Cassini update

NASA--

These raw, unprocessed images of Saturn's moons Enceladus and Tethys were taken on April 14, 2012, by NASA's Cassini spacecraft.

Cassini flew by Enceladus at an altitude of about 46 miles (74 kilometers). This flyby was designed primarily for the ion and neutral mass spectrometer to analyze, or "taste," the composition of the moon's south polar plume as the spacecraft flew through it. Cassini's path took it along the length of Baghdad Sulcus, one of Enceladus' "tiger stripe" fractures from which jets of water ice, water vapor and organic compounds spray into space. At this time, Baghdad Sulcus is in darkness, but that was not an obstacle for another instrument, the composite infrared spectrometer, which can see features by their surface temperatures and which also took measurements during this flyby.

As soon as daylight passed into the spacecraft's remote sensing instruments' line of sight, Cassini's cameras acquired images of the surface. The wide-angle-camera image included in the new batch, taken from around the time of closest approach, has some smearing from the movement of the spacecraft during the exposure, but still shows the surface in vivid detail.

Cassini's cameras also imaged Enceladus' south polar plume at a high phase angle as the satellite appeared as a thin crescent and the plume was backlit.

After the Enceladus encounter, Cassini passed the moon Tethys with a closest approach distance of about 5,700 miles (9,100 kilometers). This was Cassini's best imaging encounter with Tethys since a targeted encounter in September 2005. The 2005 encounter, with a closest approach distance of about 930 miles (1,500 kilometers), provided the images of Tethys with the best resolution and captured views of the side of Tethys that faces Saturn in its orbit. This new encounter examined the opposite side of Tethys, providing some of the highest-resolution images of the side that faces away from Saturn. Cassini acquired a 22-frame mosaic of this side, which features the large impact basin named Odysseus. Scientists will use these new data in conjunction with images from previous encounters to create digital elevation maps of the moon's surface.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory in Pasadena manages the mission for the agency's Science Mission Directorate in Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations team is based at the Space Science Institute in Boulder, Colo. JPL is a division of Caltech.

Cassini flies through Enceladus plumes

This happened yesterday, no report yet on what they found. For those unfamiliar with the Tiger Stripes, it's basically a 16 gigawatt power source (like, large enough to power Los Angeles) at the south pole of Saturn's moon Enceladus, where no such thing should be.
Meanwhile, I'm looking at this photo from December 2009. Several of you have already made the observation, but this particular photo kind of drives the point home. I'm not typically one to see random shapes in things and assume intelligent design, but, really this just doesn't seem like a naturally occurring thing.

NASA--
Less than three weeks after its last visit to the Saturnian moon Enceladus, NASA’s Cassini spacecraft returns for an encore. At closest approach on April 14, the spacecraft will be just as low over the moon’s south polar region as it was on March 27 -- 46 miles, or 74 kilometers.

Like the last, this latest flyby is mainly designed for Cassini’s ion and neutral mass spectrometer, which will “taste” the particles in the curious jets spraying from the moon’s south polar region. Combined with the March 27 flyby and a similar flyby on Oct. 1, 2011, this close encounter will provide a sense of the jets’ three-dimensional structure and help determine how much they change over time.

On Cassini’s outbound leg, the spacecraft will pass by another Saturnian moon, Tethys, at a distance of about 6,000 miles (9,000 kilometers). The composite infrared spectrometer will look for patterns in Tethys’ thermal signature. Other instruments will study the moon’s composition and geology. The imaging cameras are expected to obtain new views of Enceladus and Tethys.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate in Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL.

For more information about the Cassini-Huygens mission visit: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov/ .

Going the distance

Scientific American this month has a very good article on some possibilities for NASA's manned space exploration program, written by two scientists involved in robotic deep-space exploration.

They proposed using a combination of the SLS chemical rockets or Delta IV heavy lift and Hall-effect ion drive spaceships to explore the moon, near-earth asteroids, Mars and Phobos. The argument for exploring near-earth asteroids was as a stepping stone for Mars and Phobos, and they were specifically looking at NEO 2008 EV5.

2008 EV5 follows a slightly oblique orbit very similar to earth's, and oscillates from about 1 AU (the distance from the sun to the earth) and 2 AU, at least in the immediate future. Mars at opposition is only about 0.5 AU from earth. My admittedly limited understanding of Hohmann transfer orbits is that a trip to 2008 EV5 or an earth-Trojan should take longer than a trip to Mars. Given that 2008 EV5 is only about 400 meters across, I must confess that I am at a loss to understand the wisdom of establishing 2008 EV5 as a waypoint to Mars. This is either a failing of my own understanding of how one navigates between two objects in different parts of the same orbit (very likely), or else NASA has other reasons for prioritizing a trip to 2008 EV5. My guess is that both are true; ie, I'm misunderstanding the geometry of a same-orbit Hohmann transfer, and NASA has more need of landing on 2008 EV5 than as a test-run for Phobos. My completely uneducated guess is that either NASA is more freaked out about near-earth asteroids than they let on, or that they want congress to think that they're more freaked out about near-earth asteroids than they let on. I lean toward the latter; perhaps at some point I'll bother to post my very own patented conspiracy theory on the subject. Anyway--

Based on the SciAm article and some of the recent posts here on candidates for outmigration, I created a graphic tonight to illustrate the relative distances of the different candidates being discussed. The planets, asteroids and moons themselves are not drawn even close to scale, but the relative distances between them is mostly right. The only exception to this is the distance between the earth and the moon, which is actually so small on the scale of the drawing that it could not be correctly shown at all. Also, the distances between Jupiter and her moons is completely erroneous, I simply included the Galilean moons to illustrate that the body depicted was in fact Jupiter.

1. The moon, and also the L4 and L5 Lagrangian orbits

2. Near-earth asteroid 2008 EV5, and also the earth-Trojans

3. Mars and Phobos

4. Ceres

5. Jupiter and Europa, Callisto and Ganymede

6. Saturn and Enceladus

It becomes apparent that Enceladus, intriguing though it is, is very, very far away. For a new home for our species, Ceres starts looking better all the time.

Europa back in the game

NASA announced today the presence of enormous salt-water lakes only several kilometers below the surface ice of Jupiter's moon Europa. From the standpoint of colonization (and also incidentally exobiology), this is vastly preferable to the ocean of salt-water which also exists on Europa, but at some 100 kilometers below the surface ice. This puts Europa back in the running as a plausible candidate for outmigration, and possibly even in the top tier.

With this data, the three best candidates for a permanent and self-sustaining colony are, arguably, Ceres, Europa and Enceladus.

Saturn's moon Enceladus is in some ways the most appealing, but by far the least accessible. At 1.5 BILLION kilometers, it is more than twice the distance to Jupiter/Europa, and six times the distance to Ceres. And it is the smallest of the three candidates. But essentially limitless supplies of water and energy are relatively accessible to anyone living on the surface, and from the standpoint of self-sustainability that's huge.

Europa now meets most of the same criteria, is six times larger than Enceladus (and just a bit smaller than our own moon), and is much closer. The biggest drawback with Europa is still the very high amounts of ionizing radiation from Jupiter that would be experienced on the surface. Burrowing under the ice would provide shielding, but you have to get down there first. It is also possible that we could use another of the Galilean moons such as Callisto as a base-camp while drilling down to to the Europan lakes.

Dwarf planet Ceres is practically in our own backyard, and about twice the size of Enceladus. It too is covered with water ice over a salt-water ocean, but we don't know yet how thick that ice-mantle is. When the Dawn spacecraft arrives there in 2015 we'll know a lot more. Ceres receives ample sunlight for solar power, so even if there were no geothermal energy such as on Europa, or whatever-the-hell is generating 16 gigawatts of energy on Enceladus, it could probably support a substantial colony even if the surface ice had to be melted for water. At this time, I'm inclined to think that Ceres may be our best shot at getting a permanent and self-sustaining colony established quickly, but we'll know a lot more once the Dawn spacecraft starts sending back data.

Many people have speculated that Ceres would be an important stepping-stone for colonization of the outer planets, but she may prove to be a critical destination in her own right.

Fortuna Rota

In an earlier post about outmigration, I suggested that a classic Stanford torus space station design could be landed onto the surface of Enceladus in such a way that it would spin like a top, generating artificial gravity for its inhabitants.

A few of you have requested that I elaborate a bit on this idea, but I really don't have a lot to elaborate with. The research for a Stanford torus in space has been done exhaustively. In order to effectively mimic earth's gravity, a Stanford torus is a 1.8 km diameter ring turning at one revolution per minute. A torus this size could provide sustainable habitat for some 10,000 people.

Enceladus has a surface gravity of 0.011% of earth's, meaning something as small as a human would be essentially weightless, but gyroscope nearly 2 kilometers in diameter would presumably have enough mass to keep it "on the ground". The surface of Enceladus is fairly featureless ice, so creating a more or less frictionless stylus for the torus to pivot on should be manageable.

Enceladus has relatively vast resources of fairly accessible seawater and heat energy, although we don't yet know what the source of that energy is. So, that's my idea about putting a torus colony on Enceladus.

Discuss.

;)

Tiger, tiger, burning steadily

The above is a raw, unprocessed photo from the Cassini flyby of Enceladus on Saturday. No data yet on the actual surface temperatures or energy outputs from the Tiger Stripes, but it is clear from this and other photos from this series that whatever the energy source is, it has not diminished significantly.

Curiouser, and curiouser.

Enceladus, Revisited

Tomorrow is a very important day.

Around 1400 UTC tomorrow (0700 PDT) NASAs Cassini spacecraft will do a flyby of the south pole of Enceladus, at an altitude of 99 km (62 miles). This is the first close flyby of Enceladus since early March 2011.

At that time we learned that the Tiger Stripes on the south pole of Enceladus were being heated by an energy source of some 15.8 gigawatts. 1.4 gigawatts is the absolute maximum Enceladus should be able to generate, for a matter of a few short seconds, if all of her potential geothermal and radioactive energy were concentrated into the same place at the same time. Tomorrow we will learn if the Tiger Stripes have cooled, or if they are maintaining this heat output at a consistent (or increasing) rate. All evidence so far indicates that the heat signature is not decreasing.

Tomorrow we'll know for sure. And things may become a lot more interesting.

You can track the Cassini/Solstice mission tomorrow here:
http://saturn.jpl.nasa.gov/mission/flybys/enceladus20111001/

Rocks and Buggys

The best direct evidence we have to date of extraterrestrial life is in the form of microscopic inclusions in a small number of carbonaceous meteorites, which have the appearance of being fossilized prokaryotes. By far the best known of these is ALH 84001, the martian meteorite found in Allan Hills Antarctica in 1984.

Earlier this year NASAjavascript:void(0)/Huntsville scientist Richard Hoover announced that a number of non-martian meteorites also contain possible fossil prokaryotes. Below is both his abstract and a link to the entire paper in Journal of Cosmology.

Okay. So, I happen to like JoC. It's one of the many links from this blog, and I really like their philosophy of ensuring that all of the papers they publish are available to anyone free of charge. Most similar outlets only publish the abstracts free of charge. So, good on them for this. And good on them for maintaining some semblance of a peer-review process.

The bad news with JoC is that they have a very openly anti-scientific agenda, which tends to lead to the occasional publication of some really, really shoddy research. Regarding Hoover's work, they state that "Hoover's paper is further evidence that life is pervasive in this galaxy and exists on astral bodies other than Earth. The alternative view is life exists only on Earth, and originated on Earth, as described in the Jewish and Christian Bible and which is the official position at NASA. We believe the choice is simple: Religion vs Science. The Journal of Cosmology is devoted to promoting science."

This philosophy steers many of the papers published in JoC. Up to and including denying the Big Bang, not on the basis of any solid evidence but rather on the basis that it looks a little bit like Genesis and that Georges Lemaître happened to be a Catholic priest. Really. Presumably gene theory is also not "science" as JoC imagines that, because Gregor Mendel was an Augustinian monk.

JoC is in no way unique in this. Capital "S" Science, like capital "A" Atheism, is simply another fundamentalist religion, with its own canon world-views and orthodoxies and hence necessary heresies. It has adopted the old fundamentalist Christian mantra of "don't open your mind, your brains might leak out"; I consider "Science" to be one of the greatest threats to rational critical thought, and legitimate science, in our culture today.

Just because the Bible says something doesn't mean that it's categorically true. Just because the Bible says something also doesn't mean that it's categorically untrue. It's just a freaking book.

I'm not sure why Richard Hoover, a respected NASA scientist, did not publish his research through NASA, and instead published through the Journal of Cosmology. It doesn't exactly help his credibility. For the record, I think he's mostly right, and that NASA would have published his work, so I can only assume that his decision not to was political rather than scientific.

In any event, here is his paper. The entire thing is linked at the bottom.

==========================================================

Fossils of Cyanobacteria in CI1 Carbonaceous Meteorites:
Implications to Life on Comets, Europa, and Enceladus

Richard B. Hoover,
Space Science Office, Mail Code 62, NASA/Marshall Space Flight Center, Huntsville, AL 35812
Abstract

Environmental (ESEM) and Field Emission Scanning Electron Microscopy (FESEM) investigations of the internal surfaces of the CI1 Carbonaceous Meteorites have yielded images of large complex filaments. The filaments have been observed to be embedded in freshly fractured internal surfaces of the stones. They exhibit features (e.g., the size and size ranges of the internal cells and their location and arrangement within sheaths) that are diagnostic of known genera and species of trichomic cyanobacteria and other trichomic prokaryotes such as the filamentous sulfur bacteria. ESEM and FESEM studies of living and fossil cyanobacteria show similar features in uniseriate and multiseriate, branched or unbranched, isodiametric or tapered, polarized or unpolarized filaments with trichomes encased within thin or thick external sheaths. Filaments found in the CI1 meteorites have also been detected that exhibit structures consistent with the specialized cells and structures used by cyanobacteria for reproduction (baeocytes, akinetes and hormogonia), nitrogen fixation (basal, intercalary or apical heterocysts) and attachment or motility (fimbriae). Energy dispersive X-ray Spectroscopy (EDS) studies indicate that the meteorite filaments are typically carbon rich sheaths infilled with magnesium sulfate and other minerals characteristic of the CI1 carbonaceous meteorites. The size, structure, detailed morphological characteristics and chemical compositions of the meteorite filaments are not consistent with known species of minerals. The nitrogen content of the meteorite filaments are almost always below the detection limit of the EDS detector. EDS analysis of terrestrial minerals and biological materials (e.g., fibrous epsomite, filamentous cyanobacteria; mummy and mammoth hair/tissues, and fossils of cyanobacteria, trilobites, insects in amber) indicate that nitrogen remains detectable in biological materials for thousands of years but is undetectable in the ancient fossils. These studies have led to the conclusion that the filaments found in the CI1 carbonaceous meteorites are indigenous fossils rather than modern terrestrial biological contaminants that entered the meteorites after arrival on Earth. The δ13C and D/H content of amino acids and other organics found in these stones are shown to be consistent with the interpretation that comets represent the parent bodies of the CI1 carbonaceous meteorites. The implications of the detection of fossils of cyanobacteria in the CI1 meteorites to the possibility of life on comets, Europa and Enceladus are discussed. Keywords: Origins of life, CI1 meteorites, Orgueil, Alais Ivuna, microfossils, cyanobacteria, comets, Europa, Enceladus

http://journalofcosmology.com/Life100.html

Tiger, tiger, burning bright

Typically, in astronomy, "The Great Silence" refers to the (not actually surprising) lack of intelligent radio transmissions emanating from the nearby stars.

Today it apparently refers to the lack of intelligent or otherwise radio transmissions emanating from the commercial media regarding the NASA announcement of a high energy heat source on Saturn's moon Enceladus.

By "commercial media" I mean CNN, BBC, Fox and even Weekly World News. I gave up the search after WWN, although I was pleased to learn there that space aliens have been ditching the bodies of human abductees onto the surface of the moon, minus their bones. How DO they keep scooping larger news agencies like the BBC?

Anyway, none of the news outlets I checked had picked up the NASA story (the real one). Given the incredible opportunity this story presents for each of the media outlets to royally eff it up in their own special way, I was inclined to give NASA credit for cleverly hiding the story in plain sight and wording it so blandly that the media didn't notice it. But that would imply that the NASA press corp was "clever", and so far the available data does not fit that hypothesis very well.

My next hypothesis was that the news outlets did read the story and understand its implications, but were taking the responsible path of allowing the information to trickle into the public's consciousness in its own time. Then I remembered that I had included Fox News in my list.

The only conclusion I was left with was that the science editors of the various media really genuinely didn't understand the importance or the implications of the press release. So, allow me to break it down into itty bitty words for the journalists.

Saturn has a tiny moon called Enceladus. "Tiny" as in about 500 kilometers, or about 300 miles, in diameter. For comparison, if Enceladus happened to be sitting on Ellensburg WA, the sphere of the moon would reach to Aberdeen WA to the west, Pullman WA to the east, Warm Springs OR to the south and nearly to Chilliwack BC to the north. So, "tiny" as far as moons go, but you wouldn't want to have to store it in your basement.

Enceladus has an ice mantle which is about 5km thick, which is much thinner than the ice mantles of the Jovian moons. Beneath that is a salt water ocean, which happens to be rich in simple organic chemicals.

Now, here's the rub. Enceladus should be frozen solid. There really isn't a logical reason why the interior of Enceladus is warm enough to melt the ice. There are two standard candidates for this, the first being tidal expansion and contraction from the gravitational relationship with Saturn and Dione (another of Saturn's moons), and the second being radioactive decay of superheavy metals within the rocky interior of Enceladus. Neither of these explanations hold much water.

Mimas, yet another of Saturn's moons, is closer still to Saturn but frozen stone cold solid. And you wouldn't really expect a world with a gravity 0.01 times that of earth to have made very much uranium.

Furthermore, Enceladus' heat does not seem to be evenly distributed around the globe, but concentrated in one single very small area. A tidally induced underwater volcano might account for this, but we would expect that to be situated near the equator, either facing or opposing Saturn (like our own moon, Enceladus is tidally locked with Saturn, with the same side always facing the planet). However, it turns out that our lone hot-spot is precisely at the south pole.

Still, knowing that there was in fact a hot-spot, scientists computed the absolute maximum heat output which could be generated by a combination of tidal dynamics and radioactive decay. The very generous number they arrived at was 1.4 gigawatts.

The hot-spot is called the "tiger stripes", because it is a region of four nearly parallel and evenly spaced trenches, each about 80 miles long by 1 mile wide. Cassini recently measured the heat from the tiger stripes as 15.8 gigawatts. More than ten times the maximum which could be generated by any known natural phenomenon.

So, what are we looking at here?

The official SWAG (stupid wild-assed guess) from NASA and JPL is that it is a somehow anomalous flareup that Cassini just happened to capture. The problem with this is that the original 1.4 gigawatt number was the anomalous flareup. So we can probably throw that one out. That leaves us with two possibilities. Either we're seeing a previously unknown natural phenomenon, or we're seeing a previously unknown artificial phenomenon. Either way we're going to need a lot more data and a lot more research. And suddenly Saturn's moon system looks a lot more interesting.

Cassini finds 15.8 gigawatt energy source on Enceladus

Here is the link from the NASA story. Will post much more later, class starting in a couple of minutes.

The commercial media doesn't seem to have picked this up yet. When they do, they will make a mess out of it. Here's the full NASA press release, minus graphics:

================================================================

Cassini Finds Enceladus is a Powerhouse
03.07.11

PASADENA, Calif. – Heat output from the south polar region of Saturn's moon Enceladus is much greater than was previously thought possible, according to a new analysis of data collected by NASA's Cassini spacecraft. The study was published in the Journal of Geophysical Research on March 4.

Data from Cassini's composite infrared spectrometer of Enceladus' south polar terrain, which is marked by linear fissures, indicate that the internal heat-generated power is about 15.8 gigawatts, approximately 2.6 times the power output of all the hot springs in the Yellowstone region, or comparable to 20 coal-fueled power stations. This is more than an order of magnitude higher than scientists had predicted, according to Carly Howett, the lead author of study, who is a postdoctoral researcher at Southwest Research Institute in Boulder, Colo., and a composite infrared spectrometer science team member.

"The mechanism capable of producing the much higher observed internal power remains a mystery and challenges the currently proposed models of long-term heat production," said Howett.

It has been known since 2005 that Enceladus' south polar terrain is geologically active and the activity is centered on four roughly parallel linear trenches, 130 kilometers (80 miles) long and about 2 kilometers (1 mile) wide, informally known as the "tiger stripes." Cassini also found that these fissures eject great plumes of ice particles and water vapor continually into space. These trenches have elevated temperatures due to heat leaking out of Enceladus' interior.

A 2007 study predicted the internal heat of Enceladus, if principally generated by tidal forces arising from the orbital resonance between Enceladus and another moon, Dione, could be no greater than 1.1 gigawatts averaged over the long term. Heating from natural radioactivity inside Enceladus would add another 0.3 gigawatts.

The latest analysis, which also involved the composite infrared spectrometer team members John Spencer at Southwest Research Institute, and John Pearl and Marcia Segura at NASA's Goddard Space Flight Center in Greenbelt, Md., uses observations taken in 2008, which cover the entire south polar terrain. They constrained Enceladus' surface temperatures to determine the region's surprisingly high output.

A possible explanation of the high heat flow observed is that Enceladus' orbital relationship to Saturn and Dione changes with time, allowing periods of more intensive tidal heating, separated by more quiescent periods. This means Cassini might be lucky enough to be seeing Enceladus when it's unusually active.

The new, higher heat flow determination makes it even more likely that liquid water exists below Enceladus' surface, Howett noted.

Recently, scientists studying ice particles ejected from the plumes discovered that some of the particles are salt-rich, and are probably frozen droplets from a saltwater ocean in contact with Enceladus' mineral-rich rocky core. The presence of a subsurface ocean, or perhaps a south polar sea between the moon's outer ice shell and its rocky interior would increase the efficiency of the tidal heating by allowing greater tidal distortions of the ice shell.

"The possibility of liquid water, a tidal energy source and the observation of organic (carbon-rich) chemicals in the plume of Enceladus make the satellite a site of strong astrobiological interest," Howett said.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory, Pasadena, Calif., a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The CIRS team is based at NASA's Goddard Space Flight Center in Greenbelt, Md., where the instrument was built.

Drill Close to Reaching 14-Million-Year-Old Antarctic Lake

There are some significant differences between Lake Vostok and Europa; for example, we have no evidence of hydrothermal vents at the bottom of Vostok. That said, whatever is found at the bottom of the Vostok ice glacier will have very interesting implications for the search for life on Europa and Enceladus.

WIRED UK-- Lake Vostok, which has been sealed off from the world for 14 million years, is about to be penetrated by a Russian drill bit.
The lake, which lies 2.5 miles below the icy surface of Antarctica, is unique in that it’s been completely isolated from the other 150 subglacial lakes on the continent for such a long time. It’s also oligotropic, meaning that it’s supersaturated with oxygen: Levels of the element are 50 times higher than those found in most typical freshwater lakes.
Since 1990, the Arctic and Antarctic Research Institute in St. Petersburg in Russia has been drilling through the ice to reach the lake, but fears of contamination of the ecosystem in the lake have stopped the process multiple times, most notably in 1998 when the drills were turned off for almost eight years.

Now, the team has satisfied the Antarctic Treaty Secretariat, which safeguards the continent’s environment, that it’s come up with a technique to sample the lake without contaminating it. Valery Lukin told New Scientist: “Once the lake is reached, the water pressure will push the working body and the drilling fluid upwards in the borehole, and then freeze again.” The next season, the team will bore into that frozen water to recover a sample whose contents can then be analysed.
The drill bit currently sits less than 328 feet above the lake. Once it reaches 65 to 98 feet, the mechanical drill bit will be replaced with a thermal lance that’s equipped with a camera.
Time is short, however. It’s possible that the drillers won’t be able to reach the water before the end of the current Antarctic summer , and they’ll need to wait another year before the process can continue.
When the sample can be recovered, however, it’s hoped that it’ll shed light on extremophiles — lifeforms that survive in extreme environments. Life in Lake Vostok would need adaptions to the oxygen-rich environment, which could include high concentrations of protective enzymes. The conditions in Lake Vostok are very similar to the conditions on Jupiter’s moon Europa and Saturn’s moon Enceladus, so the new data could also strengthen the case for extraterrestrial life.
Finally, anything living in the lake will have evolved in relative isolation for about 14 million years, so it could offer a snapshot of conditions on earth long before humans evolved.
Full Story

Ice Volcanoes on Titan

Not quite as cool as the beer volcanoes in the Pastafarian version of heaven, but still pretty cool.

NASA's Cassini spacecraft has found possible ice volcanoes on Saturn's moon Titan that are similar in shape to those on Earth that spew molten rock.

Topography and surface composition data have enabled scientists to make the best case yet in the outer solar system for an Earth-like volcano landform that erupts in ice. The results were presented at the American Geophysical Union meeting in San Francisco.

"When we look at our new 3-D map of Sotra Facula on Titan, we are struck by its resemblance to volcanoes like Mt. Etna in Italy, Laki in Iceland and even some small volcanic cones and flows near my hometown of Flagstaff," said Randolph Kirk, who led the 3-D mapping work, and is a Cassini radar team member and geophysicist at the U.S. Geological Survey (USGS) Astrogeology Science Center in Flagstaff, Ariz.

Scientists have been debating for years whether ice volcanoes, also called cryovolcanoes, exist on ice-rich moons, and if they do, what their characteristics are. The working definition assumes some kind of subterranean geological activity warms the cold environment enough to melt part of the satellite’s interior and sends slushy ice or other materials through an opening in the surface. Volcanoes on Jupiter’s moon Io and Earth spew silicate lava.

Some cryovolcanoes bear little resemblance to terrestrial volcanoes, such as the tiger stripes at Saturn’s moon Enceladus, where long fissures spray jets of water and icy particles that leave little trace on the surface. At other sites, eruption of denser materials might build up volcanic peaks or finger-like flows. But when such flows were spotted on Titan in the past, theories explained them as non-volcanic processes, such as rivers depositing sediment. At Sotra, however, cryovolcanism is the best explanation for two peaks more than 3,000 feet high with deep volcanic craters and finger-like flows.

Full Story

Never tell me the odds.

In our discussion of possible new locations for human habitation in the solar system, I neglected one candidate which bears consideration. Especially given the fact that Saturn's tiny moon Enceladus "made the cut", the dwarf planet Ceres should at least be considered.

We don't know a great deal about Ceres, yet. We will know a great deal more in February of 2015 when the Dawn spacecraft arrives there, after its flyby of Vesta. Here's what we do know, compared to Enceladus:

                                      Ceres                                          Enceladus          

Size (Diameter)              943 km                                         504 km
Gravity                           0.03g                                            0.01g
Distance from Earth       250,000,000 km                            1,500,000,000 km

So, Ceres is about twice the diameter of Enceladus, with three times the gravity (although it is still minute: a 200 lb person on Ceres would weigh 6 lbs on Ceres as opposed to 2 lbs on Enceladus), and Ceres is about five and a half times closer than Enceladus. Like Enceladus and Callisto, Ceres has water ice on her surface and likely liquid water below this. Unlike Enceladus, Ceres also has substantial amounts of carbonaceous rock on its surface, which could potentially be utilized as building materials. 

Star Wars fans may balk at the idea of establishing a colony or outpost in the middle of an asteroid field, but the asteroid population of the Main Belt is actually quite sparse, and the asteroids are all orbiting the sun in similar ways so that the relative motion of any two adjacent Main Belt asteroids is very small. The greater risk is from solar radiation, which Ceres, unlike the surfaces of Enceladus or Callisto, is completely unprotected from by Saturn's or Jupiter's magnetospheres.

So, for all intents and purposes, Ceres completes the list of likely candidates for human settlement in the solar system in the near future.

For the record, See Threepio was a pessimist. The actual odds of a spaceship accidentally colliding with an asteroid in the Main Belt are less than one in one billion.

40 Acres and a Vacuum-Packed Mule

When thinking about colonization of other worlds and places within our solar system, I am reminded of how very unhappy many earthbound colonists have been with their new homes. When the Denny Party landed on Alki Beach in what was to become Seattle, the women and children wept at the realization that they had left civilization to be stranded upon some of the most temperate and arable land on the planet. They wept because they were far away from home, and because it was raining. Seattle rain. Not deluge, just steady drizzle. Plenty of water, plenty of food, November temperatures in the mid 50s, and the natives were friendly and helpful. But the settlers were heartbroken because it wasn't New York City, yet.

A closer (albeit fictional) analog to our potential planetary expats are the intrepid penguins from the movie Madagascar, who, having commandeered a merchant ship to Antarctica, set foot on the Antarctic ice and solemnly pronounce, "well, this sucks". 

Seattle, on the worst of days, is a hell of a lot more clement than Mars. Antarctica, on the worst of days, is a hell of a lot more clement than Mars.

So what would motivate thousands of people to relocate off-world to a place less hospitable than the least hospitable places on earth? To create, not just a scientific outpost like McMurdo Station in Antarctica, or a mining facility like Prudhoe Bay, but an actual frontier settlement?

What has caused people to create such colonies in the past? Here are a few possibilities.

Mineral or other wealth has always been a strong motivator, but there's no reason to imagine that we'll experience a Lunar or Martian Gold-Rush anytime soon. Mars has plenty of iron, but so does earth, and earth's iron deposits are a lot closer.

What Mars does have, however, is an awful lot of cheap real estate. Assuming that the cost of transporting a large number of families could be kept low per family, some people would likely be enticed by the possibility of owning a plot of land the size of, say, Japan. The land isn't arable, so they would be under no obligation to cultivate it. First generation homesteaders could congregate in a central community on Mars, and "tend" their lands from a distance. Once the central community was well-established, some settlers might well chose to actually homestead on their property. The central "city" would continue to grow, and smaller communities would crystallize around the outlying homesteads. In this way, large expanses of Mars could be colonized quickly, albeit sparsely.

One of the easiest ways to relocate large numbers of people from more desirable land to less desirable land is, um, against their will. Penal colonies, for example, have a long history of thriving in the most adverse conditions, and emerging within a few generations as a stable society. I'm actually a fan of penal colonies. But my ancestors were among the first European colonists of Australia, so I'm a direct result of one. The Botany Bay and Port Moresby colonies were unequivocally successful. A large penal colony on Mars or Callisto might, another century hence, be a sprawling metropolis like Sydney or Brisbane.

A slightly more benign corollary to the penal colony is the refugee camp. A population dislocated from their homeland by famine, war or persecution might well find impetus to settle on an alien world. It is not difficult to imagine a latter day Plymouth, or Salt Lake City, or Tel Aviv rising from the deserts of Mare Frigoris. 

It is also possible that utopianists would build a sanctuary from worldly ills on another world. Robert Heinlein envisioned a lunar libertarian utopia in The Moon is a Harsh Mistress, but I am inclined to imagine that it would be utopianists, if anyone, who would first settle Enceladus. Nestled within Saturn's rings, spinning like a top delicately perched on the ice, a rotating colony on the surface of Enceladus would be far removed from terrestrial worries and law enforcement, but habitable and comfortable for those willing to leave earth behind forever. And the views would be unequalled in the solar system.

These are a small number of possibilities, there are thousands more.

Whether I have created here a reasonable template for future out-migration, or simply the backdrop for a science fiction novel, only time will tell. But it has been an interesting thought-experiment.

Outmigration: Candidate Lineup

Assuming a minimum of 1 acre per person (including arable land) total space required for any of our colonies, and assuming an initial colony of 1000 individuals capable of expanding to 10,000 individuals, in each case we need 4 square km of habitable space initially which can be expanded to 40 square km of living space eventually. Each of these candidates have the potential to accomplish this.

Low Orbtal Toroidal Station

Distance ~ 1000 km from surface (ISS is 500 km)
Gravity: 1.0G, or whatever is desired
Escape Velocity ANY
Braking: Thrust only
Existing life potential: none
Resources: None
Radiation: Low
Asteroid vulnerability: low to moderate

Advantage: Easiest access of any candidate, full gravity
Disadvantage: All materials to build must come from earth.

L4 or L5 Langrangian Orbit Toroidal Station

Distance 400,000 km
Gravity: 1.0G, or whatever is desired
Escape Velocity ANY
Braking: Thrust only
Existing life potential: none
Resources: None
Radiation: High
Asteroid vulnerability: moderate to high

Advantage: Stable orbit, could build very large without need for propulsion, full gravity
Disadvantage: All materials to build must come from earth or moon.

Peary Crater (Moon)

Distance 400,000 km
Gravity: 0.2G
Crater Diameter 73 km
Escape Velocity 2.38 km/sec
Braking: Thrust only
Existing life potential: none
Resources: Rock, iron, limited water
Radiation: Low
Asteroid vulnerability: Low

Advantage: Close, ample resources for small colony
Disadvantage: Size of colony self-limiting, few similarly ideal locations on moon

Mars

Distance Variable, ~100,000,000km
Gravity 0.4G
Escape Velocity 5.03 km/sec
Weak atmospheric braking, high winds
Existing life potential: very low
Resources: Rock, iron, water
Radiation: Low
Asteroid vulnerability: Low

Advantage: Very large settlements possible, most "earth-like" of candidates
Disadvantage: Unless we find substantial fossil deposits, not much incentive to stay on Mars

Callisto

Distance ~800,000,000km
Gravity 0.1G
Escape Velocity 2.44 km/sec
Braking: Thrust only
Existing life potential: very low
Resources: Rock, iron, water
Radiation: Low
Asteroid vulnerability: Moderately High

Advantages: Good outpost for study of rest of Jupiter system
Disadvantages: Other than research, not much incentive to colonize

Enceladus

Distance 1,300,000,000km
Gravity 0.01G
Escape Velocity 0.24 km/sec
Braking: Thrust only
Existing life potential: moderate to high
Resources: Water
Radiation: Low
Asteroid vulnerability: High

Advantages: Gravity light enough that a rotating toroid built (or landed) on Enceladus could provide full gravity for inhabitants, while surface gravity sufficiently low for many low-G applications. LOTS of water ice. Great view. Good outpost for research of Titan.

Disadvantages: Very far away.


Tomorrow we'll look at some of the potential motivations to colonize, and from this make a best guess of which candidate would best serve each motive.

Enceladus, reconsidered

Early in this series on planetary outmigration I wrote off Saturn's moon Enceladus as being both too small and too distant. However, one aspect that I had not given serious thought to is the relative thinness of the surface ice, compared to the moons of Jupiter. Where Europa's ice is some 100km thick above her salty oceans and Ganymede's is close to 200km, the ice mantle on Enceladus is somewhere between 5km and 30km, with most estimates leaning toward the lower end of that spectrum. Now, compared to an average Arctic ice cap on earth of 3 to 4 meters, this is still an awful lot of ice. But when considering the time spent in transit from earth added to the time spent boring down to liquid water, Enceladus starts to compare pretty favorably to Jupiter's icy moons. But Enceladus is still tiny, which means her gravity is very weak (0.0113 earth gravities), which means that a 200 lb person would weigh a little more than 2 lbs. However, the surface radiation on Enceladus is quite low, and it is not entirely impossible that her very low gravity could be turned to an advantage.

Regardless of the difficulty in colonizing Enceladus, one thing is for certain. Any colony on the surface of Enceladus is going to have one hell of a view of Saturn, albeit edge-on through the rings.

Here are two composite photos which give a pretty good visual of the relative size of Enceladus:

Outward ho!

The previous post discussed one method of sending a crewed mission to Mars: one-way, all expenses paid.

What was not discussed, and needs to be, is whether or not NASA should be spending any of its precious and limited resources on crewed space exploration at all.

With the Space Shuttle missions nearing their end, NASA is (wisely) turning the business of low-orbital cargo and personnel runs over to the private sector. Spaceport America is nearly complete and should be fully operational by the middle of next year, with commercial flights to low orbit and commercial space stations finally becoming a reality.

This leaves two somewhat conflicting futures for NASA. The first, which seems to be getting the most funding from this current administration (which was decidedly not the case with the previous administration) is for unmanned deep space exploration, both in terms of next-generation replacements for Hubble such as the  James Webb Space Telescope, and also robot probes to the outer planets and their moons, and eventually to the nearest stars. The second is manned missions to the moon, Mars and beyond, with the ultimate goal of colonizing other worlds.

From the standpoint of pure research, this is a no-brainer. We do not need to send humans further into space than low earth orbit, and that only for routine maintenance of satellite telescopes. While it is true that a human is better equipped to respond to and analyze an alien environment than a robot is, it is still more cost effective (and much safer) to design and build better robots than it is to design missions around human life-support. 

So, what is the value in creating manned missions to the moon, Mars and beyond?

Certainly there is something of a Mount Everest factor; humans are exploratory by nature, we want to go simply because we can. This stands alone without further comment; we want to go to Mars because, dammit, we want to go to Mars.

Some have suggested exploiting the planets and their moons for natural resources, but this is not going to be in any way cost-effective within this century, and it may never be. Titan holds interesting promise as a source of hydrocarbons, but by the time we would be able to extract and transport them to earth we will have hopefully ended our dependence on hydrocarbons for fuel and plastics.

The last (and probably best) reason to colonize some territory beyond earth's atmosphere is that right now all of the human population's eggs are in one basket, and we're just barely wise enough to realize that if we want to survive as a species, this is a really bad idea. If humans remain exclusively on earth's surface, we will eventually become extinct. It really doesn't matter so much whether the immediate cause of that extinction is an asteroid strike such as what led to the extinction of the dinosaurs, a near-by gamma ray burster, a super-volcano, war, plague, famine or global warming. Any of these have the potential to eradicate all human life on earth, and any of these have the potential to happen within the next ten thousand years, or the next ten thousand minutes. And each of these allow some possibility of the human species surviving if we happen to have already colonized off-world if and when they occur. It seems that NASA and DARPA are both looking at this possibility in regard to serious proposals for outmigration.

First off, let me state that the fact that NASA and DARPA together have been allocated about $1,000,000 to study the possible means of outmigration means that the US government is not altogether paranoid about an asteroid hitting the earth this fiscal year. Of all of the possible means of human extinction, the one which is by far the most likely to actually cause that within the next century is global climate change, and we would be far better served spending our money eliminating our greenhouse gas emissions than building lifeboats to a planet which doesn't, as far as we know, support any life at all. But it is still reasonable to be preparing to get some of our eggs into a different basket, as a contingency for any of the myriad possible extinction-level events which could befall our world.

So, given our current technology, what are our best candidates in our solar system for a second home for our species?

I've given this a bit of consideration, and I'm going to name four candidates (which are not mutually exclusive of each other, it may well be that five baskets are better than two) for relatively easy colonization. Over the next few days I will talk about each candidate in more depth, and also discuss why I relegated a few candidates to the "B list" which others might not have. 

So, my four candidates for potential colonization within this century are, in order of proximity to earth:

1) A large earth-orbiting artificial space station

2) The moon

3) Mars

4) One (or all) of the three outer Galilean moons of Jupiter, probably either Europa or Ganymede but Callisto has some marks in its favor as well. We'll discuss the possible merits of each of these.

Why not Enceladus or Titan? Both are excellent candidates for finding extraterrestrial life, but neither would be especially hospitable to humans, even as such things go. Enceladus is really small, and Titan is toxic. Neither of these problems are insurmountable, but the other candidates pose fewer challenges.

More to come.