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Cryovolcanism on Charon?

by Paul Gilster | Jul 16, 2009 | Outer Solar System | 5 Comments

Gentry Lee (Jet Propulsion Laboratory) discusses the question of extraterrestrial life on a program called Are We Alone, which airs this evening on the Discovery Channel at 2100 EDT (0100 UTC on the 17th). Lee is chief engineer for the Solar System Exploration Directorate at the Jet Propulsion Laboratory, a veteran of Viking and Galileo, and a co-author of Arthur C. Clarke. He was also involved with Carl Sagan on COSMOS, so he knows something about video productions. Pushing Back Astrobiology As I've noted in the two previous posts, we're moving into an era of re-examination of the Solar System. It's one that leads inevitably to a new understanding of the concept of habitable zones, with life now being considered a possibility on places that were once thought off-limits. Europa is unusual enough, but the evidence for that ocean beneath the ice is persuasive. Can we extend the paradigm all the way out to the Kuiper Belt? If so, missions like the Haumea orbiter or probes to other...

Haumea: Technique and Rationale

by Paul Gilster | Jul 15, 2009 | Outer Solar System | 11 Comments

Yesterday's look at a fast orbiter mission to Haumea raises useful questions. The mission, developed conceptually by Thales Alenia Space and presented at Aosta by Joel Poncy, is particularly demanding because this outer system object has no atmosphere. You can make the case for a Neptune orbiter with associated study of Triton, as several readers have already done, but if you want to orbit Haumea, no aerobraking is possible to ease orbital insertion. The Haumea mission, in other words, deliberately pushes the state of the art in both propulsion and power generation. Poncy noted in his talk at the Hotel Europe that his team had adapted an in-house software model to optimize the propulsion possibilities. The team considered only electric or magneto-plasma technologies (for the latter, think VASIMR -- Variable Specific Impulse Magnetoplasma Rocket). They assume a direct trajectory to Haumea with arrival around 2035, when the object is at 49 AU, and they weigh the benefits of a gravity...

Fast Orbiter to Haumea

by Paul Gilster | Jul 14, 2009 | Outer Solar System | 16 Comments

One of the surprises of the Aosta conference was Joel Poncy's presentation on a fast orbiter mission to Haumea. Poncy (Thales Alenia Space, France) and colleagues have been developing ideas for the extraordinarily difficult challenge of not just sending a probe to the outer system, but slowing it down for orbital capture. It's one thing to do this, say, for Neptune, where a thick atmosphere can be used for aerobraking, but it's quite another to contemplate doing the same for an airless trans-Neptunian object (TNO) like Haumea. Nonetheless, there are solid reasons for thinking about such a mission. The first is purely scientific. As Poncy did, I'll use outer planet specialist Mike Brown's illustrations of what has happened to our Solar System in the last few decades. The first illustration shows the Solar System most of us grew up with, a system with nine planets that were more or less clearly defined, with what was assumed to be a certain amount of debris and cometary material...

Back from Italy, We Turn to Nanotech

by Paul Gilster | Jul 13, 2009 | Advanced Rocketry | 8 Comments

One of the things that makes travel both entertaining and exasperating is the assurance that the best laid plans will come up against events beyond your control. Thus I arrived at Milan's Malpensa airport in plenty of time for my Delta flight, only to be told that the flight had been canceled. But Delta moved quickly on setting me up with an Alitalia flight to New York that left only thirty minutes after the first had been scheduled to leave, and after two more connections (and a twenty-three hour day on the move) I arrived back home. The photo is a shot of the streets of Aosta one early morning, from a walk I took on the last day to remember it by. I returned with a satchel full of notes, the conference proceedings, numerous business cards and the world's worst back-ache, a consequence of trying to move too fast in crowded airports with laptop and luggage. While the latter heals, I've also decided not to try to move through the Aosta material in one go -- there's too much of it, and...

A Milanese Morning (with NEOs)

by Paul Gilster | Jul 10, 2009 | Asteroid and Comet Deflection | 4 Comments

The driver who took me from Aosta to Milan yesterday evening spoke no English, but he was an affable young man who had a love for fast cars. As we drove along a fine Alpine highway, a low red sports car moved fast us so quickly that I almost didn't see it. But suddenly the driver, who had said next to nothing thus far, erupted with "Italian car! Beautiful!" He stretched out the last word as if savoring the idea, then looked over at me making a thumbs up. Well, it was beautiful, and it was followed by two more similar cars making speeds I could only guess at. I wondered what it felt like to drive such a car, and how quickly it would get to Milan. One of the best things about wrapping up the Aosta conference, which we did with a farewell party yesterday afternoon, is that I head back to the States with a satchel full of papers. I've only been able to mention a few of them thus far, but next week I should have the chance to talk about them at more leisure. Here in Milan I have a few...

Aosta Update for Thursday

by Paul Gilster | Jul 9, 2009 | Culture and Society | 2 Comments

I'm just in from an early morning walk around the streets of Aosta, enjoying a brisk spring morning. The streets at this hour are largely empty and the Sun lights the nearby peaks. We have a heavy session of papers on this last day of the conference, and we had an even longer day yesterday, followed by my public lecture at the Aosta town hall last night. Following the talk, Giancarlo Genta, his lovely wife Franca, and Guido Cossard, the assessore of cultural affairs (who turns out to be an astronomy buff and something of an expert on archaeoastronomy), took me on a walk around town looking at medieval and Roman sites. We wound up having a late night beer and I didn't get in until 1:30. This is a travel day, as I change hotels in preparation for tomorrow's flight from Milan. So I'm going to hold any of the discussion about the papers yesterday, which were so rich that I'd prefer to get into them when I have more than a few minutes. In particular, the solar sail sessions opened my eyes...

Aosta Update for Wednesday

by Paul Gilster | Jul 8, 2009 | Culture and Society | 15 Comments

Today we get into the heart of this interstellar conference, with multiple sessions on propulsion via solar and electric sail, as well as looks at specific mission concepts and robotic applications in deep space. I spent a good part of our bus ride back from Bard castle yesterday talking to Pekka Janhunen, creator of the electric sail concept, about its possible interstellar applications. Pekka does not believe this system, based on electric tethers riding the solar wind, could muster the velocity to go interstellar, but he does see it as a viable candidate for braking into a destination system, and just as important, exploring it. I'm anxious to get the latest on his work and also to look at fusion alternatives, which Claudio Maccone will present now that we've learned that Claudio Bruno can't make it here. As I get ready for the day to start, I'll drop in here some notes from the first day. These are no more than a skeletal outline -- I'll use the conference proceedings when I get...

Busy Times in Northern Italy

by Paul Gilster | Jul 7, 2009 | Culture and Society | 4 Comments

I had intended to use today's post to talk about yesterday's sessions here in Aosta, but it's going on midnight here, and tomorrow will clearly not afford any opportunities to write. Tuesday turns out to be our sightseeing day. We leave the hotel at 9:00 and head for Verrès, where we visit the Mechatronics Laboratory of the Politecnico di Torino. Then we head up into the mountains, visiting the Bard fortress, with individual visits to the Museum of the Alps. After lunch at what is said to be an excellent restaurant called La Polveriera, we go to an exhibition called 'Verso l'alto, l'ascesa come esperienza del sacro' -- Towards the heights: The ascent as experience of the sacred. Then to dinner at the Hotel Notre Maison, where we are promised traditional Aosta Valley food. Image: The Aosta town hall, where our opening sessions were held. Later, we moved to the Hotel Europe. As for tomorrow, we don't get back to the hotel until midnight. No more today or I'll be late for the bus, but...

First Day in Aosta

by Paul Gilster | Jul 6, 2009 | Culture and Society | 2 Comments

What I'll surely remember the most about arriving in Italy is the sight of snow on the Alps as the plane descended out of a cloudy morning sky into Milan. But right after that comes the two hang gliders that soared past an alpine peak as the van that was taking me to Aosta moved north toward the town, the landscape becoming a series of valleys cutting through the steep clefts. The second of the two hang gliders looked for all the world as if it were going to land right on the highway, a daunting thought given how the traffic was moving, but as we rounded a turn I saw that it had caught an updraft and was angling out and away. What a view the pilot must have had. Image: The view from my room at the Hotel Europe in Aosta. It was hot and humid when I took this, but cooled off dramatically during the night. If the air conditioner worked, all would be perfect. Below is a photo from the street in front of the hotel. As you can tell, this is the place to be for a guy who loves mountains the...

Notes & Queries 7/3/09

by Paul Gilster | Jul 3, 2009 | Culture and Society | 38 Comments

Night Flight to Italy I'm off tomorrow night to Italy, specifically to the Sixth IAA Symposium on Realistic Near-Term Advanced Scientific Space Missions. I'll be delivering a talk at the conference and a public lecture in the town of Aosta and, assuming a robust Internet connection, I'll also be sending along news of the conference as it unfolds. I'm looking forward particularly to catching up with Giancarlo Genta, Greg Matloff and wife C Bangs, and Claudio Maccone, and it will be great to touch base again with Les Johnson, whom I haven't seen since we talked at Marshall Space Flight Center in 2003. Superluminal Radio Waves and their Uses An article in the Santa Fe New Mexican discusses the work of John Singleton, a physicist at Los Alamos National Laboratory, who has created a 'polarization synchrotron,' which according to the report pushes radio waves faster than the speed of light. In a paper on this work, Singleton explains that: ...though no superluminal source of...

Two Stars, Two Systems?

by Paul Gilster | Jul 2, 2009 | Exoplanetary Science | 11 Comments

Imagine what space exploration would look like if the Sun were a member of a binary system. Suppose we had another star a few hundred AU away, one that had built its own planetary system. The second star, a thousand times brighter than any other star in our night sky, would be an object of obvious interest, its planets visible to our astronomers and reachable targets for early space technology. The question of life on a planet in that star's habitable zone would be relatively easy to resolve, and the imperative to study that world first-hand would surely drive space science. Now we learn that a binary system some 1300 light years from Earth may be evolving in a similar direction. Located in the Orion Nebula, a region rich in star-birth, the stars are about a third the mass of the Sun, considerably cooler and redder in color. One is known to be an M2 dwarf, while the other's spectral type hasn't been precisely identified because of obscuration by the disk. The stars are 400 AU apart,...

Of Technological Lifetimes and Survival

by Paul Gilster | Jul 1, 2009 | Culture and Society | 33 Comments

Is the movement toward ever more sophisticated technology irreversible? If you've studied history, the answer is obviously no. Various speculations arise from this -- Carl Sagan once opined that without the intervening collapse known as the Dark Ages, we might have seen a Greek civilization exploring near-Earth space a thousand years ago. It's also likely that no law prevents another collapse into technological and scientific somnolence, perhaps sparked by war, or disease, or economic catastrophe. This is why I always hedge my bets when asked about timetables for space exploration. How long until we get humans to the outer system? How long until we launch a fast starship? Everyone is in a hurry, but so much depends on whether we keep growing our technology. Nanotechnology, for example, could change everything, but it's one thing to be using molecular assemblers by the end of the century, and quite another to see the fruition of this work stalled for a millennium by external events....

‘Blobs’ Flag Early Galaxy Formation

by Paul Gilster | Jun 30, 2009 | Deep Sky Astronomy & Telescopes | 2 Comments

Look back far enough in time (and hence far enough in distance) and you see things that don't correspond to nearby cosmic objects. The so-called 'Lyman-alpha blobs' that astronomers have found associated with young, distant galaxies are a case in point. Huge collections of hydrogen gas (some of them the largest single objects yet found in the universe), they're bright at optical wavelengths, raising the question of what powers the glow and how they factored into the galaxy formation process. New research may be offering an answer. The key is something called 'feedback,' a stage in galaxy formation that shows the interplay between galaxies and the intergalactic medium. Here, the cooling of gas within the dark matter halos enshrouding a young galaxy is countered by heating from active galactic nuclei (think supermassive black holes), which helps to enrich intergalactic space and also slow down star formation. Image: An artist's representation showing what one of the galaxies inside a...

Finding Life in the Ice

by Paul Gilster | Jun 29, 2009 | Astrobiology and SETI | 10 Comments

As we contemplate using long-range tools like spectroscopy to examine distant exoplanets for life, we're also developing the hands-on equipment we'll need for seeking it out in our own Solar System. Project SLIce (Signatures of Life in Ice) is a case in point, an attempt to study how organic material behaves in ice on other worlds by using Earth settings as an analogy. On that score, the archipelago of Svalbard has proven to be a helpful testbed. Located in the Arctic Ocean between Norway and the North Pole, Svalbard is icy and spectacular. The image below conjures up memories of a nautical journey I took around Iceland in the 1970s, with white-capped seas pushing up against snow-clad peaks. The SLIce team sees Svalbard as a laboratory for looking for extant or extinct life, and a place to develop the protocols for working with rovers in operating environments like Mars. Image: I love Iceland, but pushing as far north as Svalbard would really bring out the adventurer in me. Here we...

A Cometary Closeup for NExT

by Paul Gilster | Jun 26, 2009 | Asteroid and Comet Deflection | 3 Comments

By Larry Klaes Apropos of yesterday's story on the possible cometary origin of the Tunguska Event in 1908, Tau Zero journalist Larry Klaes looks at the NExT (New Exploration of Tempel) mission, which gives us a second crack at observing comet Tempel 1. Ancient artifacts of the early Solar System, comets can tell us much about its earliest days, but as Larry points out, getting data out of the Deep Impact mission proved to be unexpectedly complicated. NExT is a useful re-purposing of an earlier mission that may unlock further cometary secrets when it returns to Tempel 1 in 2011. If a comet did cause Tunguska, here's hoping such events continue to be rare, but in the meantime, garnering all the information we can about how comets are made is as important for planetary security as it is for the study of Solar System origins. An Impact to Remember Late on the Fourth of July in 2005, while fireworks brightened the sky across the United States, another group of American citizens were...

Comet Implicated in Tunguska Blast

by Paul Gilster | Jun 25, 2009 | Asteroid and Comet Deflection | 9 Comments

Back in my flying days, I found myself becoming absorbed with meteorology, enough to wind up teaching the subject in various flight school settings. I was no expert, but looking for clues on flying conditions in the next few hours by studying cloud formation and movement was fascinating. In all that time, the one cloud phenomenon I always wanted to see but never did was the noctilucent cloud, an unusual, lovely formation made up of ice particles that occurs at extremely high altitudes. 'Noctilucent' means 'night-shining,' and that's just what these clouds do when they're illuminated by sunlight from below the horizon. Space Shuttle launches have been found to generate them as the vehicle pumps about 300 metric tons of water vapor into the thermosphere, the layer of atmosphere beginning at about ninety kilometers above the surface, just above the mesosphere. Photographs of such clouds show a unique beauty, though it's one that might also seem eerie, at least in certain settings. For...

Enceladus: Riddle of the Plumes

by Paul Gilster | Jun 24, 2009 | Outer Solar System | 4 Comments

Is there really an underground ocean on Enceladus? The Cassini spacecraft's striking images have created a cottage industry in speculation, with spectacular glimpses of erupting plumes composed of ice and water vapor. This week, however, we get two contrasting views on what all this means. In one, a paper in Nature by a European team led by Frank Postberg (Universität Heidelberg), studies of sodium salts in dust ejected by the Enceladus plumes reveal telltale signs of a salty ocean deep below the surface. Postberg was working with data from the Cosmic Dust Analyzer (CDA) instrument aboard Cassini, and the results imply a level of sodium chloride that may be as high as that found in Earth's oceans. The data come from ice grains in Saturn's E-ring, which is thought to consist largely of material from Enceladus. Thus we seem to be gathering direct evidence for the presence of the hypothesized ocean, which should be salty from long contact with the rocky core. But not so fast. The same...

SETI: A Detectable Neutrino Signal?

by Paul Gilster | Jun 23, 2009 | Astrobiology and SETI | 24 Comments

Somehow I never thought of the IceCube neutrino telescope as a SETI instrument. Deployed in a series of 1,450 to 2,450 meters-deep holes in Antarctica and taking up over a cubic kilometer of ice, IceCube is fine-tuned to detect neutrinos. That makes it a useful tool for studying violent events like galactic collisions and the formation of quasars, providing insights into the early universe. But SETI? Perhaps, says Zurab Silagadze (Novosibirsk State University), who notes that most SETI work in the past has focused on centimeter wavelength electromagnetic signals. Says Silagadze: Here we question this old wisdom and argue that the muon collider, certainly in reach of modern day technology... provides a far more unique marker of civilizations like our own [type I in Kardashev's classification... Muon colliders are accompanied by a very intense and collimated high-energy neutrino beam which can be readily detected even at astronomical distances. Image: The IceCube array in the deep ice,...

TESS Mission Fails to Make the Cut

by Paul Gilster | Jun 22, 2009 | Missions | 13 Comments

NASA has made its choices, and TESS is not one of them. The Transiting Exoplanet Survey Satellite would have used six telescopes to observe the brightest stars in the sky, a remarkable 2.5 million of them, hoping to find more than 1,000 transiting planets ranging in size from Jupiter-mass down to rocky worlds like our own. An entrant in the agency's Small Explorer program, TESS could have accelerated the time-frame for discovering another habitable world, assuming all went well. Not that we don't have Kepler at work on 100,000 distant stars, looking for transits that can give us some solid statistical knowledge of how often terrestrial (and other) planets occur. And, of course, the CoRoT mission is actively in the hunt. But TESS would have complemented both, looking at a wide variety of stars, many of which would have been M-dwarfs. Not long ago I referred to a Greg Laughlin post that noted a 98 percent probability that TESS would locate a potentially habitable transiting planet...

Brute-Force Engineering and Climate

by Paul Gilster | Jun 19, 2009 | Culture and Society | 36 Comments

The eruption of Mt. Tambora in Indonesia in 1815 pumped so much sulfur dioxide into the stratosphere that New England farmers found their fields frosted over in July. Climate change, it seems, can be quick and overwhelming, at least on short scales. The eruption of the Mt. Pinatubo in the Philippines in 1991 cooled global temperatures for several years by about half a degree Celsius. Sulfur dioxide works. So how about this: We send a fleet of airships high into the stratosphere, attached to hoses on the ground that pump 10 kilos of sulfur dioxide every second. The airships then spew this mix into the upper atmosphere, a aerosolized pollutant that, turning the skies Blade Runner red, shields the planet from the Sun's heat. Call it geo-engineering, an extreme form of human climate manipulation that is the subject of a recent story in The Atlantic. Into the Anthropocene Writer Graeme Wood notes that our activities have been transforming the planet for centuries now, leading some to dub...

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In Centauri Dreams, Paul Gilster looks at peer-reviewed research on deep space exploration, with an eye toward interstellar possibilities. For many years this site coordinated its efforts with the Tau Zero Foundation. It now serves as an independent forum for deep space news and ideas. In the logo above, the leftmost star is Alpha Centauri, a triple system closer than any other star, and a primary target for early interstellar probes. To its right is Beta Centauri (not a part of the Alpha Centauri system), with Beta, Gamma, Delta and Epsilon Crucis, stars in the Southern Cross, visible at the far right (image courtesy of Marco Lorenzi).

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