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Jupiter Looms in Mission Plans

We learned in May that Jupiter’s South Equatorial Belt (SEB) had disappeared, an event that still has skywatchers puzzled, though it’s not without precedent. In fact, the SEB fades out every now and then, with recent fadings in 1989, 1993 and 2010, and we can expect an outburst of storms and vortices when the enigmatic belt returns, probably within the next two years, based on historical precedent. All of which puts the spotlight on Juno, a Jupiter mission intended for launch in August of 2011. Juno is all about the giant planet’s core, its magnetic field, its auroras and the amount of water and ammonia in its atmosphere.

Juno’s Jovian Science

Maybe Juno will tell us whether the disappearance of the South Equatorial Belt is the result of ammonia cirrus forming on top and hiding the belt from view. But there is much more to learn. Hydrogen gas deep in Jupiter’s atmosphere is pressed into metallic hydrogen, a fluid that acts like an electrically conducting metal and is thought to be the source of the planet’s intense magnetic field. Juno will, among other things, sample the charged particles and fields near Jupiter’s poles while observing the brightest auroras in the Solar System, caused by charged particles moving into the planet’s atmosphere.

For that matter, does Jupiter actually have a core? Juno should help us find out, pointing to one among two possible formation models. Either a massive planetary core formed early and captured Jupiter’s hydrogen and helium, or an unstable region inside the huge cloud of gas and dust from which our system formed collapsed to create the gas giant. Juno will measure Jupiter’s gravitational and magnetic fields by way of probing its interior structure.

A Hostile Place for Electronics

But what an environment to operate in. Scott Bolton (SwRI), Juno principal investigator, calls the spacecraft “an armored tank going to Jupiter,” a nod toward the protective radiation vault that will house its electronics, protecting these systems from the planet’s vast radiation belts, which circle the planet’s equatorial region and extend past Europa, some 650,000 kilometers from the cloud tops.

“For the 15 months Juno orbits Jupiter, the spacecraft will have to withstand the equivalent of more than 100 million dental X-rays,” said Bill McAlpine, Juno’s radiation control manager, based at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “In the same way human beings need to protect their organs during an X-ray exam, we have to protect Juno’s brain and heart.”

All that radiation is why a future human presence on a place like Europa is so deeply problematic. For Juno, Lockheed Martin Space Systems built a radiation vault out of titanium, each wall measuring close to a square meter in area, a centimeter thick and massing 18 kilograms each. Inside go the spacecraft’s command and data handling box, power and data distribution unit and numerous other electronic assemblies, with a total mass of about 200 kilograms.

Image: Juno’s specially designed radiation vault protects the spacecraft’s electronic brain and heart from Jupiter’s harsh radiation environment. The vault will dramatically slow down the aging effect radiation has on the electronics for the duration of the mission. The image was taken on June 14, 2010, as Juno was being assembled in a clean room at Lockheed Martin Space Systems, Denver. Credit: NASA/JPL-Caltech/LMSS.

It’s going to be fascinating to see how this assembly does, but the Juno team also plans an orbit around Jupiter’s poles to lower the amount of time spent in the worst of the radiation around its equator. JPL has tested the vault in a high radiation environment, a lead-lined testing unit in which spacecraft parts were subjected to gamma rays from radioactive cobalt pellets. More tests await when the spacecraft is completely assembled — the vault is already on Juno’s propulsion module, with complete assembly to be accomplished next spring.

Future Mission to Ganymede and Europa?

Meanwhile, we can forget the image of the team in spacesuits drilling through Europa’s ice. This is one hostile environment for living beings as well as electronics, and unless we find breakthroughs in lightweight radiation shielding, chances are future Europa investigations will have to proceed with our machine proxies. Such proxies would be part of the proposed Europa Jupiter System Mission (EJSM), an international effort involving a Europan orbiter from NASA and a Ganymede orbiter built by the European Space Agency. The two craft would study both moons and return data on the entire Jovian system.

Can it be done? The mission is certainly feasible and it’s a candidate for a flagship mission. But Europa and Mars may conflict at a time when a major Mars sample return effort is also under consideration. We might be able to fund both missions, at the expense of a host of smaller yet worthwhile efforts, but we won’t know how the committee drawing up NASA’s mission goals (for the National Research Council’s Planetary Science Decadal Survey, 2013-2022) will come down on the matter until it makes its draft recommendations in late September.

My guess: We’ll get Europa and, depending on ESA’s decisions, Ganymede as well at the expense of the incredibly complex Mars sample return, a choice that will leave many unhappy, and one that highlights the steep financial constraints we labor under. But it will leave open the possibility of funding much less expensive Discovery-class and New Frontiers-class missions like Juno and New Horizons at the same time we explore Europa and Ganymede.


Comments on this entry are closed.

  • Eniac July 15, 2010, 17:44

    JPL has tested the vault in a high radiation environment, a lead-lined testing unit in which spacecraft parts were subjected to gamma rays from radioactive cobalt pellets.

    In my understanding the actual radiation is charged particles: alpha and beta, not gamma. The penetration properties and effects of these kinds of radiation are quite different, so how can tests with gamma rays be meaningful?

  • James M. Essig July 15, 2010, 18:56

    Hi Folks;

    A really massive ship perhaps including a mini-magnetosphere produced by strong permanent magnets or by efficient electromagnets might permit human excursions into the intense radiation zones around the gas giant planets and their moons. The space craft would need to have enough crew compartment shielding inorder to protect against 1,000 MeV to 10,000 MeV x-rays generated by the solar cosmic rays but since the crew quarters of modern nuclear powered submarines are adequately shielded against nuclear fission products which can have energies in the tens of MeV range, for sufficiently space large craft, the shielding problem should be adequately addressable.

    We might yet see large mining operations within the proximately of the Gas Giant planets and perhaps if we can learn how to do proton fission such as that conjectured about within the science fiction concept of the quark bomb by which the quark’s binding energy and relativistic energy is released by proton fission with a yield of about 0.99 M[C EXP 2], the huge stores of hydrogen present within the Gas Giants can power high gamma factor manned starship for billions of years to follow.

    Whether there could there exist hidden energy or hidden QCD variable types of energy within low atomic number nuclei that we have not learned to harness not to mention detect as of yet, wherein the yield of associated nuclear or sub-nuclear reactions, would be equal to A{M [C EXP 2]} where A is greater than unity, and perhaps much more so, is anyones guess. But one thing is certain, we infact do have nuclear fusion fuel locked up within the Gas Giants, and so any radiation shielded manned infrastructures set up in the environments of the Gas Giants might be very usefull.

    The first steps in designing such infrastructures will involve the subject unmanned probes to the Jovian and Saturnian systems and to their moons. The knowledge gained in pushing the current limits of technology to adequately harden these probes electronics against radiation will be valuable.

  • NS July 16, 2010, 3:35

    Picking space missions must be like being the producer in “A Chorus Line”:

    “Every one of you is terrific. I’d like to hire all of you but I can’t.”

    Then he has to send most of the dancers away.

  • Scott G July 16, 2010, 11:04

    Regarding the future missions: If our budget constraints are such that we have to choose between a Europa orbiter and a Mars sample-return mission, I’d really hope that the former would win out.

    It’s clear that Europa has the potential to harbor a LARGE habitable environment (as in a globe-spanning ocean equivalent in size to all of Earth’s oceans combined). Thus, before we can get an ice-penetrating lander there (which is what we really want), we have to better characterize Europa’s surface and surrounding environment — information that can only be provided by such an orbiter.

    Although Mars may also presently have habitable environments, I think what we really want to do there is to send humans there. I don’t see how a sample-return mission is an appropriate step toward that goal. We already have robotic probes on Mars that can bore into rocks and study them on site. I think this mission only arose because back in the 90’s NASA decided to lay out a baby-step approach to sending humans to Mars — a path which would ever-so-slowly increase the complexity of missions before people would arrive. To me, that’s not the way to go; I think the money would be much better spent paving the way to a Europa lander, which is exactly what the Europa orbiter mission would do.

  • Mike Prather July 16, 2010, 15:10

    Wasn’t it proposed at some point that regardless of whether Jupiter has a rocky core or not, the center is composed (or at least surrounded) by a layer of compressed carbon, then whatever lighter elements up to the liquid metallic hydrogen layer? Any organic molecules falling to the core would be broken down by the pressure and presumably would stratify. Does hydrogen compress into a denser substance than carbon would at those pressures – into a kind of “light” neutron matter?

  • philw1776 July 17, 2010, 10:31

    Scott G called it right. The Mars mission was based on the old step to a manned mission paradigm and offers less promise of new discovery than a Europa mission into the more unknown. At Europa we could learn more about the fascinating ice shell, thickness, etc. We already have ground truth info on Mars soil and excellent orbital spectral coverage. Not to say there’s much more to do but with limited $ let’s spend some away from Mars.

    I admit to being pessimistic about NASA’s space exploration future. The space indifferent public sees NASA Administrator statements about the priority of outreach to Muslim countries and becomes convinced that NASA is not serious or even about space exploration. While I support the Obama Administration’s shift to commercial private company LEO operations, I wonder is there a real political commitment to funding space science, now that manned exploration has been de-funded and the Shuttle being phased out?

  • Mike July 17, 2010, 13:56

    To philw1776, yes if forced to choose I would agree that the Europa mission is the better choice. Also please let’s not criticize Charles Bolden for the orders he receives from his boss.Two years after voting for Obama I must admit that I have developed some serious doubts about his commitment to NASA and to America as well.

  • James M. Essig July 17, 2010, 18:46

    Hi philw1776 and Mike;

    I share your disappointment with Obama’s seemingly lack of initiative when it comes to manned space exploration. I remember how we were supposed to land men on Mars during the 1980s while the Apollo Program was going full swing, how under Reagan, a bold thinking of going to Mars has circulated, and then under President George W. Bush, it was back to Mars again and to the Moon by 2020.

    Now not to state the above obviousness, but it seems like we are in a pepetual state of ever starting over again.

    A trip to Europa would indeed by cool, and I am encouraged regarding the plans to send humans to an asteriod which will cause us to develop truely interplanetary manned space travel systems.

    As for the commercials regarding LEO, a friend of mine, and past contributer of comments to Tau Zero Centauri Dreams, Forrest, suggested to me that just as computer software is jealously gaurded in terms of know-how each time a new application is released for sale, perhaps the commercials will have a competitive feeding frenzy regarding the development of LEO crew insertion technologies.

    Eventually, I think the mining of asteriods with all of the potentially precious metals and rare isotopes they seem to contain, at least in many cases, is going to result in a large scale effort to mine them. The commercials will no doubt step in and; just as say we in the States have a powerfull Navy and Coast Gaurd to protect our nearby by off shore assets, we will need a space based security force to protect our interests with in the Asteroid belt, on the Moon, on Mars, and elsewhere.

    Not to taut the militarization of space, rather the point being is that once resources are actively saught after within interplanetary space, a whole civil infrastructure will need to be set up to support the mining process.

    Thus, NASA can perhaps focus more on deep interplanetary space manned missions and ultimately manned missions to other star systems.

    In the mean time, it is up to us practicioners of Tau Zero to help keep the flame lit in terms of advocacy for manned interstellar travel initiatives, and for those who are working on Project Icarus, to continue approaching their ground breaking applied and theoretical propulsion physics and engineering which ever abundant enthusiasm.

    I will thus conclude by stating “Ad Astra Incrementis”.

  • philw1776 July 20, 2010, 10:45

    @Mike: I am not criticizing Bodden.

    In my favorite universe, commercial interests would innovate with private capital and NASA would then purchase the best commercial solutions for manned space transportation, etc. instead of funding massive rocket development projects that overspend and underperform, e.g. X-33 hangar queen, ISS and Constellation’s “The Stick”. My approach is what made avaition succeed wildly thru the decades via private investment and innovation and the govt NASA approach produced 40 years of committee compromise govt jobs program stagnation post-Apollo.

    Let NASA run space exploration programs like Kepler, WISE and Europa missions.

  • ljk November 6, 2010, 11:07

    So I’m reading the latest Friday installment of Bob Parks What’s New here:


    When I come across this:

    Friday, November 5, 2010


    I was appalled to read in this week’s Nature that the Juno mission to study how Jupiter’s powerful magnetic field is generated, will carry a fragment of bone from Galileos earthly remains. Do the instigators of this foolishness imagine that relics of scientific martyrs, like bones of saints, will somehow confer protection on the spacecraft in the harrowing Jovian environment? To compound my irritation, the information was in a Nature editorial applauding the plan as, “a gesture that would add emotional energy to the mission and remind the public that science is fundamentally a human endeavor.” All too human, it would seem; belief in miraculous cures wrought by fragments of the remains of saints has persisted for 2000 years. The editors confusion of metaphor and fact continues to the end. “The Juno mission will skim just 4,800 kilometres above Jupiter. Galileo just might enjoy a closer look.”

    Now while I think Parks has gotten carried away about this whole relics business, I have to wonder how wise it is to send an actual piece of the famous Italian astronomer into space with no hope of recovery or preservation, seeing as there is only so much of the man to go around.

    And why is this the first I have heard about this? And how is it that NASA, which normally makes such a big deal about anything outside the normal range of items for passage on one of their space probes has now three times sent up human remains aboard a vessel while passing on something more substantial such as an information package about our species?

    The other two missions with human remains was Lunar Prospector impacting the Moon with Eugene Shoemaker’s ashes and New Horizons with some of Clyde Tombaugh’s ashes sailing past Pluto into the galaxy.

    Does anyone know any more about the Galileo-Juno story?

    Here is the Nature editorial online:


  • ljk April 17, 2011, 15:04

    Solar Powered Jupiter bound JUNO lands at Kennedy Space Center for blastoff

    by Ken Kremer on April 17, 2011

    The Juno spacecraft passes in front of Jupiter in this artist’s depiction.
    Juno, the second mission in NASA’s New Frontiers program, is solar powered
    and will blast off for the largest planet in our solar system in August 2011 and investigate the origin and evolution of Jupiter. Credit: NASA/JPL-Caltech

    Juno, NASA’s next big mission bound for the outer planets, has arrived at the Kennedy Space Center to kick off the final leg of launch preparations in anticipation of blastoff for Jupiter this summer.

    The huge solar-powered Juno spacecraft will skim to within 4800 kilometers (3000 miles) of the cloud tops of Jupiter to study the origin and evolution of our solar system’s largest planet. Understanding the mechanism of how Jupiter formed will lead to a better understanding of the origin of planetary systems around other stars throughout our galaxy.

    Juno will be spinning like a windmill as it fly’s in a highly elliptical polar orbit and investigates the gas giant’s origins, structure, atmosphere and magnetosphere with a suite of nine science instruments.

    Full article here:


  • ljk August 4, 2011, 9:14

    So instead of a piece of Galileo’s remains, the Juno probe will be carrying to Jupiter three little LEGO figures of the top two Roman deities and the famous Italian astronomer himself:


    Along with a commemorative plaque dedicated to Galileo and a reproduction of his notebook entry where he found the four largest moons of Jupiter in 1610:


    Enjoy viewing them now, because they will be gone in the depths of the gas giant planet sometime in 2017.