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Where We Might Sample Europa’s Ocean

No one interested in the prospects for life on other worlds should take his or her eyes off Europa for long. We know that its icy surface is geologically active, and that beneath it is a global ocean. While water ice is prominent on the surface, the terrain is also marked by materials produced by impacts or by irradiation. Keep in mind the presence of Io, which ejects material like ionized sulfur and oxygen that, having been swept up in Jupiter’s magnetosphere, eventually reaches Europa. Irradiation can break molecular bonds to produce sulfur dioxide, oxygen and sulfuric acid. And we’re learning that local materials can be revealed by geology.

A case in point is a new paper that looks at infrared data obtained with the adaptive optics system at the Keck Observatory. The work of Mike Brown, Kevin Hand and Patrick Fischer (all at Caltech, where Fischer is a graduate student), suggests that the best place to look for compounds indicative of life would be in the jumbled areas of Europa called chaos terrain. Here we may have materials brought up from the ocean below.

“We have known for a long time that Europa’s fresh icy surface, which is covered with cracks and ridges and transform faults, is the external signature of a vast internal salty ocean,” says Brown, and our imagery of these areas taken by Galileo shows us a shattered landscape, with great ‘rafts’ of ice that have broken, moved and later refrozen. The clear implication is that water from the internal ocean may have risen to the surface as these chaos areas shifted and cracked. And while a direct sampling of Europa’s ocean would be optimal, our best bet for studying its composition for now may well be a lander that can sample frozen deposits.

chaos

Image: On Europa, “chaos terrains” are regions where the icy surface appears to have been broken apart , moved around, and frozen back together. Observations by Caltech graduate student Patrick Fischer and colleagues show that these regions have a composition distinct from the rest of the surface which seems to reflect the composition of the vast ocean under the crust of Europa. Credit: NASA/JPL-Caltech.

Brown and team, whose work has been accepted at The Astrophysical Journal, examined data taken in 2011 using the OSIRIS spectrograph at Keck, which measures spectra at infrared wavelengths. Keck is also able to bring adaptive optics into play to sharply reduce distortions produced by Earth’s atmosphere. Spectra were produced for 1600 different locations on the surface of Europa, then sorted into major groupings using algorithms developed by Fischer. The results were mapped onto surface data produced by the Galileo mission.

The result: Three categories of spectra showing distinct compositions on Europa’s surface. From the paper:

The first component dominates the trailing hemisphere bullseye and the second component dominates the leading hemisphere upper latitudes, consistent with regions previously found to be dominated by irradiation products and water ice, respectively. The third component is geographically associated with large geologic units of chaos, suggesting an endogenous identity. This is the first time that the endogenous hydrate species has been mapped at a global scale.

We knew about Europa’s abundant water ice, and we also expected to find chemicals formed from irradiation. The third grouping, though, being particularly associated with chaos terrain, is intriguing. Here the chemical indicators did not identify any of the salt materials thought to be on Europa. The paper continues:

The spectrum of component 3 is not consistent with linear mixtures of the current spectral library. In particular, the hydrated sulfate minerals previously favored possess distinct spectral features that are not present in the spectrum of component 3, and thus cannot be abundant at large scale. One alternative composition is chloride evaporite deposits, possibly indicating an ocean solute composition dominated by the Na+ and Cl ions.

spectra

Image: Mapping the composition of the surface of Europa has shown that a few large areas have large concentrations of what are thought to be salts. These salts are systematically located in the recently resurfaced “chaos regions,” which are outlined in black. One such region, named Western Powys Regio, has the highest concentration of these materials presumably derived from the internal ocean, and would make an ideal landing location for a Europa surface probe.
Credit: M.E. Brown and P.D. Fischer/Caltech , K.P. Hand/JPL.

The association with chaos areas is significant. Because these spectra map to areas with recent geological activity, they are likely to be native to Europa, and conceivably material related to the internal ocean. In this Caltech news release, Brown speculates that a large amount of ocean water flowing out onto the surface and then evaporating could leave behind salts. As in the Earth’s desert areas, the composition of the salt can tell us about the materials that were dissolved in the water before it evaporated. Brown adds:

“If you had to suggest an area on Europa where ocean water had recently melted through and dumped its chemicals on the surface, this would be it. If we can someday sample and catalog the chemistry found there, we may learn something of what’s happening on the ocean floor of Europa and maybe even find organic compounds, and that would be very exciting.”

So we’re learning where a Europa lander should be able to do the most productive science in relation to astrobiology and the ocean beneath the ice. Keep your eye on the western portion of the area known as Powys Regio, where the Caltech team found the strongest concentrations of local salts. Powys Regio is just south of what appears to be an old impact feature called Tyre. The image below, with the concentric rings of Tyre clearly visible, reminds us that an ocean under a mantle of ice is vulnerable to surface activity and external strikes that would break through the ice and deposit ocean materials within reach of the right kind of lander.

800px-PIA01633_Tyre_impact_structure_Europa

Image: The feature called Tyre, showing signs of an ancient Europan impact. Credit: NASA/JPL-Caltech.

The paper is Fischer, Brown & Hand, “Spatially Resolved Spectroscopy of Europa: The Distinct Spectrum of Large-scale Chaos,” accepted at The Astrophysical Journal (preprint).

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Comments on this entry are closed.

  • Hop David October 29, 2015, 11:36

    Let’s see… From LEO I get 6.3 km/s for trans Jovian injection.

    Europa doesn’t have an atmosphere to speak of so shedding velocity for a soft landing must be accomplished with rockets. I’m getting 9.7 km/s for a soft landing on Europa. I expect that could be mitigated with gravity assists from other moons, though.

    Jupiter has a monster magnetic field and intense radiation belts. The lander would have to be very rad hard.

    I like the idea but I believe it would be a very difficult mission.

  • Andrew LePage October 29, 2015, 13:07

    @Hop David October 29, 2015 at 11:36

    There are potentially easier methods to sample the surface of Europa other than sending a lander. Samples from the purported plumes of Europa could be secured using aerogel collector technology like that successfully used on NASA’s Stardust mission for return to Earth.

    http://www.drewexmachina.com/2014/03/27/a-europa-io-sample-return-mission/

    Even if the Europan plumes prove not to exist, micrometeorite impacts may launch enough material from the surface of Europa to be collected and analyzed – a technique that will be used by SUDA (SUrface Dust Mass Analyzer) and possibly MASPEX (MAss SPectrometer for Planetary EXploration/Europa) instrument to be carried by NASA currently planned Europa mission.

    http://www.drewexmachina.com/2015/05/29/sampling-the-surface-of-europa/

  • Steven Ward October 29, 2015, 15:26

    Hop David, your comment reminds me of a question that I have had for some time in regards to Europa, from what I understand, Europa is tidally locked to Jupiter. I read quite frequently on how much radiation the future orbiter/lander will be subjected to. If the lander was placed on the opposite side or just past the terminator line, would this not shield it from the radiation? Or perhaps its the radiation facing side of Europa that’s more interesting?

  • Paul Gilster October 29, 2015, 16:16

    Steven, the radiation environment around Jupiter is caused by the effects of the magnetosphere, which accelerates solar plasma and produces intense radiation, problematic for any spacecraft in the most dangerous areas. In other words, this radiation is not emanating from the surface of Jupiter, so you couldn’t escape the effect by going past the terminator on Europa. This Wikipedia article has some good info:

    https://en.wikipedia.org/wiki/Magnetosphere_of_Jupiter

  • Alex Tolley October 29, 2015, 16:29

    Rather than soft land, could we use some sort of shock-resistant instrumented ballistic probe? The analyses we want are going to be using mass spec or possibly chromatography to analyze the chemistry. Admittedly the targeting will have to be extremely precise, but we have laser targeted missiles today that can hit with high accuracy, so a rocket guided one instead may be possible?

    If the probe can be slowed to orbital velocity, impact is just 2 km/s. If a ballistic trajectory can be found, them the energy cost of such an approach might be quite low in comparison to a complete Jupiter capture and Europa orbit insertion.

  • John Freeman October 29, 2015, 17:32

    @ AndrekwLepage: Do we need to rely on natural impactors? An artificialimpactor could be sent, and a probe with aerogel collectors coul fly through the plume. A lander would give better preserved samples thougb……

  • Mikhail October 29, 2015, 21:01

    Low-yield nuke seems a nice option to produce enough vapor and possibly debris for orbital sample collector. It could actually fly through the cloud which is way cheaper in terms of required delta V.

  • Andrew LePage October 29, 2015, 21:28

    @John Freeman October 29, 2015 at 17:32

    Relying on natural impactors does make for a less expensive mission (a major plus when trying to get any mission through the approval process). However, if the dust density is below some threshold, it could prove cost effective to use an artificial impactor like that used in NASA’s Deep Impact comet mission. Either way, such mission architectures would be FAR less expensive than a traditional sample return mission employing a lander.

  • Charlie October 30, 2015, 0:51

    Several years ago I had the pleasure of attending a talk on the recovery of the Mercury spacecraft to that Gus Grissom flew in his days as one of the starting Mercury astronauts. As you recall the door of the Mercury spacecraft he was in blew its hatch and the spacecraft sank into the bottom of the Atlantic Ocean. That capsule was recovered from the ocean bottom. A few years ago and brought to the surface and it is in now a museum.

    The point I’m trying to make here is that during the recovery operation which you would think was extremely simple was in fact one of the most complicated things that you can imagine. The fiber-optic cable that was sent down to be attached to the capsule was collapsed and snapped by the pressure of the ocean surrounding it. There was also a large number of other problems, but my point is that a simple things such as attaching a cable to this spacecraft in normal salt water on earth was a stupendous task.

    Everything I read about this Europa probe suggests that it’s going to have to have a cable attached to it, as it drills through the ice such that the transmitting unit on the surface can maintain contact with the submerged probe. If all this ice is grinding and grinding as you would expect it would through motion of the oceans and all that. Wouldn’t it be reasonable to suspect that you would have the cable almost certainly detached from the surface transmitter ? It seems that there does not appear to be any easy way to send a submarine down through the ice into the ocean below and have it keep contact with the mothership above. Doesn’t this seem extremely reasonable to other people?

  • Michael October 30, 2015, 4:27

    If we have a lander with a power source it should be much easier to melt into the surface due to the melting point lowering attributes of the salts allowing us to get beneath the surface.

    As for the radiation belts there are places on the surface of Jupiter’s moons where the radiation can’t get to and that is in cracks that are perpendicular to the radiation belt flows as they will be well protected by the mass of ice.

    @Mikhail October 29, 2015 at 21:01

    ‘Low-yield nuke seems a nice option to produce enough vapor and possibly debris for orbital sample collector. It could actually fly through the cloud which is way cheaper in terms of required delta V.’

    Not only will the device eradiate the surface and create an EMP that could disable the craft the decay radiation will be trapped in the Jovian radiation belts for a significant length of time.

    For me a trip to Ceres would be more fruitful and test a lot of the technologies for a Europa mission in a faster time frame.

  • Michael October 30, 2015, 5:28

    @Hop David October 29, 2015 at 11:36

    Let’s see… From LEO I get 6.3 km/s for trans Jovian injection.

    ‘Jupiter has a monster magnetic field and intense radiation belts. The lander would have to be very rad hard.’

    There is the possibility of using a mag sail in the Jovian system to slow things down a bit and move around the system. I bet there would be science teams around the world that would love to test a mag-sail on a mission like this.

  • Morris The Cat October 30, 2015, 7:12

    Maybe i am being daft but could we not make a lander/probe substantially resistant to radiation? is the radiation there so much greater than that faced by countless probes we have throughout the solar system?

  • ljk October 30, 2015, 9:04

    New Concepts to Explore the Jovian System

    Posted by Van Kane

    2015/10/28 13:04 UTC

    Last year, NASA’s managers invited the European Space Agency (ESA) to propose a small spacecraft to explore the Jovian system. The small craft would be carried to Jupiter by NASA’s own, large Europa multi-flyby spacecraft. This daughter mission could add to the exploration of Europa or study another target.

    ESA has recently posted the results of studies for two possible missions. While these were concept studies and not an actual proposal from ESA to NASA, they give an idea of the possible capabilities and limitations on an ESA contribution.

    Current and in-development missions already will conduct many of the obvious studies for the giant planet’s system. Next year, NASA’s Juno spacecraft will study the Jupiter itself from just a few thousand kilometers above the surface. ESA’s JUICE spacecraft will arrive in the late 2020s to study Jupiter from afar, flyby Europa and Callisto multiple times, and then orbit Ganymede.

    NASA’s Europa Mission (apparently no longer called the Europa Clipper) will flyby Europa 45 times as well as flyby Ganymede and Callisto. These missions will carry suites of extensive and highly capable instruments.

    A small ESA spacecraft would need to find a scientific angle not already taken by its larger cousins.

    Under NASA’s proposal, the American space agency is reserving space and 250 kg of mass to host the European spacecraft. (NASA is also separately reserving mass for the equipment to connect the two spacecraft.)

    Full article here:

    http://www.planetary.org/blogs/guest-blogs/van-kane/1028-new-concepts-to-explore-the-jovian-system.html

  • ljk October 30, 2015, 9:56

    “It’s organic” as one fictional cosmonaut said in the 1984 sequel to 2001: A Space Odyssey in regards to Europa. he may as well have been referring to the dark material along the cracks of that alien moon.

    I and some others less concerned about professional peer pressure and antiquated views of the Sol system have maintained that if you want to find life on Europa, just place a lander along one of those cracks. No need for an expensive and complex robot submersible probe, though of course it would be oh so very cool and useful to eventually have one swimming in Europan waters.

  • TLDR October 30, 2015, 13:15

    If I had my druthers, we’d have sample returns from Europa, Enceladus and Titan. The number of experiments that a space robot can run is limited. On the other hand, a Terran science lab would look at the samples in many different ways.

  • Michael October 30, 2015, 16:47

    @Morris The Cat October 30, 2015 at 7:12

    ‘Maybe i am being daft but could we not make a lander/probe substantially resistant to radiation? is the radiation there so much greater than that faced by countless probes we have throughout the solar system?’

    It is possible but it adds mass which gets expensive. If we can get to the surface quickly and hide in a crack/gully or crater we could reduce the mass needed greatly as the moon would give the physical mass instead.

  • Hop David October 31, 2015, 11:12

    “Everything I read about this Europa probe suggests that it’s going to have to have a cable attached to it, as it drills through the ice such that the transmitting unit on the surface can maintain contact with the submerged probe.”

    (Rereading Paul Gilster’s article…) The article isn’t talking about a probe that penetrates Europa’s crust to reach the liquid ocean below. It is talking about a good place to sample surface ice.

    “If we can get to the surface quickly and hide in a crack/gully or crater”

    I imagine the JPL guys would prefer plateaus to canyons for landing sites. Same goes for regions amenable to exploration with rovers.

    Also it’s desirable to keep line of sight communication with the probe. Canyon walls would tend to block communication with earth.

  • EricSECT October 31, 2015, 17:33

    As much as I am a fan of Europa… seems it would be more productive to Aerogel sample/return a plume of Enceladus. It will take longer and probably be more expensive. But I would peg Enceladus slightly higher on the “most likely to harbor life list” over Europa as well as easier to sample. One no doubt has a saline ocean in contact with rock, with organics and H2 being sprayed out, the other probably has an ocean (but it could be all ice) and of possible high acidity (Io contamination).

  • Charlie October 31, 2015, 20:42

    We hear this all the time; a little off-topic, but still of some pertinence:

    We hear it all the time whenever the arguments are made for space travel and interplanetary commerce: ‘We can mine the asteroids and comets and sell the ores for millions of dollars!’ In reality, these pronouncements tend to underestimate both the astronomical realities and what actual ore extraction costs.

    The meme of space mining has been with us since 1898 when Garritt Serviss penned the story ‘Edison’s Conquest of Mars’.We need better economic reasons for entering interplanetary space, and we will only have these if we look at all aspects of interplanetary economics with a large measure of realism. Dreams will only take us so far, but can also engrain old ways of thinking when new ones are required. Here are the Top Five facts as an astronomer sees them, about what mining activities entail.

    Fact 1: There are not likely to be any ‘ores’ to mine.

    On Earth, elements can become concentrated into ores that can be economically mined. How ore bodies are produced is still something of a mystery. Common ores seem to require volcanism, which means continental drift, or sedimentation (banded iron deposits), or even biological activity (e.g. vanadium). None of these mechanisms are present in asteroidal bodies. Asteroids seem never to have been a part of a primordial body that was massive enough to do more than heat the interior briefly, and separate heavier iron/nickel from lighter silicate-rich material. Chondrites are even more primitive and never experienced much heating, otherwise the delicate organic compounds would have been cooked out of existence.

    Instead, we find asteroids that fall into a few dozen chemical families. You have heard of iron-nickel meteorites, but there are also stony meteorites, carbonaceous chondrites and many other groups. These can sometimes be traced back to a known parent asteroid. For example the “HED” group of meteorites, (howardites, eucrites, and diogenites) are associated with the asteroid Vesta. We even have a few dozen meteorites from Mars! We can even get a general idea where asteroid of different compositions are found in the asteroid belt!

    2015-10-29-1446117792-2862239-AsteroidTypes.jpg
    C-types are rich in carbon compounds, S-types are rich in silicates and M-types are rich in metals like iron and nickel.
    Figure from F. E. DeMeo and B. Carry (Harvard University).

    Fact 2: Most asteroids and recovered meteorites are relatively homogeneous.

    Desirable elements are present at several grams per ton (1 part per million), but distributed throughout the rock. That means that extraction is a complex process requiring grinding the rock to dust and adding the appropriate chemical reaction or other process to extract the desired element. For example on Earth, gold is extracted using a variety of chemical methods depending on the impurities present. At some point, engineers will have to demonstrate how they can take a sample of asteroidal material in the laboratory and extract a useful element or compound from it at the lowest cost. This has not been done yet.

    2015-10-29-1446117842-9223040-StonyMeteorite.jpg
    A typical stony meteorite (Credit: PlanetFacts.org)

    Fact 3: The primary resource in the outer solar system is ice!

    The vast majority of the satellites of the outer planets are either completely composed of ice, or for the larger ones, have a denser silicate core buried under hundreds of kilometers of ice and liquid water. It is cheaper to mine a kilogram of ice in the outer asteroid belt or in comets, than it is to journey into the outer solar system to mine the same kilogram. There is no conceivable reason to transport ice mined in the outer solar system to Mars, the moon or Earth. In fact, Mars and the Moon are already known to have their own stockpiles of minable ice for colonists to use for drinking water and fuel. Comets and some of the asteroids in the outer reaches of the asteroid belt have abundant water that is more easily accessible. It is generally assumed that water-ices will be converted into rocket fuels (e.g. liquefied hydrogen and oxygen) to be used to re-fuel rockets in space at fuel depots near Earth and Mars.

    Fact 4: What happens in Vegas stays in Vegas.

    The expense of mining a ton of rock and rendering it into a few grams of a desired element in space prohibits bringing the processed element back to Earth. There is also no economic value to bringing rocket fuel generated from mined ice back to Earth. Some recent proposals (e.g. Planetary Resources and Deep Space Industries) refer to platinum mining, but the recovery and shipment cost of platinum from space would push the per-gram price of platinum well above the current world market value of $33.00 per gram. The infrastructure needed in space to mine and extract a gram of any element has to be recovered through the pricing of the element when brought to market. There is no way to make elements mined in space competitive with ground-based extraction and pricing. The only known solution that keeps the mining idea viable is that the extracted mineral, compound or element must remain in space! But why mine in space when you can mine on the surface of the moon, Mars, or even an asteroid to extract locally the raw materials to build your habitats?

    Fact 5: Some of the easiest asteroids to reach are in near-earth orbits!

    You don’t have to trek all the way out to the asteroid belt to access useful resources. NASA plans to snag a boulder from the surface of one of these close encounters in the near future in its Asteroid Redirect Mission to be launched in the early-2020s. The boulder will be moved into a lunar orbit, where astronauts will visit it to conduct scientific research and recover samples. Even cooler, it will use the tiny gravity of the ARM spacecraft, acting over many years to actually change the orbit of the asteroid. If this works, similar techniques will be used to redirect asteroids that may be in a collision course with Earth in the far future.

    If we are ever going to make space travel happen, we need to have a far more realistic economic reason for embarking on such an undertaking, and 100-year-old memes are not a very good place to start the discussion.

  • Eniac October 31, 2015, 23:47

    I like the idea of a penetrator. When arriving at high enough speed, it should cut through the ice like butter. Perhaps with a mini-submarine remaining intact at the center of an otherwise solid platinum projectile. Or, with a second probe waiting to enter through the hole that the impactor creates. No bombs needed, the kinetic energy should be plenty. For the impactor, we’d also save the 9.7 km/s that Hop David mentions: dispense with all braking maneuvers and simply plot a collision course directly from trans-Jovian.

    A cable for communications would not be needed. Both water and ice are excellent conductors of sound, just use that to communicate with a surface lander. We might even pick up some whale songs while we are listening. :-)

    Between drilling, melting, and impactor, the impactor seems to me the most realistic approach to getting inside the “ocean”.

    Apropos listening: It seems that none of the craft we have successfully landed on Mars (or anywhere?) were equipped with microphones. What were they thinking???

  • Michael November 1, 2015, 3:18

    @Hop David

    The cracks/gullies on Europa are quite large some km’s in width and stretch for hundreds of km and they are made up of the last material to freeze so making it easier for examination. On Europa the horizon is not that far away anyway so landing on a plateaus versus a much, much lighter mass of a lander would be well worth the occasional comm’s delay to an orbiter.

  • Eniac November 1, 2015, 12:44

    Charlie: Some very good points there. In my view, only high value products like platinum have a chance to be profitable on Earth markets, and only if you can cheaply drop them to Earth. I am not super familiar with the mechanics of atmospheric reentry, but I am pretty sure that a lump of pure platinum, aimed at the right angle, would get down to the surface just fine, where it could then be picked up like those meteorites you mention.

    Using direct reentry, transport to the Earth’s surface is actually pretty cheap. It is how Apollo astronauts returned: With very little fuel, and without bothering to go into Earth orbit, first.

    Of course, you’d have to find “ores” in space that are much better than those on Earth, and I do not believe anyone knows much about that, yet. Those iron/nickel asteroids seem to be so rich in iron/nickel and perhaps platinum group elements that they may be valuable dropped to Earth without any in-space processing, but I do not really know.

    There will be some issues concerning the safety of direct reentry, that could hold up things quite a bit, too.

  • Charlie November 1, 2015, 17:51

    Picking up sample the ice off the surface to obtain a specimen of what might be organic are living material underneath the ice in the supposed oceans there might not be such a great idea as people think it is.

    As everyone completely forgotten all the radiation that that planet is subjected to on a constant basis ? With radiation that intense it’s extremely, extremely likely that organic materials have been sufficiently degradation by that energy deposition that such they would be less representative than you might imagine of what is in the oceans below. At least that’s my opinion

  • Michael November 2, 2015, 10:45

    @Charlie November 1, 2015 at 17:51

    ‘As everyone completely forgotten all the radiation that that planet is subjected to on a constant basis ? With radiation that intense it’s extremely, extremely likely that organic materials have been sufficiently degradation by that energy deposition that such they would be less representative than you might imagine of what is in the oceans below. At least that’s my opinion’

    There are some less hazardous places on the surface if you are in the right spots.

    http://lasp.colorado.edu/~bagenal/3720/CLASS8/EuropaCartoon.jpg

    Here is a more in depth article on the environment.

    ftp://space.mit.edu/pub/plasma/publications/jdr_sittler_europa/jdr_sittler_europa.pdf

    And

    http://people.virginia.edu/~rej/papers03/paranicas02grl.pdf

  • Hop David November 2, 2015, 11:17

    Charlie wrote “On Earth, elements can become concentrated into ores that can be economically mined.”

    Not sure how this pertains to sampling the surface of Europa but I’d like to answer.

    From pages 113 and 114 of Asteroid Mining 101 by John S. Lewis:
    “The first of many profound differences between terrestrial mining technologies and that necessary for mining asteroids lies in Earth’s long history as a thoroughly differentiated and continuously recycled planet. Siderophile (affinity for metallic iron) and chalcophile (affinity for sulfur) elements have been efficiently extracted into Earth’s core, dense ferromagnesian silicates have been concentrated into the mantle, and a low density, volatile-rich residual melt rich in alkali metals, silica, water and other incompatible elements have floated to the top to form the crust, oceans and atmosphere. Many ‘precious’ and ‘strategic’ metals exist in small traces in the crust thanks mainly to the accretion of asteroidal material after the crust was already formed; the vast majoroity of Earth’s content of these elements resides in the core.”

    and near the bottom of page 114:

    “The great virtue of the primitive state of chondrites is that the precious and strategic metals have not be extracted and hidden from view—and from access.”
    http://www.amazon.com/Asteroid-Mining-101-Wealth-Economy/dp/0990584208

    So it is *due* to their primitive state that chondrites can have very rich mineral deposits (relative to earth’s crust).

    Charlie wrote “It is cheaper to mine a kilogram of ice in the outer asteroid belt or in comets, than it is to journey into the outer solar system to mine the same kilogram.”

    No one is talking about near term mining of the outer asteroid belt much less Kuiper Belt objects.

    In his book Lewis talks about Carbonaceous Ivuna near earth asteroids. These can be 40% water by mass. These can be parked in lunar orbit for as little .2 km/s.

    A propellent source high on the slopes of earth’s gravity well would break the exponent in Tsiolkovsky’s rocket equation. Smaller delta V budgets allow higher dry mass fractions. Economic, reusable spacecraft become possible. And with with cheaper space transportation, an asteroid’s rich deposits of platinum group metals and other commodities might become economic.

  • Michael November 3, 2015, 3:52

    I have said this before, if we could harness the power of Jupiter’s magnetic field the jump to the stars would be that much easier. Jupiter’s magnetic field rotates about the planet, at Europa at around 90km/s, if we could catch that magnetic field and use it for power it would be an astonishing amount.

  • Mark November 3, 2015, 14:28

    How much would an impactor / orbiter mission cost? Seems like your best bang for the buck. Take an existing mission and bolt an impactor unit to it. Then image the spectrum of the resulting explosion. Of course if the planet does have life this could be considered an act of war.

    Has anyone given any thought to enabling the use of cheaper solar powered spacecraft at Europa by simply precipitating a catastrophic gravitational collapse within the core of Jupiter so that it ignites internal fusion reactions and becomes a new star? Though the engineering challenges are obvious, there’s nothing in our current understanding of science to preclude such an operation, and there is precedent in the literature.

  • Michael November 3, 2015, 15:48

    @Mark November 3, 2015 at 14:28

    ‘Has anyone given any thought to enabling the use of cheaper solar powered spacecraft at Europa by simply precipitating a catastrophic gravitational collapse within the core of Jupiter so that it ignites internal fusion reactions and becomes a new star? Though the engineering challenges are obvious, there’s nothing in our current understanding of science to preclude such an operation, and there is precedent in the literature.’

    Jupiter neither has the temperature nor pressure to enable H-H fusion, it is simply not massive enough. Any fission/fusion bomb would be destroyed long before it could enable any meaningful H-H compression driven nuclear reactions.

  • ljk November 18, 2015, 11:17

    Even science cannot avoid politics, especially when it needs cash to do something wonderful like explore the global ocean of an alien moon:

    http://arstechnica.com/science/2015/11/attempt-no-landing-there-yeah-right-were-going-to-europa/1/

    To quote:

    It is a nightmare glacier, tormented by the giant of our Solar System ever looming on its horizon.

    Jupiter showers its moon Europa with enough radiation to kill a human in just a few days. Europa must also contend with the massive planet’s powerful tidal forces. The moon literally creaks as Jupiter’s bulk rends its frozen surface in deep crevasses, pushing and pulling the ice upward and downward by tens of meters every few days. And with only a very tenuous atmosphere, it is so very cold: -210 degrees Celsius.

    Yet as forbidding as Europa’s surface may be, just a few kilometers below lies the largest ocean in the known Universe. It dwarfs any on Earth, encircling the entire moon and plunging as far as 100 kilometers deep. The tidal forces that wrench Europa’s icy surface also tug on the core of this ocean, dissipating heat and providing ample energy to warm the ocean.

    Outside of Earth, many astrobiologists say Europa’s vast, dark ocean probably offers the best hope for finding life elsewhere in the Solar System. For these scientists, Europa beckons like the sirens of a Homeric epic.

  • ljk January 5, 2016, 12:22

    A lander for NASA’s Europa mission:

    http://futureplanets.blogspot.ca/2015/12/a-lander-for-nasas-europa-mission.html

    To quote:

    Editorial Thoughts: I of course want to see a lander delivered to the surface of Europa, but I have mixed feelings about the inclusion of a lander on NASA’s first dedicated mission to Europa for two reasons. First, as I will explore in more detail in my next post, adding a lander to the existing Europa mission will push its costs up, perhaps to the $3.5B range when including a launch on the SLS.

    Congress will need to substantially increase the planetary budget to prevent the Europa mission from crowding out the smaller planetary missions that provide balance to the program. While Congress can pass budget laws directing year to year spending, meeting these aggressive goals will require that the President’s Office of Management and Budget (OMB) accepts the new plan and allows NASA to sign the necessary multi-year contracts with its vendors. In the past, OMB has resisted prioritizing the Planetary Science budget to accommodate a Europa mission.

    Second, the driving force behind the expanded mission depends on one Congressman and his continued re-election, his political party’s continued control of Congress, and his health. The alternative approach would be to run the exploration as NASA has run the Mars program by spreading costs out over a sequence of missions. This would be in the vein of the proposed “Ocean Worlds” program currently being shopped to NASA and Congress.

    I expect that in the next few months that we will learn considerably more about the lander’s design and NASA’s plans on how it will fit into its overall planetary program.

  • ljk February 3, 2016, 11:41

    Aiming a bullet at Europa for science:

    http://www.popsci.com/european-scientists-want-to-shoot-this-giant-bullet-at-europa

    Should the Europa mission be split into two launches, one for the orbiter and one for the lander?

    http://spacenews.com/nasa-weighing-dual-launches-of-europa-orbiter-and-lander/

  • ljk February 3, 2016, 11:42

    Europa Clipper budget increase and mission details here:

    http://futureplanets.blogspot.ca/2016/01/europa-budget-bulge.html

  • ljk February 10, 2016, 11:26

    NASA’s Europa mission may not launch until the late 2020s now:

    http://www.space.com/31887-nasa-europa-mission-launch-late-2020s.html

  • ljk February 18, 2016, 14:22