival bids. The proposal was led by a UK scientist and UK scientists make up four of the 15 members of the ESA Science Study Team for JUICE with the team including researchers from Imperial College London, Oxford University, University of Leicester, and UCL (University College London). 

The primary target of the mission is the solar system’s largest moon, Ganymede, an icy world 8% larger than the planet Mercury. Ganymede is unique within the solar system – it is thought to harbour a deep ocean under the icy crust, it has its own internally generated magnetic field, and it has an ancient surface littered with more individual types of crater than anywhere else in the solar system. 

If moons are common features of giant planets around other stars, then Ganymede may represent a whole class of potentially habitable environments in our galaxy. JUICE will carry experiments designed to study the sub-surface ocean, the geology and composition of the surface, and its interaction with its plasma environment, to assess its potential as a habitable environment in our solar system. The spacecraft will also investigate Jupiter’s other icy worlds, Callisto and Europa, as well as the giant planet’s complex atmosphere and extended magnetosphere.

Imperial, Oxford, Leicester and UCL will be among the UK institutions working to propose experiments to be carried as part of the spacecraft payload. These instruments will be specifically designed to study the gas giant, its icy moons and charged particle environment to an unprecedented level of detail, giving our most detailed characterisation of the Jovian system ever obtained.

Professor Michele Dougherty of Imperial College London, lead scientist for the JUICE proposal, said: ‘Ever since Galileo’s discovery of the four largest moons of Jupiter, we’ve wondered what it must be like on their icy surfaces, looking into a night sky dominated by the gas giant Jupiter. From the volcanic moon Io, to the potential sub-surface oceans of Europa and Ganymede and the ancient cratered terrain of Callisto, these four moons are fascinating worlds in their own right.’

As well as making close measurements of the surface, sub-surface, magnetic and plasma environment of Ganymede the mission will also focus on the other icy moons; performing multiple flybys of Callisto and two flybys of Europa. By studying all three of these icy environments the mission’s studies of Ganymede will take on a broader significance. 

Dr Leigh Fletcher of Oxford University, a member of the ESA Science Study Team for JUICE, said: ‘Scientists have had a lot of success detecting the giant planets orbiting distant stars, but the really exciting prospect may be the existence of potentially habitable ‘waterworlds’ that could be a lot like Ganymede or Europa. One of the main aims of the mission is to try to understand whether a ‘waterworld’ such as Ganymede might be the sort of environment that could harbour life.’ 

In order to assess whether Jupiter and its moons could provide habitable environments, and provide a model for gas giant systems orbiting other stars, the spacecraft will make an extensive study of the planet’s dynamic, evolving atmosphere, with its belts, zones and gigantic swirling storms, over the 3-year duration of the mission. JUICE will also study the magnetic and charged particle environment of Jupiter, which has the largest magnetosphere in the solar system, and its coupling to the moons (particularly Ganymede).

Dr Emma Bunce of the University of Leicester, deputy lead scientist for the JUICE proposal, said: ‘We need to place the possible habitability of these “waterworlds” into some broader context, and JUICE will do that by also studying the surrounding environment. Ganymede is strongly coupled to its parent Jupiter - through gravitational and electromagnetic forces – studying this interaction gives us further insight into its unique place in the solar system.’

Professor Andrew Coates of UCL, a member of the ESA Science Study Team, said: ‘Studying these watery worlds is the next vital step beyond Mars in the search for the conditions for life in our solar system. Ganymede’s unique magnetic shield helps protect it somewhat from Jupiter’s harsh radiation belts and rapidly rotating magnetosphere, and we want to understand its effectiveness. Europa and Callisto provide key comparisons as we search for the solar system’s ‘sweet spots’ for habitability.’

The data JUICE will send back about the varied environments of Jupiter and its icy moons will benefit many areas of science with geologists, astrobiologists, space and atmospheric physicists all queuing up to see how the mission’s findings will affect their disciplines.

The announcement will lead to further opportunities for British companies as they look to bid for contracts to build elements of the JUICE spacecraft and its instruments. The UK Space Agency estimates that the space industry's overall contribution to UK GDP is £7.9 billion and that it employs nearly 27,000 people, with around 60,000 more jobs enabled by the space sector.

For further information contact:

Professor Michele Dougherty of Imperial College London on mobile; +44 (0)7990 973761 or email OR Simon Levey on +44 (0)207 5946702 or email

Dr Leigh Fletcher of Oxford University on +44 (0)1865 272089 or email

Dr Emma Bunce of the University of Leicester on +44 (0)116 2523541 or email

Professor Andrew Coates of University College London on mobile; +44 (0)7788 448318 or email

Alternatively contact the University of Oxford Press Office on +44 (0)1865 283877 or email

Notes to editors

*The selection of the Jupiter mission is the culmination of five years of hard work by the ESA team of scientists and engineers. ESA’s Cosmic Vision L-class competition started in March 2007 with a call to the scientific community to propose new ideas for future exploration.  A previous incarnation of JUICE was selected as one of three finalists (JUICE, Athena, and NGO), which have been going head-to-head in the ESA studies since 2010. At that time, all three proposals had significant US involvement, and the Jupiter mission was known as the Europa Jupiter System Mission (EJSM/Laplace). However, in March 2011, NASA withdrew from the L Class missions in general, and the reformulation phase began to rework the three proposals into European-led missions, leading to the evolution of the JUICE spacecraft.

*The JUICE mission relies on a strong heritage of outer solar system exploration by UK scientists, such as those involved in the Cassini-Huygens mission to Saturn and Titan.
*For more on how the space industry benefits the UK see: ‘The Size and Health of the UK Space Industry’, November 2012:

Destination: Ganymede

Galileo views Ganymede
Oxford Science Blog By Pete Wilton & Leigh Fletcher, to accompany the press release here.
It’s official: it was announced today that Oxford University scientists will help to prepare a mission to Jupiter and its icy moons.

But whilst the JUICE spacecraft will beam back valuable data on several of the planet’s satellites, it will give special attention to one in particular: Ganymede.

I asked Leigh Fletcher of Oxford University’s Department of Physics, one of the JUICE team, about the appeal of Ganymede, what they hope to find there, and how Oxford scientists will probe the secrets of this enigmatic ‘waterworld’…

OxSciBlog: What makes Ganymede so interesting?
Leigh Fletcher: When people think of moons in our solar system, they often imagine them as being inferior to the main planets, and somehow less interesting. The moons of Jupiter show how wrong that misguided assumption can be - the four largest Jovian moons (Io, Europa, Ganymede, and Callisto) are the size of planets, and each has a fascinating and rich geologic and chemical history. 
These moons truly are worlds in their own right, with a diverse range of unusual landscapes and features that can keep scientists busy for decades. ESA has chosen to focus on Ganymede, the largest example of an icy moon in our solar system. It is thought to be made of roughly equal measures of rocks and water ice, and is likely to harbour a saltwater ocean beneath its icy crust. For those searching for habitable environments in our solar system, the mantra has always been to follow the water, as the vital solvent for the chemical reactions of life.

Ganymede's surface has a mixture of ancient, dark, cratered surfaces, and brighter water-ice-rich regions of ridges. The biggest feature is a dark plain called Galileo Regio, visible from Earth even through amateur telescopes, and may even have polar caps of water frost.  Furthermore, Ganymede has an extremely tenuous oxygen atmosphere, and is the only moon in our solar system with a magnetic field, probably caused by convection within a liquid iron core.

OSB: How does it compare to Jupiter’s other moons?
LF: To better understand Ganymede, it's important to consider the processes which shaped its evolution and surface features by comparing it to the other Galilean moons: although these four worlds of fire and ice probably had the same origins in the Jovian sub-nebula, their present-day structure is the end of product of aeons of subsequent evolution. Jupiter's immense gravity causes tidal flexing of the moons (strongest at Io, weak or absent at Callisto), providing energy to liquefy the water ice crusts and produce internal activity.

Io is mostly rocky, lacking the water ice of the other satellites but featuring hundreds of active volcanoes. Europa is the smallest of the four, with a smooth geologically-young icy surface overlying a water ocean, heated by the tidal flexing from Jupiter. Ganymede's ocean is likely to be deeper than Europa's, under a thicker ice crust. Callisto is further away and experiences less tidal heating, resulting in an ancient terrain, one of the most highly cratered surfaces in the solar system.

OSB: What do we hope JUICE will find out about it?
LF: JUICE will be the first orbiter of an icy moon, and provide a full global characterisation of its surface composition, geology and structure. An ice-penetrating radar will peer through the icy crust for the first time, providing us with our first access to the water ocean of a Galilean moon. Our key goal is to assess the potential habitability of Ganymede as a representative of a whole class of ‘waterworlds’ which may exist around other stars, building upon the discoveries of habitable environments on the Earth's deep ocean ridges.  So JUICE will be looking for key characteristics of habitability on Ganymede - sources of energy, access to crucial chemical elements, liquid water, and stable conditions over long periods of time.

It's a crucial step in our reconnaissance and exploration of our solar system, and towards answering the question of 'What are the necessary conditions that make a planetary body habitable?’ By comparing the three potentially ocean-bearing Galilean moons, we hope to identify the physical and chemical characteristics driving the evolution of this planetary system.
JUICE will study the extent of Ganymede's ocean, its connection to the deep interior and ice shell; the global distribution and evolution of surface materials, geologic features, and present-day surface activity; and the interaction with the local environment and magnetosphere. In addition, JUICE will explore recent activity and composition on Europa, and characterise Callisto as a remnant of the early Jovian system. Finally, JUICE will be capable of exploring the wider Jovian system, from the complex and dynamic Jovian atmosphere, the magnetosphere, the minor satellites and rings.

OSB: What instruments will be needed to study it?
LF: The proposed JUICE payload has cameras to take images of the icy moon surfaces and swirling Jovian clouds; spectrometers covering ultraviolet, near-infrared and sub-millimetre wavelengths to determine moon compositions and temperatures, winds, composition and cloud characteristics on Jupiter; a magnetometer and plasma instruments to conduct an investigation of Jupiter's magnetosphere; and a laser altimeter, ice-penetrating radar and radio science instrument to probe below the surface of the Galilean moons and through the Jovian cloud decks. 

The payload is just a model right now, and other instruments could be added. All this will be launched on a 5 tonne spacecraft in 2022, with solar arrays to provide power and a large high-gain antenna to return the data to Earth. It will take 7.5 years to reach the giant planet, before going into orbit around Jupiter to conduct an extensive survey of the whole planetary system. Then, in the final phase in 2032, it will enter orbit around Ganymede.

OSB: How are Oxford scientists likely to contribute?
LF: Oxford has a strong heritage of contributing instrumentation and data analysis techniques for outer solar system missions, notably with the near infrared mapping spectrometer (NIMS) on Galileo and the composite infrared spectrometer (CIRS) on Cassini.  We also have a long-term campaign of giant planet studies from ground-based observatories in Hawaii and Chile and space-borne telescopes (Spitzer, Herschel, Hubble). This has allowed us to contribute to the science case for a return mission to Jupiter and its icy moons, identifying the key questions and mysteries left unanswered by previous generations of spacecraft.

Oxford, along with many other UK institutions, will hope to contribute instrumentation to fly to Jupiter to address some of these questions. Involvement with Galileo and Cassini enabled Oxford to build up a rich planetary science group, with a broad range of experience from lab spectroscopy to spacecraft hardware, and from icy moons to gas giant dynamics. This expertise will help us to solve the challenges presented by the JUICE mission.

OSB: What is the next big milestone for the JUICE mission?
LF: Now that the mission has been officially selected by ESA as the L-class mission for 2022, the hard work really begins. Industry will be invited to design and build the spacecraft systems, and an announcement of opportunity will be issued to call for instrument designs. Teams will be assembled to thrash out ideas for instruments that address key scientific questions, all hoping to see their particular design on the launch pad when we lift off for Jupiter in a decade's time.  The final go-ahead for the mission from ESA, known as 'adoption', should come in the next 2-3 years.

Tuesday 1 May 2012

Pythagora's Trousers

At the end of April, Chris North (University of Cardiff, BBC Sky at Night, @chrisenorth) interviewed me for the Pythagoras’ Trousers radio podcast, which was broadcast on Monday April 30th on Radio Cardiff.  We spent 20 minutes discussing the outer solar system, with themes ranging from the formation of the giant planets and why the gas and ice giants appear so different; future missions to explore the giant planets and their icy moons; and professional-amateur collaborations on giant planet storm tracking.  We focussed for a while on future Jupiter missions, including Juno (en route and due to arrive in 2016) and JUICE (the ESA Jupiter Icy Moons Explorer, due to arrive in 2030).

The podcast can be downloaded from the following website.  Here’s their write-up:

Small businesses in Wales and astronomy
On this week’s programme, Rhys talks to Peter King from DPI Limited about job opportunities for science and engineering graduates amongst small businesses in Wales and our STEM Ambassador of the Week is Brij Geerjanan from Tata Steel. Later on, Chris North talks to Leigh Fletcher from the University of Oxford about the outer solar system and Hugh Lang guides us through the night sky throughout May. Finally, this week’s Subject of Science looks at the history of the zip.

Pythagoras’ Trousers is a radio show from the South Wales Networks of theInstitution of Engineering & Technology and Radio Cardiff. Each week, presenter Rhys Phillips takes a look at stories of interest from the worlds of science, technology, engineering and mathematics, bringing these fields to a wider audience and promoting these subject areas to school pupils.
The show is broadcast on Radio Cardiff every Monday evening 8-8:30pm and repeated Tuesday nights 11-11:30pm.