by Paul Gilster | Dec 8, 2011 | Astrobiology and SETI |
Beamed propulsion continues to be a particular fascination of mine, which is why I want to start a discussion tomorrow of Jim Benford’s latest paper on beamed sails and how they might be optimized for both performance and cost. Reading through Benford’s work, however, I also came across Chris Wilson’s recent articles in Slate, which discuss Jim and Gregory Benford’s work on interstellar beacons and the SETI ramifications. I want to be sure to point to Wilson’s How to Build a Beacon because I don’t see ‘Benford beacons,’ as they’re increasingly called, discussed much in the media, and Wilson does a fine job at setting the concept in context.
Messages into Deep Time
The two part Slate series (the first article is The Great Silence) considers humanity’s legacy and relates it to the issues raised by SETI. The Arecibo message sent in the direction of the globular cluster M13 in November of 1974 is Wilson’s point of departure. Carl Sagan and Frank Drake set up the famous message in the form of 1679 binary digits that could be decoded into a set of simple pictures showing the image of a human being and other aspects of our existence including a double helix and a graphic of the Solar System. There is rudimentary content here, but the idea that such a fleeting signal would be received is dubious, given the odds on its happening to have a receptive civilization in its path in the first place. As Wilson writes:
Even if we left the Arecibo telescope squealing out its signal until its power ran out and its hardware rusted, there’s virtually no chance that the emanations would get anywhere in particular, and hang around long enough to be seen or heard. The only way we’ll make contact is if we can make a beacon that keeps going for millions or billions of years after we’re gone.
Two of the signals sent to nearby star systems by Alexander Zaitsev from Evpatoria show up as part of the same argument, the point being that for an interstellar beacon to be noticed, it has to transmit for a long period and be energy-efficient as well. By ‘a long time’ I mean potentially eons, because such a beacon might be set up as the final gift to the universe from a dying civilization, and it might not be found for millions of years. Enter the Benford brothers, whose work on cost-optimized beacons we discussed here in articles like A Beacon-Oriented Strategy for SETI (and you can use the search function to pull up other Centauri Dreams stories on this work).
Signature of a Cost-Optimized Beacon
If you’re building such a beacon, you’re naturally going to think in terms of efficiency, as the cost of delivering a powerful signal continuously over a vast period of time would be mind-boggling. An efficient beacon is one that would choose its coverage area carefully to optimize the chances of being heard, and one that would offer short pulses that recur over regular periods. Note what a departure such a signal would be from the kind of signal conventional SETI is optimized to find, its searches running quick sweeps past stars to find continually broadcasting beacons. A Benford beacon’s signature would be intermittent, a brief pulse that would eventually recur.
No technology available in the near-term will allow us to deliver powerful signals every minute of the day over a span of multiple epochs… But we might be able to make a beacon that works more efficiently, by targeting only those star systems where life seems most likely, and then pinging them each in turn, repeating the cycle every few months or so. Presumably, if a curious civilization caught one transmission, it would train its telescopes on that exact spot until the next part of the beacon’s message arrived. This more sensible approach—a sort of Energy Star specification for SETI—would save enough power to keep the beacon running for millions of years.
If we’re trying to receive such a signal, slow and steady scans of the galactic plane might turn it up in the form of a short narrowband burst that would eventually repeat, which would call for longer ‘dwell times’ — the time devoted to looking at a particular target — and a good deal of patience. Gregory Benford notes that a civilization building such a beacon in our system might locate it at roughly 0.5 AU, allowing for plenty of energy for the beacon’s solar cells. Such a beacon would also face the threat of space debris, given that we’re talking about an artifact that will need to survive for hundreds of millions of years — deep time — and remain functional. Advanced robotics are one way Benford sees to repair damage and keep systems running.
Monument to a Lost Civilization
Benford beacons get around the synchronicity problem that bedevils those obsessed with communication with extraterrestrial civilizations. We have no way of knowing the average lifespan of a technological culture, and it’s possible that such lifetimes are measured in mere hundreds of years or millennia. A long-term beacon keeps sending detectable signals long after the civilization that created it is gone, perhaps as a monument in the fashion of the pyramids. Wilson writes about the Star Trek episode called ‘The Inner Light,’ in which Captain Picard lives out an entire existence on an unknown planet as he experiences an alien mind-probe, only to come to the end of the message and awake to find that a mere 25 minutes have passed.
Would our own species build a Benford beacon if catastrophe loomed? It’s an interesting notion, and it gets around the concerns that some have expressed about METI (Messaging to Extraterrestrial Intelligence), in that a society that builds a ‘funeral pyre’ beacon isn’t even thinking about a response, whether dangerous or otherwise. Wilson suggests a kind of beacon insurance system — build an interstellar beacon that is programmed not to function unless it loses all contact from its creators for an extended period. If it determines the creating culture is extinct, it switches on to send out the valedictory. A civilization dies, but in the remote future, perhaps another detects and decodes its final thoughts. There’s a bleakness in the concept, and yet at the same time a certain degree of grandeur.
To explore Benford beacons at the source, see James Benford et al., “Cost Optimized Interstellar Beacons: METI,” available here, and Gregory Benford et al., “Cost Optimized Interstellar Beacons: SETI,” available here.
by Paul Gilster | Dec 7, 2011 | Astrobiology and SETI |
The on-again, off-again SETI search at the Allen Telescope Array is back in business as Jill Tarter and team focus in on some of the more interesting worlds uncovered by the Kepler space telescope and follow-up observations. You’ll recall that last April the ATA was in hibernation, having lost its funding from the University of California at Berkeley, which had operated the Hat Creek Observatory in northern California where the ATA is located. It took a public campaign to raise the funds needed for reactivation and new operations, as well as help from the US Air Force in the form of its own assessment of the ATA’s applicability in its space situational awareness studies, which include developing a catalog of orbiting space objects.
The SETI Institute, along with third-party partners and volunteers, has set up SETIstars.org as a fund-raising operation specifically targeting the ATA — it’s important to realize that getting the array back in operation is a first step in the larger process of meeting expenses for continuing work, so you’ll want to check in on SETIstars regularly to see how the campaign is going.
But back to the forthcoming ATA work on Kepler planets. The plan is to work through the Kepler discoveries, taking advantage of the fact that SETI now knows for a fact that the stars in question have planets. Thus Jill Tarter (SETI Institute):
“This is a superb opportunity for SETI observations. For the first time, we can point our telescopes at stars, and know that those stars actually host planetary systems – including at least one that begins to approximate an Earth analog in the habitable zone around its host star. That’s the type of world that might be home to a civilization capable of building radio transmitters.”
The worlds found in the habitable zone (here defined as the zone in which liquid water could exist on the surface) will receive priority, but the people behind the ATA are as aware of the dangers of preconceived notions as any of us, and if sufficient funding is found, all the planetary systems Kepler discovers will be examined across the 1 to 10 GHz terrestrial microwave window. The ATA’s ability to search across tens of millions of channels simultaneously gives it capabilities far beyond those of more common SETI work in limited frequency ranges.
Planets Around Massive Stars
Meanwhile, the Kepler Science Conference continues, with the program available online. And I don’t want to get deep into the Kepler conference without getting to the recent work at Caltech, where astronomers announced the discovery of 18 planets around stars more massive than the Sun. This work involved the Keck Observatory in Hawaii with follow-up work at McDonald and Fairborn Observatories (Texas and Arizona), focusing on ‘retired’ A-class stars more than one and one-half times as massive as the Sun. These so-called ‘retired’ stars are now in the process of becoming sub-giants. The planets were detected by radial velocity methods.
The planets here all have masses similar to Jupiter’s and represent a 50 percent increase in the number of planets known to be orbiting massive stars. What’s particularly interesting here is the wider orbits in which these planets are found. All are at least 0.7 AU from their stars, while a sample of 18 planets around stars like the Sun would turn up at least half of them in close orbits, the result of planetary migration. John Johnson (Caltech), first author of the paper on this work, says the question is whether gas giants around massive stars do not migrate in the first place, or whether they do migrate but are simply destroyed when they plunge into their stars. Also interesting is the fact that the orbits of these planets are primarily circular, while planets around Sun-like stars vary from elliptical to circular.
The authors see the new planets as further evidence supporting the core accretion model of planet formation, in which planets grow through the accumulation of small objects to ‘snowball’ into the resulting world. Stellar mass seems to be a crucial factor, which would not necessarily be the case with the gravitational instability model, in which knots of matter in the circumstellar disk collapse rapidly to form a planet.
From the paper:
[The] observed correlations between stellar properties and giant planet occurrence provide strong constraints for theories of planet formation. Any successful formation mechanism must not only describe the formation of the planets in our Solar System, but must also account for the ways in which planet occurrence varies with stellar mass and chemical composition. The link between planet occurrence and stellar properties may be related to the relationship between stars and their natal circumstellar disks. More massive, metal-rich stars likely had more massive, dust-enriched protoplanetary disks that more efficiently form embryonic solid cores that in turn sweep up gas, resulting in the gas giants detected today.
The paper is Johnson et al., “Retired A stars and their companions VII. Eighteen new Jovian planets,” accepted by the Astrophysical Journal (preprint).
by Paul Gilster | Dec 6, 2011 | Exoplanetary Science |
It’s fun to see Kepler-22b — an intriguing new world that lies 600 light years from us toward Lyra and Cygnus — being referred to as the ‘Christmas planet’ in the newspapers this morning, the latter a nod to Kepler chief scientist William Borucki, who said he thought of the planet that way, as a seasonal gift to the team. Borucki’s enthusiasm is understandable, and it’s echoed by Geoff Marcy (UC-Berkeley), who called the Kepler-22b work a ‘phenomenal discovery in the course of human history.’ I can’t argue with scientists of this calibre — with a surface temperature not so different from an April afternoon where I live, Kepler-22b can lay claim to being the smallest planet we’ve found orbiting in the habitable zone of a star like our Sun.
The host star is, in fact, a G5-class object with mass and radius only slightly less than that of our Sun, which is a G2, and the planet in question orbits it with a period of 289 days, some 15 percent closer to its star than we are to ours. Liquid water could surely exist on this object, and the excitement grows from that fact as well as the fact that this is the smallest-radius planet discovered in any habitable zone thus far. At 2.4 times the size of the Earth, it falls into the ‘super-Earth’ category about which we need so much more information. So far, we can say about its mass only that it is less than 36 times that of Earth (this is based on the absence of a measurable radial velocity wobble in the host star in follow-up observations). The mass of other ‘super-Earths’ has been measured at five to ten times that of Earth.
Image: This diagram compares our own solar system to Kepler-22, a star system containing the first “habitable zone” planet discovered by NASA’s Kepler mission. The habitable zone is the sweet spot around a star where temperatures are right for water to exist in its liquid form. Liquid water is essential for life on Earth. Credit: NASA/Ames/JPL-Caltech.
A second Earth? Hardly, but habitable conditions could exist here even if, as seems likely, Kepler-22b is more of a Neptune than an Earth, perhaps one with a planet-encircling ocean. But we have so much to learn — is this actually a rocky world, or an ocean planet or a kind of cross between Neptune and the Earth, with gas, liquid and plenty of rock? Whatever the case, Kepler-22 has been a long time coming, with the first transit captured just three days after Kepler became operationally ready. The all important third transit was acquired just about a year ago.
The Kepler science conference at NASA Ames is ongoing (it runs from the 5th to the 9th), and we now have an 89 percent increase in the number of planet candidates identified by the hard-working instrument, the total reaching 2,326. A NASA news release on the latest findings says that 207 of these candidates are approximately Earth-sized, while 680 fit the ‘super-Earth’ category, 1,181 are Neptune-size, 203 are similar to Jupiter in size and 55 are larger than Jupiter. The main trend here is a dramatic increase in the number of smaller planet candidates.
The new data show 48 planet candidates in their star’s habitable zone, a decrease from the 54 reported in February that is related to a slightly changing definition of ‘habitable zone’ in the new Kepler catalog. Natalie Batalha (San Jose State University) is Kepler deputy science team lead:
“The tremendous growth in the number of Earth-size candidates tells us that we’re honing in on the planets Kepler was designed to detect: those that are not only Earth-size, but also are potentially habitable. The more data we collect, the keener our eye for finding the smallest planets out at longer orbital periods.”
All true, and exciting in every respect. Still, I can’t help thinking how we keep finding new causes for celebration, each one with a slightly smaller world, or one just a bit more in the habitable zone than the previous. In my household we have a birthday tradition that stretches what would be a one-day event into a week-long affair. On my actual birthday, I’ll get presents from the kids. But maybe one of them couldn’t be there, so that sets up a second ‘birthday’ the next day. And then a day or two later we’ll go have a birthday dinner out. You get the point: It’s fun to drag out festivities, and we can expect more of this phenomenon as Kepler continues its work. Because one of these days it’s going to tag a planet of definitely Earth-mass in the habitable zone of a G-class star, and that’s going to be the true ‘second Earth’ we’ve all been hoping to find.
by Paul Gilster | Dec 5, 2011 | Culture and Society |
If we ever achieve manned missions to the stars, one of the assumptions is that we will find planets much like Earth that we might live on and colonize. But what if the assumption is flawed? There are surely many Earth analogues in the Milky Way, but we don’t know how widely they are spaced, and a near-miss isn’t necessarily helpful, as both Mars and Venus attest. People like Robert Zubrin continue to advocate terraforming as a solution for Mars, and it may well happen one day, but supposing we get to another star, would we have the moral right to terraform a world with living creatures on it, even if they didn’t meet our criteria for intelligence?
Robert Kennedy (The Ultimax Group), working with colleagues Kenneth Roy and David Fields, has been pondering these issues and went through a possible solution at the recent Tennessee Valley Interstellar Workshop in Oak Ridge. If we stop worrying about Earth analogues, a range of interesting possibilities open up, as our own Solar System illustrates. We have small planets like Mars, along with what may be a huge number of dwarf planets. We also have moons in a wide range of sizes around the gas giants. Suppose we could transform such worlds by building a spherical shell of matter around them, totally enclosing an atmosphere and living ecosystem?
Beyond the Habitable Zone
The idea seems outrageous, but Centauri Dreams readers are familiar with even more gigantic concepts like Dyson shells, engineering on levels that would require a Solar System-wide infrastructure and a Kardashev Type II-level civilization to build. If we extrapolate advancing technologies that can do gigantic things, we can consider creating an Earth-like environment (in most ways) under a shell that protects the inhabitants from radiation and provides a self-enclosed ecology. The question of a ‘habitable zone’ would disappear because artificial lighting and temperature control would be built in, and the wild card would be gravity, which would depend on which bodies were selected for enclosure. Most would offer gravity only a fraction that of Earth’s.
Kennedy and team wrote a paper for JBIS in 2009 that lays all this out. Working the math on spherical shells, they ponder the fact that if the objective is to contain a 14.7 psi Earth-normal atmosphere, such a shell would experience the same kind of pressure-induced tension found in a balloon. Assume one atmosphere of pressure at the underside of the shell and vacuum above it, and it is possible to choose a shell thickness so that the compressive stress of gravity cancels out the atmosphere-induced tensile stress in the shell. A shell made completely of steel, for example, built to enclose a world 20 kilometers above its surface, would need to be 1.31 meters thick if enclosing the Earth, and 8.05 meters thick if enclosing the Moon.
Moreover, the shell mass used is there simply to create compressive force — opposing the pressure of the atmosphere within the shell — and can be no more than dead weight. The authors figure that enclosing the Earth’s Moon could be done with no more than a 1-meter thick layer of steel if it incorporated 62 meters of regolith on top of it, with open-ended combinations of steel, ice, dirt and rock possible for the job:
It is not actually necessary to use a metal such as iron or steel. Stony materials such as concrete can handle a lot of compression. A strong fabric material that is airtight and in slight tension could be used to support the mass of the shell, which could be mainly rocks and dirt.
The authors contend that a shell with mass equally distributed across the surface of the shell will be stable with respect to the more massive body at the center of the shell:
If the central mass is displaced a given distance inside the shell, gravity will act to restore the shell’s original position with respect to that body. Such is not true for a ring. If there were no way to damp the movement, the shell would oscillate back and forth. A viscous atmosphere will tend to dampen oscillations until the mass center is once again congruent with the center of the shell.
The Riches of Ceres
Now consider the asteroid Ceres. Here the shell, depending on which mass estimate for Ceres we choose, would have to range (if made of steel) from 45.2 to 90.4 meters in thickness — this is the amount of mass that would be necessary to hold an Earth-normal atmosphere. This is one thick covering, providing enough shielding to survive a nearby supernova. Assume you have a terraformed Ceres that is half ocean and you wind up with enough dry land area to approximate the area of Indonesia, on a world where gravity is 1.5 percent that of Earth. Could a human colony survive in conditions of micro-gravity? At this point we simply don’t know the answer.
But think about the scenario for a moment. In an enclosed Ceres, climate is a design variable and lighting can be adjusted to approximate whatever day/night cycle the occupants desire. Imagine the underside of the shell as the urban area, a place where residents live in housing that overlooks the spectacular vista of the interior, which could be maintained as farmland or a nature preserve filled with whatever species the designers choose to introduce. With normal atmospheric pressures and light gravity, human-powered flight would always be an option. The outside of the shell would be devoted to heavy industry for manufacturing and power plants.
Taken to an extreme, we get this:
… the subterranean zones of small celestial bodies would offer vast – virtually unlimited – cubic for support functions and resource extraction. Consider that the interior of Ceres – half a billion cubic kilometers – could contain almost exactly the same working volume as a world-spanning city which packed the entire surface of Earth, oceans included, with billions of 1 km high skyscrapers, each the rival of Burj Dubai. In the light gravity of Ceres, every bit of that volume would be easily reachable and cheaply exploitable, unlike the deep wells and mines of Earth. A shell world might well be the richest planet in its solar system, once the huge cost of englobement was paid off.
Building for Safety (and Aesthetics)
Numerous dangers could beset a shell world, including many that already threaten our planet, such as the impact of large asteroids, but we could avoid some problems — volcanoes and earthquakes spring to mind — if we choose or build worlds without plate tectonics, and issues like solar flares would have little effect given the shielding the shell world’s inhabitants could rely on. A rupture in the shell would be a hazard, but a small shell world like Ceres would have a shallower gravity well than Earth and be less likely to draw in an asteroid. Moreover, any shell world would include the kind of planetary defense systems that a civilization capable of building the shell in the first place would be able to deploy. Shell maintenance, safety and improvement would doubtless be an ongoing project.
The paper works through one possible construction scenario involving the Moon and considers the massive amounts of energy required to move the needed terraforming materials (roughly one quadrillion tons), obviously requiring huge advances in energy production and space transportation. But it’s a fascinating vista, one that sees the creation of hanging cities on the underside of a shell that represents an area equal to four times the area of the United States. The surface of the re-made Moon can be tuned up to be as Earth-like as we choose to make it, the entire project taking hundreds and more likely thousands of years to see to completion.
The presence of hanging cities will diminish the required surface loading by inert material. Lighting would be artificial, with solar energy (assuming the shell world is near a star) powering up the lights, or power plants on the surface of the shell doing the job if the world were built in deep space. The paper argues that shell worlds all the way out to the Kuiper Belt could have an Earth-like insolation, ecology and diurnal cycle. And imagine this:
Existing electro-luminescent displays (ELD) only provide about 1-2 W/m2 of radiant energy in various colors from red to blue-green, but their state of the art (brightness, efficiency, cost) is rapidly advancing… Since ELD materials are presently available in all three primary colors and can be subdivided into addressable segments, we can imagine a pixelated ceiling of video wallpaper simulating the natural sky of Earth (clouds, sunsets, stars, etc.) or generating any arbitrary scene. The postindustrial motto “everything is media” means art can reach its fullest expression in the canvas of a shell world.
If we do become the Type II civilization capable of building such structures, we’ve not only opened up numerous worlds within our own system for colonization, but have also gained the experience needed for constructing stable generation ships for long-duration interstellar flight. And because shell worlds could be located anywhere a suitable moon or planet is found, we should consider the possibility that alien civilizations may already have constructed such worlds around red dwarf stars or even brown dwarfs, which may outnumber all other kinds of stars. The traditional concept of a habitable zone may not be the marker we’ve always assumed it to be, with prospects for SETI extending to worlds that would not before now have gained our attention.
The paper is Roy, Kennedy and Fields, “Shell Worlds: An Approach to Terraforming Moons, Small Planets and Plutoids,” JBIS Vol. 62 (2009), pp. 32-38. If you’re a science fiction writer in search of a setting, you must read this paper. I’ll also let everyone know when the Oak Ridge presentations become available online so you can see Robert Kennedy’s talk and slides.
by Paul Gilster | Dec 2, 2011 | Culture and Society |
Les Johnson (MSFC) always says that the coolest job title he ever had in his long career at NASA was Manager of Interstellar Propulsion Research. Think about it — if going to the stars is your passion and you have a title like that, you must feel that you have really arrived. These days he goes by the more prosaic title of Deputy Manager for the Advanced Concepts Office at Marshall Space Flight Center in Huntsville, but as the recent interstellar workshop in Oak Ridge demonstrated, he’s also ranging widely on his own as conference organizer, author and science fiction aficionado. His presentation in Oak Ridge was designed to jump start the conference with a survey of the problems of interstellar flight and the long list of possible propulsion solutions.
The Interstellar Conundrum
The problems are clear enough. Think of the distance between the Earth and the Sun (about 150 million kilometers). That’s 1 astronomical unit (AU). Shrink that distance to one foot and imagine the Solar System, with Neptune 30 feet out and so on. On that scale, the distance to the Alpha Centauri system is 47 miles. Moving at 17 km/sec, Voyager 1 would take 74,000 years to make the Centauri journey (if it were pointed in that direction in the first place, which it is not). Les was part of the Interstellar Probe Science and Technology Definition Team that aimed at designing a spacecraft that could reach the heliopause, and at this point in our technological evolution (this was back in the 1990s), it was clear that three propulsion options were possible: A chemical rocket with gravitational slingshots at both the Sun and Jupiter, solar sails, or nuclear electric.
Let’s pause on the latter. Electric propulsion, which uses electrical energy to heat and eject the propellant, offers much lower thrust levels than chemical propulsion, but it is ten times more efficient per pound of fuel. A mission to the outer system would require a nuclear power source operating at high power, but the technology is workable and in Les’ opinion could deliver a mission to 200 AU within 20 years of launch. Solar sail options are likewise no longer theoretical, and Les pointed out that NASA has selected L’Garde to work on a sail a bit less than 80 meters to the side that is to become the agency’s first deep space sail experiment in about three years.
From nuclear pulse propulsion (Project Orion, the size of an aircraft carrier, would present serious problems in terms of in-space assembly) to nuclear fusion and antimatter-catalyzed fusion, a variety of nuclear concepts have been considered, including the British Interplanetary Society’s Project Daedalus and the ongoing Project Icarus studies. Antimatter remains an elusive goal. We would need antimatter production of just kilograms per year to drive a true interstellar mission (compare this to tens of thousands of tons of helium-3 and other fuels needed for a Daedalus), but our current antimatter production is mere nanograms per year.
The Q&A session that followed Les’ talk brought a response to his contention that fission was not practicable for interstellar travel, noting that staged fission rockets might be able to reach 2 percent of lightspeed. If so, that does change the picture somewhat, and if anyone has a reference to a paper on staged fission concepts, I’d like to read more about this. Another interesting note: Les’ book Going Interstellar, edited with science fiction writer Jack McDevitt, is coming out from Baen some time in 2012. This is a collection of essays and fiction, and it was great to hear that the publisher intends to bring out a teacher’s guide to get these ideas to high school students. We need to energize that next generation.
Pushing into the Artistic Frontier
C Bangs is a Brooklyn-based artist whose work draws on a vision of man’s future in space. I use the term ‘vision’ with care, because I find her work laden with mythic echoes of our species’ past even as it points to a cosmic destiny that we seem impelled by our nature to strive for. I’ll add this: My own background as a medievalist left me with a fascination for illuminated manuscripts like the Lindisfarne Gospels and the Icelandic Flateyjarbók. Some of C’s work reminds me of ancient manuscript designs even as it draws on cutting-edge physics and astronomy, subjects she has illustrated so well in her collaboration with her husband Greg Matloff. If you page through a book like Solar Sails or Paradise Regained, you’ll see how her work re-states the scientific themes with archetypal resonances that take the reader into the realm of the transcendent.
Image: Green Man & NGC #4414. Credit: C Bangs.
The Paradise Regained book is particularly to the point here, because as C told the audience in Oak Ridge, she has long been fascinated with the Gaia Hypothesis, the concept that the Earth as a whole is a cooperative system that maintains conditions for its own survival. You can wed this deep interest in interlocking systems with a love of landscape that was surely nurtured by trips to Puerto Rico, where her father was teaching. One of these trips led to a tour of the great Arecibo dish, an experience that was both majestic and transformative. From then on, cosmology would weave into mythology as the basis for her vision. Her work for NASA includes a holographic coating technology that could enable 3-D images to accompany deep space missions (a set of her holographic work is housed at Marshall Space Flight Center).
What struck me as C showed images of her work in Oak Ridge was the sense of optimism they contained. If she explores human consciousness through archetypes, she also insists on a positive response to the cosmos and an engagement with cutting-edge ideas. It’s no surprise that interstellar studies champion Robert Forward was a key figure in securing her early funding from NASA, and her continuing work with Greg has ensured that she keeps current with the interstellar community. Optimism may grow naturally out of that engagement, the idea being that without a frontier to explore, the problems of this planet can seem overwhelming, leading to a cynical, defeatist kind of art that is worlds away from what C expresses. Our problems are indeed huge, but space offers solutions to our resource crisis and feeds our need for exploration, the latter a deep-seated drive so well captured in C’s eloquent imaginings.
Image: Leopard Ceremony & Eagle Nebula. Credit: C Bangs.
Project Icarus: Pushing Designs to the Edge
People sometimes say that Project Icarus has a strange name, given that Icarus was a mythological figure who flew too close to the Sun and thus met his doom. But Icarus is also a logical name for the project that would follow up the 1970s-era Project Daedalus, which had been the first detailed design study of a starship ever made. After all, Icarus was the son of Daedalus, and as Richard Obousy pointed out in his presentation in Oak Ridge, the idea is that Icarus was a pioneer who pushed his technology to its limits to reveal its hidden flaws. Project Icarus aspires to do the same, to push a fusion design hard to uncover hidden problems, and determine just how much we have advanced since the heady days of Project Daedalus.
Now Richard Obousy is as engaging a proponent of interstellar flight as one could meet, and we enjoyed a lengthy dinner conversation after the day’s sessions were over. Every now and then I talk in these pages about teaching tools, the kind of comparisons that help us understand things like interstellar distances. Rich had one for me — Look at a map of the United States and imagine that the Earth is in New York City, while the Alpha Centauri stars are in Los Angeles. With that scale in mind, realize that our Voyagers, now entering the heliopause, would be roughly 1 mile along the route to LA. What we need to do, as Rich told the audience during his talk, is to increase velocity by a factor of about a thousand, to make missions consistent with human lifespans. Icarus chooses fusion as the best way to liberate the energies needed for that.
Image: Project Icarus arriving at a destination system. Credit: Adrian Mann.
The Project Icarus playbook is a thing to behold, with twenty different research areas under active investigation, everything from primary propulsion and fuel to power systems, communications, computing, vehicle assembly, risk and repair. Each of these modules has a lead and each lead has a team dedicated to solving the challenges of his or her subject. The purpose is not to build a starship — we’re a bit ahead of the curve for that — but to motivate a new generation of scientists to become involved in interstellar studies, to generate interest in precursor missions, to explore credible design concepts and assess the maturity of fusion.
The 100 Year Starship Study DARPA has funded will be making an award of $500,000 to the team it chooses to advance interstellar ideas in coming years — both the Icarus team (operating as Icarus Interstellar) and the Tau Zero Foundation have submitted proposals, along with a number of other organizations. We won’t know who wins the grant for a few months yet, but ponder the overall ideas. As Obousy told the audience in Oak Ridge, the average lifespan of a company in the United States is 13 years. What DARPA wants to do is provide seed money for an organization that will last for centuries. That in itself is perhaps a bigger challenge than building a starship. It involves an attempt to find the next Google, the next Apple, and to so craft the organization that it can survive economic ups and downs and changes in intellectual fashion.
Can it be done? The DARPA award-winner will make the effort, one that Centauri Dreams heartily applauds because it requires long-term thinking pushed to its limits, and shrewd marshaling of existing resources. Interstellar studies is an exciting place to be. We’ll talk on Monday about another exciting concept called ‘shell worlds’ that I learned about in Oak Ridge, and discover why little Ceres may one day be the richest world in the Solar System.
