Back To Jupiter…!

NASA has chosen its next “flagship” (translation: mega-expensive and complicated) mission, and it has decided to go with a big mission to Jupiter and its moons called “The Europa Jupiter System Mission” , which it will run in partnership with the European Space Agency.

(I know what you’re thinking, “That’s a rubbish name for a mission!” but stop worrying, it’s just a working name for it for now, “EJSM” will almost certainly be given a scientist’s name long before it launches.)

The announcement was made yesterday, and it was met with a mixture of celebration and disappointment, because there was something of a competition going on between two teams of scientists, with one team passionate about returning to Jupiter with a state-of-the-art probe to look at Jupiter and its fascinating moons with the hi-tech kit we have available now, and another team just as passionate about returning to Saturn and looking at its huge moon Titan in more detail, following on from the fantastically successful Cassini mission. In the end, NASA went for a Jupiter mission as the next definite mission, but also said that the  Titan mission was a candidate for the next major mission after that, and development work on it should and would continue.

Before looking at this in more personal terms, here’s NASA Press Release from yesterday, in case you missed it:

 

At a meeting in Washington last week, National Aeronautics and Space Administration and European Space Agency officials decided to continue pursuing studies of a mission to Jupiter and its four largest moons, and to plan for another potential mission to visit Saturn’s largest moon Titan and Enceladus.

Both of these proposed missions are grand endeavors that set the stage for future planetary science research. These outer planet flagship missions could eventually answer questions about how our solar system formed and whether life exists elsewhere in the universe.

The missions, called the Europa Jupiter System Mission and the Titan Saturn System Mission, are the result of NASA and ESA merging their separate mission concepts. NASA originally studied four mission concepts during 2007, which were narrowed down to two proposals in 2008. One finalist was a Europa Orbiter to explore that icy moon of Jupiter and its subsurface water ocean. The other was a Titan Orbiter to visit the Saturn moon. Independently, in 2007, ESA also initiated a competition to select its flagship mission for the Cosmic Vision 2015-2025 slot of the ESA scientific programme. Two finalists, called Laplace and Tandem, were selected by ESA for further study. Laplace was a set of spacecraft to orbit Jupiter and eventually orbit and land on Europa. Tandem was a set of spacecraft intended to orbit Titan and explore its surface, after also exploring the surface of Saturn’s moon Enceladus.

NASA and ESA engineers and scientists carefully studied both potential missions in preparation for last week’s meeting. Based on these and other studies as well as stringent independent assessment reviews, NASA and ESA agreed that the Europa Jupiter System Mission, called Laplace in Europe, was the most technically feasible to do first. However, ESA’s Solar System Working Group concluded the scientific merits of this mission and a Titan Saturn System Mission could not be separated. The group recommended, and NASA agreed, that both missions should move forward for further study and implementation.

“The decision means a win, win situation for all parties involved,” said Ed Weiler, associate administrator for NASA’s Science Mission Directorate in Washington. “Although the Jupiter system mission has been chosen to proceed to an earlier flight opportunity, a Saturn system mission clearly remains a high priority for the science community.”

Both agencies will need to undertake several more steps and detailed studies before officially moving forward.

“This joint endeavour is a wonderful new exploration challenge and will be a landmark of 21st Century planetary science,” said David Southwood, ESA Director of Science and Robotic Exploration. “What I am especially sure of is that the cooperation across the Atlantic that we have had so far and we see in the future, between America and Europe, NASA and ESA, and in our respective science communities is absolutely right. Let’s get to work.”

New Exploration Challenges at Jupiter and Saturn

The Europa Jupiter System Mission would use two robotic orbiters to conduct unprecedentedly detailed studies of the giant gaseous planet Jupiter and its moons Io, Europa, Ganymede and Callisto. NASA would build one orbiter, initially named Jupiter Europa. ESA would build the other orbiter, initially named Jupiter Ganymede. The probes would launch in 2020 on two separate launch vehicles from different launch sites. The orbiters would reach the Jupiter system in 2026 and spend at least three years conducting research.

Europa has a surface of ice, and scientists theorize it has an ocean of water beneath that could provide a home for living things. Ganymede, the largest moon in the solar system, is the only moon known to have its own internally generated magnetic field and is suspected to have a deep undersurface water ocean. Scientists long have sought to understand the causes of the magnetic field. Callisto’s surface is extremely heavily cratered and ancient, providing a clear indication of a record of events from the early history of the Solar System. Finally, Io is the most volcanically active body in the solar system.

The orbiters would spend nearly a year orbiting Europa and Ganymede. NASA’s probe would investigate whether Europa might harbor life, and ESA’s spacecraft would orbit Ganymede to conduct investigations of the surface and interior of this satellite, to better understand the formation and evolution of the Jovian system.

The Titan Saturn System Mission would consist of a NASA orbiter and an ESA lander and research balloon. The complex mission faces several technical challenges requiring significant study and technology development. NASA will continue studying and developing those technologies. Future work also will provide important input into the next Planetary Science Decadal Survey by the National Research Council of the U.S. National Academy of Sciences, which will serve as a roadmap for new NASA planetary missions to begin after 2013. On the European side, the interested community of scientists will have to re-submit the Titan mission at the next opportunity for mission proposals in the Cosmic Vision programme in the years to come.

NASA’s Jet Propulsion Laboratory in Pasadena, California, will manage NASA’s contributions to the projects for NASA’s Science Mission Directorate in Washington. ESA’s Directorate of Science and Robotic Exploration will manage the European contribution to the Jupiter mission.

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So, cutting a long story short, what are we actually talking about here?

Well, in 2020 – about the same time NASA is planning to send astronauts Back To The Moon – two rockets will blast off, from different sites, each one carrying a spaceproeb bound for Jupiter. Six years later the probes would enter the Jovian system and go into orbit around its Galilean satellites, Io, Ganymede, Europa and Callisto, paying particular attention to two of those moons, namely Europa and Ganymede. They’d also, of course, study and photograph the other two Galileans, and the planet Jupiter itself, too. The primary mission would last three years, but obviously – as has been the case with every space mission for the past decade or so – they’d be hoping for, and confident of, having their mission extended, allowing more science to be returned.

So, what’s the appeal of the Jovian System? Why have Europa and Ganymede beaten Titan in this competition?

Well, basically, it comes down to one word – LIFE. “The Hunt For Life” is now one of NASA’s driving forces, and the discovery of life on another body in our solar system now has to be the Holy Grail of 21st century science. We might just wrap our evolved monkey paw fingers around that Grail by exploring the largest moons of Jupiter, because scientists are now pretty confident that both Ganymede and Europa have “subsurface oceans” – oceans of water beneath their surfaces. If that’s true, then there’s a very real possibility that given the right conditions in those oceans – heat and light from the Sun, nutrients of some kind, etc – life might exist in them. Probably not very advanced life… not whales or sharks or even fish, more like krill or plankton, or swaying, wavy fronds of alien plants, something like that – but life nonetheless.

How big are these moons? Well, let’s look at a picture showing them to scale, with Earth and our own Moon…

 

 

 

(Note: that’s a crop of a HUGE brilliant image I found on the internet a while ago, I use it a lot in my Outreach talks and you can find the full size version here.)

Ganymede is the largest moon in the whole solar system, and is not an awful lot smaller than the planet Mars, if you look at the picture above. It certainly dwarfs Earth’s own Moon. It is a huge ball of ice and rock that looks like a ball of frozen coffee, or Coke. Many planetary scientists are fascinated by Ganymede because of its size and because of the features visible on its surface, features like this…

… and these…

Ganymede is a world of grooves and ridges, craters and pits. It has really, really taken a battering over time. Any 21st century probe going there will take breathtaking images of spectacularly-fractured landscapes. I can’t wait to see new, close-up pictures of its surface! (But I know I’ll have to, as the probe won’t start snapping away until 2026! Eek! I’ll be 61! 61!!!!!!)

But as interesting as Ganymede is, the star of the 2020 mission would undoubtedly be Europa… and it’s the reason why I’ve always been a supporter of a Jupiter-bound mission instead of a Saturn/Titan follower.

Now, don’t get me wrong; I love the Saturn system, and I ove Titan too. What’s not to love about a planet-sized satellite that has its own atmosphere, coastlines, lakes and maybe ice volcanoes, too? But Titan is, well, it’s a smoggy, chemical-spill of a world, and it just seems designed to be as awkward as possible for scientists to study it in any detail. True, the proposed Titan mission sounds thrilling – who wouldn’t be thrilled to the point of blacking-out by the prospect of seeing pictures from a probe that has just splash-landed in one of Titan’s methane lakes, or from a balloon that is drifting over Titan’s plains – but that sounds like a very, very tough challenge to me. It will happen one day, I’m sure, but maybe not for another three decades… and I can’t wait that long!

But Europa…

Europa is one of my favourite worlds in the solar system. It’s captivated and fascinated me ever since I saw those first fuzzy Voyager images of it back in the days of Charlie’s Angels. (Oops, showing my age now!) We now know that Europa is an Antarctic World, a world of awe-inspiring topography. It has icebergs and ice cliffs; grooves and channels; crevices and crevasses. It has features on its mottled, fractured, colour-spattered surface like these…

This is one of the highest resolution views we have of Europa, showing ice cliffs towering over a vast, icy plain…

And those images, which are pretty good, were taken with old technology, cameras nowhere near as good as the kit we have today! Just imagine the stunning images we’ll see when EJSM starts taking pictures… we’ll zoom in on those jagged edged icebergs… see right into the fractures and pits and grooves… catch sunlight glinting off the vast ice plains… see Jupiter looming over Europa’s horizon, just as it’s been shown in space art for all these years…

Of course, these pictures are all a long, long way ahead. There’ll be no pictures until 2026, and that’s only if the mission goes according to plan and there are no engineering/budgetary/political problems. But even though this mission is so far in the future we almost need the Tardis to see it, it’s still inspiring and exciting to imagine the wonders we’ll see. – and wonder what kind of world we’ll all be living in then. As I said, I’ll be 61… how badly will Earth and mankind have been affected by global warming and economic hardship? What will the political situation be? Will China already have beaten the US to the Moon, and be in the process of training astronauts for a manned expedition to Mars? Will we have the first picture of an Earth-like extrasolar planet? Will we have detected a signal from another civilisation from deep space?

Roll on 2026!