Interstellar Probe: The 1 KG Mission

Reading Charles Adler's Wizards, Aliens and Starships over the weekend, I've been thinking about starflight and cost. Subtitled 'Physics and Math in Fantasy and Science Fiction,' Adler's book uses the genres as a way into sound science, and his chapters contain numerous references to writers like Poul Anderson, Larry Niven and Robert Heinlein. On the matter of speculative propulsion systems, he lingers over fusion and describes the work of Project Daedalus back in the 1970s, when an ad hoc team of volunteer scientists and engineers put together a serious starship study. Like the vessels written about in the science fiction of that era and before, Daedalus was simply a mammoth craft -- 53 million kilograms! -- but that corresponded with what SF had been telling us all along. We would travel to the stars aboard vessels not so different from ocean liners, perhaps big enough to be livable on a daily basis, or at least big enough to pack thousands of humans into cryogenic containers for a...

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Rosetta: Target in Sight

The European Space Agency's Rosetta spacecraft, having traveled for ten years, is on track for its close-up investigation of comet 67P/Churyumov-Gerasimenko to begin later this year. Three years ago we had the first actual image of the comet, a 13-hour exposure taken shortly before the craft entered a lengthy period of hibernation. On the 20th of January, Rosetta was 'awakened' and controllers are in the process of commissioning its onboard instruments. As part of the process, we have two 'first-light' images taken on March 20 and 21. Image: Comet 67P/Churymov-Gerasimenko in the constellation Ophiuchus. This image was taken on 21 March by the OSIRIS Narrow Angle Camera. The comet is indicated by the small circle next to the bright globular star cluster M107. The image was taken from a distance of about 5 million kilometres to the comet. A wide-angle image was taken on 20 March. Credit & copyright: ESA © 2014 MPS for OSIRIS-Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA. We're seeing...

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Habitability: The Case for F-Class Stars

When it comes to habitable planets, we focus naturally enough on stars like our own. But increasing attention has been paid to stars smaller and cooler than the Sun. M-class dwarfs have small but interesting habitable zones of their own and certain advantages when it comes to detecting terrestrial planets. K-class stars are also interesting, with a prominent candidate, Alpha Centauri B, existing in our stellar back yard. What we haven't examined with the same intensity, though, are stars a bit more massive and hotter than the Sun, and new work suggests that this is a mistake. Manfred Cuntz (University of Texas at Arlington), working with grad student Satoko Sato, has been leading work on F-class stars of the kind normally thought problematic for life because of their high levels of ultraviolet radiation. Along with researchers from the University of Guanajuato (Mexico), Cuntz and Sato suggest that we take a closer look at F stars, particularly considering that they offer a wider...

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A Dwarf Planet Beyond Sedna (and Its Implications)

Most Centauri Dreams readers are hardly going to be surprised by the idea that a large number of objects exist well outside the orbit of Pluto and, indeed, outside the Kuiper Belt itself. The search for unknown planets or even a brown dwarf that might perturb cometary orbits in the Oort Cloud has occupied us for some time, with the latest analysis of WISE findings showing that nothing larger than Jupiter exists out to a distance of 26,000 AU. Objects of Saturn size or larger are ruled out within 10,000 AU, according to the work of Kevin Luhman (Penn State) and team, whose study probed deeply into the Wide-field Infrared Survey Explorer's results. For more on all this, see WISE: New Stars and Brown Dwarfs. But the evidence for objects big enough to perturb the local neighborhood does persist, even if we have to scale down our expectations as to its size. A new paper in Nature reports the discovery of 2012 VP113, a dwarf planet that joins Sedna in orbiting entirely beyond the Kuiper...

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Imaging Beta Pictoris b

This morning I want to circle around to a story I had planned to write about a couple of weeks ago. One thing writing Centauri Dreams has taught me is that there is never a shortage of material, and I occasionally find myself trying to catch up with stories long planned. In this case, the imaging of an exoplanet around the star Beta Pictoris demands our attention because of the methods used, which involve charge-coupled devices and wavelengths close to visible light. The detection marks real progress in visible light imaging of exoplanets. The work, which is slated to appear in The Astrophysical Journal, was conducted by researchers from the University of Arizona led by Laird Close. Charge-coupled devices (CCD) are the same kind of technology we find in digital camera imaging sensors, used here in a setting where we’d normally expect an infrared detector. But using infrared means viewing massive young planets hot enough to put out considerable heat. As the exoplanet hunt develops and...

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A Glassy Sea on Titan

The second largest sea on Titan is Ligeia Mare, made up of methane and ethane in a body of liquid that is larger than Lake Superior. Now we have word that the surface of Ligeia Mare is so utterly still that it would appear like glass. The news comes from Stanford University, where geophysicist Howard Zebker had led a new study based on Cassini measurements made in 2013. "If you could look out on this sea," said Zebker, "it would be really still. It would just be a totally glassy surface." Titan seizes the imagination not only because it is planet-like, with seas and a thick atmosphere, but because we know of no other body in the Solar System besides Earth that has a complex cycle involving solid, liquid and gas. Because the thickness of Titan's atmosphere compromises optical observations, Cassini bounced radio waves off the surface and analyzed the resulting echo. Wave action could be measured by the strength of the returning echo. Zebker explains in this Stanford news release that...

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What Kardashev Really Said

Whenever we're audacious enough to categorize far future civilizations, we turn to the work of Nikolai Kardashev. Nick Nielsen today looks at the well known Kardashev scale in the light of a curious fact: While many use Kardashev's rankings in their own speculations, few have gone back and dug into his original paper. In Kardashev's terms, our planet is close to attaining Type I status, which would surprise many commentators. And doesn't the ambiguity over what constitutes the energy of a star -- red dwarf? red giant? -- play havoc with cut and dried 'type' definitions? How subsequent writers have adapted and modified the Kardashev scale makes for a cautionary tale about mastering our sources before using them for further extrapolation. For that matter, are there better gauges of a civilization than its use of particular energy resources? Answering the question deepens the debate that Kardashev so fruitfully began. by J. N. Nielsen The name of Nikolai S. Kardashev is synonymous with...

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Solar Probe Plus: Prelude to ‘Sundiver’?

'Sundiver' maneuvers are surely the most extreme events to which we could subject a solar sail. To my knowledge, it was Gregory Benford who first came up with the term -- he mentions in Fantasy & Science Fiction that he passed the coinage on to David Brin when Brin was working on the book that would bear its name (Sundiver, published in 1985, would be the first volume in Brin's Uplift Saga). But Benford credits Brin with the actual concept, which he needed to make his plot work, so it seems best to give credit to both writers for an idea both went on to explore, Benford not only in fiction but in scientific papers as well. The maneuver is straightforward if breathtaking. Benford explains it in terms of a carbon sail being deployed in low Earth orbit and then launched into deep space by microwave beam: Consider the sundiving sail. Approaching the Sun turned edge-on (to prevent the increasing flux of sunlight from pushing against its fall), the carbon sail heats up. At closest...

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From Cosmism to the Znamya Experiments

What got me thinking about French influences on early solar sail work in Russia yesterday was the realization that science fiction was much stronger in Europe, and particularly France, in the latter part of the 19th Century than we Americans might realize. Hugo Gernsback to the contrary, the genre did not emerge in 1926 with the appearance of Amazing Stories, nor did key early texts like Mary Shelley's Frankenstein launch the genre in England. Brian Aldiss would probably argue with this (see his Trillion Year Spree, 1973), but I agree with Brian Stableford in seeing a true genre emerging first on French soil. Whether you agree or not, have a look at Stableford's essay The French Origin of the Science Fiction Genre, where I find this in reference not only to Verne but writers like George Sand (Laura: voyages et impressions, 1865) and Camille Flammarion (Récits de l'infini, 1872): These works were sometimes referred to by contemporary commentators as examples of roman...

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SF Influences: A Solar Sail Theory

Last week I looked at three figures who put solar sails on the map in the 1950s -- Carl Wiley, who wrote the concept up in Astounding, Ted Cotter, who analyzed it for colleagues at Los Alamos, and Richard Garwin, who brought solar sailing into the academic journals. It was not long after Garwin's work that science fiction pounced on solar sails through a cluster of memorable stories beginning with Cordwainer Smith (Paul Linebarger) and "The Lady Who Sailed the Soul." More about that story and its era soon, including work by Poul Anderson, Jack Vance, and perhaps the best known of all from that era, Arthur C. Clarke's "Sunjammer." But today let's go way back to what is I think the first story that ever dealt with raw light as a propulsive mechanism. Georges Le Faure and Henri de Graffigny published Aventures extraordinaires d'un savant russe (The Extraordinary Adventures of a Russian Scientist) in three volumes beginning in 1889, with a fourth volume coming out under the promising...

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Creative Constraints and Starflight

I discovered Karl Schroeder's work when I was researching brown dwarfs some years ago. Who knew that somebody was writing novels about civilizations around these dim objects? Permanence (Tor, 2003) was a real eye-opener, as were the deep-space cultures it described. Schroeder hooked me again with his latest book -- he's dealing with a preoccupation of mine, a human presence in the deep space regions between ourselves and the nearest stars, where resources are abundant and dark worlds move far from any sun. How to maintain such a society and allow it to grow into something like an empire? Karl explains the mechanism below. Science fiction fans, of which there are many on Centauri Dreams, will know Karl as the author of many other novels, including Ventus (2000), Lady of Mazes (2005) and Sun of Suns (2006). by Karl Schroeder My newest science fiction novel, Lockstep, has just finished its serialization in Analog magazine, and Tor Books will have it on the bookshelves March 24....

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Solar Sailing Moves into the Journals

I'm just getting started with Chris Impey and Holly Henry's Dreams of Other Worlds (Princeton University Press, 2013), but glancing through it yesterday reminded me how long it has taken sail hardware to get into space. While Ted Cotter and Carl Wiley hoped for early experiments with sail ideas, we never got them until much later. Interesting mission concepts like JPL's 'gyro' sail to Halley's Comet did develop (although it never flew), and the Soviet Znamya deployments gave us some experience with thin membranes in space (I'll talk about those soon), but by and large we left interplanetary exploration for the rockets. The deep space probes and near-Earth observatories Impey and Henry cover -- Viking, Voyager, Stardust, Chandra, Hubble and their ilk -- gave us outstanding results but were not, until IKAROS, joined in space by alternative sail technologies. I'll review this book in some detail as soon as I finish it, but for today let's go back to the late 1950s, a time when Carl...

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A Sail Mission Emerges

Carl Wiley, the prescient engineer who offered an early description of solar sails in "Clipper Ships of Space" (Astounding Science Fiction (May, 1951), was not the first to look into sail propulsion, but he was one of the more visible. Konstantin Tsiolkovsky's thinking on the matter in the 1920s was not widely circulated, and it may be that John Desmond Bernal, a political activist and professor at Cambridge and, later, the University of London, was Wiley's primary forerunner as far as public awareness of sail ideas is concerned. In The World, the Flesh & the Devil (1929), Bernal looked at the propulsive possibilities in light: However it is effected, the first leaving of the earth will have provided its with the means of traveling through space with considerable acceleration and, therefore, the possibility of obtaining great velocities - even if the acceleration can only be maintained for a short time. If the problem of the utilization of solar energy has by that time been solved,...

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Solar Sails: Remembering Carl Wiley

If you're interested in solar sails and find yourself in California, a stop by UC Riverside's Tomás Rivera Library should be worth your time. There you will find the Carl A. Wiley collection on solar sails, containing books, manuscripts and various other materials related to sail technologies. Wiley was an aeronautical engineer who wrote the first detailed article on solar sails to reach a wide audience. Evidently concerned about the venue -- Wiley's article had been accepted by John Campbell's Astounding Science Fiction, which some of his colleagues might not have taken seriously -- he chose to write under the pseudonym 'Russell Saunders.' Finding Wiley's papers at Riverside is perhaps no surprise, given that this is the home of the Eaton Collection of Science Fiction & Fantasy, 'the largest publicly-accessible collection of science fiction, fantasy, horror and utopian literature in the world.' Pulp magazine enthusiasts like myself will note that the archive houses full runs of many...

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WISE: New Stars and Brown Dwarfs

Just how early we are in our thinking about traveling beyond the Solar System is revealed in a comment made by Ned Wright, principal investigator of the WISE mission. "We don't know our own sun's backyard as well as you might think," said Wright. And he goes on to say, "We think there are even more stars out there left to find with WISE." That's a wake-up call indeed given how much WISE has already told us, and what two new studies have brought to light. Davy Kirkpatrick (Caltech) led one of these, examining data from the Wide-field Infrared Survey Explorer mission that performed two full scans of the sky in 2010 and 2011, capturing images of almost three-quarters of a billion galaxies, stars and asteroids. Analyzing data using NASA's AllWISE program, which makes it possible to compare the datasets more effectively, Kirkpatrick's team found 3,525 new stars and brown dwarfs within 500 light years of the Sun. These objects, says Kirkpatrick, were totally overlooked before now. In any...

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Woven Light: Augmented Dreamstate

Heath Rezabek, an Austin, TX-based librarian, futurist and long-term thinker, continues the chronicle of his evolving work on the Vessel project and its ramifications. Developed as a strategy for preserving our cultural and biological heritage, Vessel is inevitably a way to re-examine ourselves in new and startling ways. Science fiction offers a supple way to visualize what generations in the near and far future may draw from such archives, leading perhaps to created intelligences that grow by sampling our imagery, our artifacts, our mythologies. In the passage that follows, we meet an SF writer named Thea Ramer, and learn more about Dr. Kaasura, whose early work with Vessel points to synthetic minds, re-woven patterns of quantum reality and the development of Saudade-class starships. But let Heath explain... by Heath Rezabek This is the third installment in a continuing series of speculative fiction here on Centauri Dreams. Feedback from prior installments helps shape the themes and...

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Measuring Atmospheric Pressure on Exoplanets

We haven't talked much in these pages about atmospheric pressure when it comes to characterizing exoplanets, but recent discussions of 'super-Earths' and thick, hydrogen/helium atmospheres have raised the issue. All but simultaneously came the news of a paper from Amit Misra (a University of Washington graduate student) and co-authors describing a new way of detecting atmospheric pressure on exoplanets. Misra's simulations of Earth's own atmospheric chemistry involved teasing out the signature of dimer molecules from light at various wavelengths. While a monomer is a molecule that may bind chemically to other molecules, a dimer is a chemical compound made up of two similar monomers bonded together. Misra's work is intriguing because the stability of water on a planet's surface depends not just on temperature but pressure -- the latter affects water's boiling point and sublimation. Estimating surface pressure thus becomes an indicator for potential habitability. The problem is that...

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Red Dwarfs: Planets in Abundance

Whether or not they’re suitable for life, habitable zone ‘super-Earths’ are seeing increased scrutiny around M-class dwarf stars because the mass ratio of planet to star makes detection easier than around more massive stars. We need radial velocity surveys to help us here because planets on orbits longer than 200-300 days will definitely be out of Kepler’s reach. Moreover, while Kepler targets many K, G and F-class stars, M-dwarfs aren’t bright enough to show up in large numbers in its field of view, making occurrence rates around such stars problematic. A 2013 paper by Courtney Dressing and David Charbonneau (Harvard-Smithsonian Center for Astrophysics) found that the Kepler sample contains 3897 stars with estimated effective temperatures below 4000K. Out of these, 64 are planet candidate host stars, with 95 candidate planets orbiting them. The researchers deduced from their analysis that about 15 percent of all red dwarfs have an Earth-sized planet in the habitable zone. Ravi...

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An Interstellar Mission Statement

Yesterday I wrote about what Michael Michaud calls 'the new cosmic humanism,' looking back at an essay the writer and diplomat wrote for Interdisciplinary Science Reviews in 1979. Intelligence, Michaud believes, creates the opportunity to reverse entropy at least on the local scale, and to impose choice on a universe whose purpose we do not otherwise understand. Continuing growth into space, expansion and discovery are the kind of long-term goals humans can share, highlighting the extension of knowledge and the rediversification of our species. What Michaud is talking about is nothing less than a mission statement for extraterrestrial man, one that trades off a key uncertainty: In the face of an indifferent universe, intelligence itself may prove to be an evolutionary quirk that is of little consequence. Whether or not this is the case could depend on the decisions and purposeful choices of intelligent beings, assuming they choose to expand into the cosmos. Let me quote Michaud on...

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Toward an Extraterrestrial Paradigm

Growing up in the Sputnik era, I followed the fortunes of space exploration with huge enthusiasm. In those days, the model was primarily planetary in nature, the progression from the Moon to the nearest planets and then beyond seemingly inevitable. At the same time, a second model was developing around the idea of space stations and self-contained worlds built by man, one that would reach high visibility in the works of Gerard O'Neill, but one that ultimately reached back as far as the 1920's (Oberth and Noordung) and further back to the science fiction of Jules Verne. In fact, E. E. Hale's "The Brick Moon" explored a space station as early as 1869. But even as our Mariners and Veneras explored other planets, an interstellar thread was also emerging. Robert Goddard wrote about interstellar journeys in 1918, science fiction was full of such travel as the field matured in the 1940s and '50s, and serious scientific study of interstellar flight became established by mid-century. Writing...

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Charter

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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