Centauri Dreams
Imagining and Planning Interstellar Exploration
Visualizing Vessel
In his first article for Centauri Dreams, Heath Rezabek described an installation design called Vessel that we might develop to mitigate near and long term risk. The essay explained why we should pursue practical strategies to avoid the permanent stagnation of society in case of catastrophe, and described the need for enduring educational facilities to forestall a flawed realization of our potential over time. The Vessel proposal involves the deliberate engineering of resilient and flexible facilities dedicated to the retention of humanity’s legacy as an ongoing hedge against what he calls Xrisk. In this second article, Heath makes a case for the importance of visualization in the early stages of any long term project — whether terrestrial or beyond — as a strategy and tool for focusing enthusiasm on the long work of system design.
by Heath Rezabek
Cory Doctorow, author and open source advocate, has said that if we want to change the future, we need to change the stories people tell themselves about it. As discussed in my first article on the Vessel proposal, culture is well accustomed to visualizing dire possibilities, particularly those of Xrisk subtype Permanent Stagnation. Yet if all you have is a hammer, everything looks like a nail. If the predominant vision of the future is one in which we fail to achieve our full potential, then at the least this fact won’t help our efforts to build the wherewithal to achieve something more enduring.
Figure 1 – Stephan Martiniere (http://www.martiniere.com) – Selected to accompany a not-yet-published space.com interview – Used by permission
Because they can set trajectories and influence the tone of ongoing efforts, visualizations — even early on in a project — can be very potent, and important to conveying an understanding of the project’s potential. This realization was also behind the first FarMaker Speed Sketch contest, successfully carried out for Starship Congress 2013. Children, enthusiasts, and professional concept artists competed for prize money and recognition, painting and drawing and rendering speed sketches of starships, based on the Daedalus theme. (Speed sketches are a genre of concept art common throughout the entertainment and visualization fields, where rapid techniques are used to express the energy and essence of an idea in a visual form.)
At the moment, from our vantage point of stalled or listless efforts, cultivating new visions of an interstellar future may not make much sense to the broader public. But years from now, as our capabilities and motivations for action grow, (and presuming we endure) these efforts may prove key in sparking forward momentum. If this is true of interstellar aspirations, perhaps it could be true of Earthbound aspirations as well. The most pressing aspiration at hand is the drive to build — or even to see for ourselves and our world — a future in which Earth-originating life achieves its full potential. Of course, ideas and techniques applied in one area (such as the Vessel project) can be applied in other areas (such as eventual starship design), and vice versa.
The phenomenon whereby vividly articulated visions of alternate futures helps pave the way for their realization is not a new one. From Leonardo da Vinci to Jules Verne and on to our present day, we’ve long been aware that the inventions of the mind can unfold in the world when expressed for others to perceive. But currently, there is particular and renewed interest in describing and modeling future possibilities as thought experiments to test their viability. One term for this approach is Design Fiction; another is Science-Fiction Prototyping. Doctorow made the observation cited above in discussion with Brian David Johnson, as part of his work with sci-fi prototyping. Bruce Sterling has an extensive archive of writings on Design Fiction in its present form. At Arizona State University’s Project Hieroglyph, science fiction authors such as Neal Stephenson, Geoffrey Landis, Bruce Sterling, Cory Doctorow, and others explore the potential for speculative ideas to shape reality.
We’ll return to these related strategies in future installments. For the moment, however, we’ll stay focused on the basic power of concept art and visualizations for both informing and inspiring others, when working with a speculative proposal or technology. In the case of the Vessel project, my experience of the power of visualizations to clarify and galvanize understanding came early. At 100YSS 2012, for the first presented version of the Vessel proposal, I discovered that the single most effective element of my presentation turned out to be the visualization of the Lilypad seasteading habitat, designed by Vincent Callebaut. This visual anchor, once linked with the dedicated task of housing archives and labs, immediately sparked in session attendees a sense of form and function for the Vessel proposal.
Figure 2 – Vessel as an instance of Vincent Callebaut’s Lilypad seasteading habitat, 100YSS 2012 and Starship Congress 2013.
Figure 3 – Vessel as an instance of Vincent Callebaut’s Lilypad seasteading habitat (Cutaway and Details)
Upon seeing these slides, viewers later said, they had an instant sense of the proposal, and immediately understood more clearly what I meant (and didn’t mean) by a Vessel archive. This understanding was not merely important for building comprehension, or even for support. It also helped to set tangible limits to the problem space we were exploring, and the design solution I was proposing. A self-contained habitat may or may not be closed-loop; but in any case it is not in itself a sprawling city. If anything, it might be a facility within that city, or even a campus or complex within that city; but it had limits and an overall, centrally-focused, form. A Vessel habitat could easily be envisioned as a module on a starship, or an orbital station, or an Arcology (as per Paolo Soleri), or other similar forms.
Figure 4 – Arcology, architectural ecology: The city as space station, envisioned by architect Paolo Soleri, 1969.
These design limits help shape the debate: How do you provide energy to such a habitat? Are there technologies not viable on a very large scale which could be used for smaller, mission-critical facilities? What is its likely maximum scale or size? Importantly, what would it look like if different versions were built in a variety of settings?
For Starship Congress, I decided to visualize a Vessel installation in a few more forms. The goal was to express that a Vessel could be “massive as habitats, with others more like sculptures, compact and dense as a room.” One goal for 2014 is to develop the Vessel Open Famework, a Creative Commons (CC BY-SA) document which would sketch out the fundamental aspects and design patterns for a Vessel installation, in such a way that others could evolve and adapt them to fit their unique requirements. So, for the first time, I began to sketch out first guesses at functional schematics: What functions were key and core, and what types of spaces did they imply? The idea that outer layers would be (in the near term) public-facing and fairly welcoming, while inner spaces would be highly specialized and include mission-critical archives, had been there since 2012. Yet the idea of an Open Framework — as a practical, realizable working document available for anyone to adapt — evolved from this task of identifying a minimal set of functional spaces, each forming and informed by its neighbors.
Figure 5 – Vessel Open Framework: Draft functional schematic, Starship Congress 2013
Open Source is an often-misunderstood form of intellectual property. Creative Commons does not prevent the creator from selling or making a profit from their work. The extent of shared content is flexible and depends on the license chosen. The preferred license for the Vessel framework, the CC BY-SA License specifies that you can do whatever you like with the design, including commercialize any results or adaptations, so long as you also pass on the right to do the same to those who next encounter your own derivative work. This flavor of open licensing does not negate the ability to commercialize, but rather removes any artificial scarcity from its core value so that the original design can be applied as widely as possible, and its true value determined.
From the perspective of Xrisk mitigation, aiming for open source distribution of the core framework has been a simple, nearly inevitable, decision. Earth-originating life faces a variety of complex challenges having complex causes; it stands to reason that partial solutions may be found across many different domains. Because we cannot know where risk-mitigating solutions will be pieced together from, and because the stakes are so high, it is essential to remove barriers to sharing and access wherever possible. The stakes at work when dealing with Xrisk define a large playing field. On that field, eventually, open source of some kind or another is an inevitable development if we are to truly test our most viable strategies as widely as possible.
With a document sketching out the Vessel Open Framework firmly in mind as a goal for 2014, I wanted to offer up a simple but compelling baseline design to speed future work. I wanted a simple shape and form which said to others, ‘This is a very simple starting point, which is probably not ideal for a final architecture, but which is intriguing enough to spark new interpretations.” The shape and form which resulted is that of a simple cube, tilted and sunk halfway into the groundplane, so that three overhanging entries are visible, a peak (perhaps housing communications or power arrays) is clear, and the iceberg-like sunken mass of half the structure underground is implied, just waiting to be explored. While it bears a passing resemblance to the pyramid, these other implications (understories for deep archives; three enties into three collections based on nature, science and culture) are also there to be inferred.
Figure 6 – Cubic Vessel
While I had developed this concept before Starship Congress, I did not have the wherewithall to realize images of this shape before the presentation. Upon returning home, I set to work with two artists I had come to know in the months leading up to the event. Together, Mark Rademaker and Joshua Davis have yielded some intriguing first glimpses of this strawman shape for further development. Pictured below, these rough first versions need one key preface: By the time we set to work, I had become excited by the possibilities of beamed solar power as a dedicated source due to several sessions at Starship Congress, but I had no clear idea what working beamed solar would look like. Additionally, I had become curious (during Day 1’s discussions of beam riders) about the question of whether communications and power / propulsion could be carried on a unified beam, and all of this collided in some very romanticized beaming in the first Cubic Vessels below.
Figure 7 – Cubic Vessel with Naive Beamed Solar Power and Communications Signal – Mark Rademaker
Figure 8 – Cubic Vessel with Naive Beamed Solar Power and Communications Signal – Joshua Davis
In discussions with Lt. Col. Peter Garretson, who delivered an inspired talk at the end of SC Day 3 in which beamed solar figured prominently, I was led to some more realistic interpretations of beamed solar power in the near term. (See below.) While not central to the Vessel Open Framework, the idea of dedicated energy is compelling enough as a backup or failsafe to be well worth visualizing realistically. A discussion of dedicated power for a Vessel facility is planned for future installments.
Figure 9 – Solucar – Concentrated solar receiver (Wikimedia Commons)
Figure 10 – Gemasolar – Concentrated solar receiver (Wikimedia Commons)
Figure 11 – Cubic Vessel with Concentrated Solar Receiving Beacon – Joshua Davis
From a growing understanding that these visualizations will be continually refined, we have begun to move towards more flexible frameworks. No visualization is final, and we continue to try new ideas as we gather resources on proposals for long term archives, and the sustainable societies which would be gathered there to miantain them.
Below is pictured Joshua Davis’ recent rendering of a lunar vessel, its receptor at the peak and its habitats built beneath the lunar surface, below a massive reflective array which nourishes the mission-cricitcal collections of the Vessel itself.
Figure 12 – Cubic Lunar Vessel with Concentrated Solar Receiving Beacon – Joshua Davis
Onwards we move, slowly building a unified design pattern language for the Vessel project, visualizing as we go. An inspiring image, even of something impossible here and now, can move the mind to spot new connections and bring them to bear on the problem at hand. In future articles, we’ll continue to explore other aspects of this work, such as discussions with Lt. Col. Garretson on potential locations for Vessel infrastructures, correspondence with USD’s Danieh Sheehan on the viability of hardening a Vessel’s power infrastructure against massive solar events, and the practical question of how we might build one using existing technologies if we had (say) 24 months til critical need.
For now, I welcome comments and reflections on the hypothesis that where vision and visualization leads, the mind and will can often follow.
SETI: Looking for von Neumann Probes
In a recent paper outlining a novel strategy for SETI, Michael Gillon (Université de Liège) makes a statement that summarizes what Robert Forward began saying back in the 1970s and even earlier. Interstellar flight is extraordinarily difficult, but not beyond the laws of physics:
Our technology is certainly not yet mature enough to build a probe able to reach one of the nearest stars in a decent time (i.e. within a few decades), but nothing in our physical theories precludes such a project. On the contrary, the constant progress in the fields of space exploration, nanotechnology, robotics and electronics, combined with the development of new possible energy sources like fusion reactors or solar sails, indicate that interstellar exploration could become a technological possibility in the future, provided that our civilization persists long enough.
That last issue about the survival of our society is the L variable in the Drake equation, referring to the lifespan of any technological civilization. We don’t, alas, have any idea what its value is, which means we have no assurance going forward that any civilization can expect to have a lifetime long enough to explore the stars. Finding another functioning technological society would give us hope that such entities don’t necessarily destroy themselves.
But Michael Gillon is after other game in this new paper, titled “A novel SETI strategy targeting the solar focal regions of the most nearby stars.” After running through the Fermi question and noting that self-replicating interstellar probes of the kind posited by John von Neumann could fill the galaxy within, at most, hundreds of millions of years, Gillon asks whether any such probe in our own Solar System would be detectable. He’s interested in the question of communications and invokes the Sun’s gravitational lens, first discussed by Von Eshleman in terms of astronomy and richly examined by Claudio Maccone, as the key to how any interstellar probes would communicate.
Just how big a difference the use of a gravitational lens could make is outlined in Maccone’s Deep Space Flight and Communications (Springer, 2009) and an earlier paper (see The Gravitational Lens and Communications). Bit error rate, a measure of the quality of a radio signal, becomes problematic (to say the least) if we try to communicate with a probe at Alpha Centauri with existing technologies like the Deep Space Network. But a communications relay at the Sun’s gravitational focus — 550 AU and beyond, depending on the wavelength we want to work at and the need to avoid the Sun’s coronal effects — would radically improve the situation.
In fact, Maccone has shown that at 32 GHz, the combined transmission gain brought by using this kind of link between the Sun and Alpha Centauri is 1016, making it possible to communicate with such a probe using only low power transmitters. A mere forty watts of transmitting power produces an all but flawless bit error rate, and the situation improves even more radically if we assume a relay at Alpha Centauri’s own gravitational lensing distance. Flawless communications then become possible at a power of less than 10-4 watts using the two 12-meter spacecraft antennae Maccone plugs into his assumptions.
Image: Pulled from the cover of Claudio Maccone’s book, this image shows his proposed FOCAL probe with antennae deployed, ready to take advantage of the Sun’s gravitational lensing.
But assuming a communications relay somewhere between 550 AU and 1000 AU in our own Solar System, the work of a self-reproducing interstellar probe, how could we go about finding it? Gillon looks at traditional techniques of optical imaging and stellar occultation but finds that they would probably not be able to turn up so small an object — he assumes an antenna with a diameter of no more than one or two dozen meters — so he suggests looking for ‘leakages’ in any traffic between the two systems (he uses Alpha Centauri purely for illustrative purposes):
Attempts to detect the hypothesized ICD [interstellar communications devices] can still be performed now, basing on the very purpose of the device: not only to receive messages from Alpha Cen, but also to send messages to Alpha Cen and to one or several probes orbiting the Sun. An intense multi-spectral monitoring of the focal region of Alpha Cen with, e.g., the Allen Telescope Array, could in principle detect some leakages in these communications, depending on the used technology, communication frequency, and emission power.
Underlying the search is the hypothesis that self-reproducing probes would be unlikely to communicate with their original stellar system, wherever it happened to be. More likely is that communications would be networked among nearby stars. Gillon goes on to say:
A communication strategy based on direct connexions between neighboring systems would be a much better solution, with the extra-benefit that the information gathered by probes would be spread among their whole network, without any loss even in case of collapse or migration of the original civilization. The first part of our hypothesis is thus that the envisioned probes would use this direct communication strategy.
A galaxy fully colonized by self-reproducing probes should, in Gillon’s view, produce an interstellar relay in the focal region of at least one nearby star, leading to a series of SETI searches looking for incidental radiation from these devices. It’s an interesting notion (and I am much in favor of fully exploring the gravitational lens and its implications), but it’s hard to see how a civilization able to build interstellar probes and the communications tools to support them would be unable to shield its technology from detection if it chose to do so.
The paper is Gillon, “A novel SETI strategy targeting the solar focal regions of the most nearby stars,” accepted for publication in Acta Astronautica (preprint).
Exoplanet Cloud Patterns Observed
Considering how much data it has accumulated, the Kepler mission will continue to serve us even if its ongoing operations have ceased. We’re now seeing some of its data used in conjunction with observatories like the Spitzer space telescope to tease out further information. Combine the two and we can examine distant worlds at multiple wavelengths, leading Paul Hertz, director of NASA’s Astrophysics Division, to say “We’re at a point now in exoplanet science where we are moving beyond just detecting exoplanets, and into the exciting science of understanding them.”
Exciting indeed, for what this multi-wavelength look has now provided is a low-resolution view of the clouds on one of Kepler’s earliest finds, the ‘hot Jupiter’ known as Kepler-7b. Spitzer has already proven its capabilities by producing temperature maps of exoplanets, but this is the first time we’ve been able to map cloud structures. The visible light Kepler observations had revealed a bright spot on the planet’s western hemisphere, but it took Spitzer’s infrared studies to show that astronomers were seeing light from the star bouncing off cloud tops rather than heat.
Image: Kepler-7b, shown in the artist’s conception at left, is the first exoplanet to have its clouds mapped, thanks to data from NASA’s Kepler and Spitzer space telescopes. The alien planet is 1.5 times as wide as Jupiter, which is shown at right for comparison. Credit: NASA/JPL-Caltech.
The planet itself is a relatively low mass ‘hot Jupiter’ orbiting its star in 4.89 days, with a radius large enough to indicate an extremely low density — in fact, this JPL news release describes the world as one of the puffiest planets known, light enough to float if somehow placed in water. Working with its albedo (average reflectivity) is tricky because distinguishing between reflected light and thermal emission is complicated by the heavy irradiation the planet receives from its star. But temperature readings in the range of 1100 to 1300 Kelvin are not hot enough to explain what Kepler had observed by studying the planet’s phases in visible light.
The asymmetry that Brice-Olivier Demory (Massachusetts Institute of Technology) and team are seeing in Kepler-7b’s light shows a structure that does not follow the temperature profiles of tidally-locked gas giants that have been observed before. There we would expect an eastward shift (east and west are measured from the substellar point of this tidally locked world, directly facing the star). The paper on this work explains the result (internal references omitted):
This eastward shift is consistently produced from a range of general circulation models for tidally-locked hot-Jupiters forced using various methods, including Newtonian cooling, dual-band radiative transfer or multi-wavelength radiative transfer. Combining these results with the analytical theory of Showman & Polvani (2011) suggests that thermal phase curve eastward shifts are robust outcomes of the hot Jupiter circulation regime.
And this is where Spitzer comes in:
As we do not detect thermal ?ux from Kepler-7b with Spitzer, the most likely conclusion is that the westward shift in the visible phase-curve is indicative of a variation in the cloud properties (cloud coverage, optical depth, particle size distribution, vertical extent, composition, etc.) as a function of longitude, governed by the planet’s wind and thermal patterns.
In other words, clear skies in the east, with high clouds in the west. And that picture should last. Few giant planets reflect as much light as Kepler-7b, and the paper makes the case that this is the result of stable clouds in the upper atmosphere. The tidally-locked world shows a climate that changes little over time, with cloud patterns remaining more or less constant. Although this ‘map’ of the planet’s cloud cover is extremely low-resolution, it marks a useful step as we continue to study the atmospheres of exoplanets, with the goal of applying such techniques to ever smaller worlds once we have the needed resources to work on planets more like Earth.
The paper is Demory et al., “Inference of Inhomogeneous Clouds in an Exoplanet Atmosphere,” accepted by the Astrophysical Journal and available online as a preprint.
Voyager in Perspective
Joseph Green worked for 37 years in the American space program, retiring from NASA as Deputy Chief of the Education Office at Kennedy Space Center. His specialty was preparing NASA fact sheets, brochures and other semi-technical publications for the general public, explaining complex scientific and engineering concepts in layman’s language. Joe is the author of over 20 science papers for NASA and contractor executives, but I ran across him decades ago through his novel The Loafers of Refuge (Ballantine, 1965), a paperback that sits on my shelf not three feet from where I’m writing. Joe’s five science fiction novels, which include Star Probe (1976) and Conscience Interplanetary (1972), are complemented by about 80 shorter works, and he remains active writing for online magazines, with recent stories in the February and May 2013 issues of Perihelion Science Fiction. As Joe explains, 31 years at Kennedy Space Center puts a wonderful spin on recent events. Sometimes the future happens faster than we think.
by Joseph Green
Not long ago the morning paper carried a front page though below-the-fold story to the effect that space scientists, working from accumulated and analyzed data, have finally agreed that the Voyager I spacecraft entered interstellar space on August 25, 2012. Up until now the exact time has been a matter of dispute. The spacecraft is still operating, and expected to have enough power to keep sending back reports, from at least one sensor, until about 2025.
In 1977 I manned a console as a member of the Atlas/Centaur launch team. I also prepared the A/C technical documents, including the “NASA Fact Sheet(s)” distributed in advance of each launch. These were a compilation and distillation of the most important basic data on both spacecraft and launch vehicle. They were carefully written for the layman, explaining the mission in terms understandable to most high school juniors. I inaugurated the series, and they became very popular with non-technical Kennedy Space Center personnel, the general public, and in particular the news media (the last for obvious reasons — a lot of their work done for them).
Although I wasn’t a member of their teams, the Delta and Titan/Centaur managers tasked me with preparing Fact Sheets for their missions as well. The much larger and more powerful Titan/Centaur had been chosen as the launch vehicle for the Voyagers because of the weight of the (at the time) highly sophisticated robot explorer, and the unusually high velocity needed to reach Jupiter in 18 months.
After a close-up exploration of Jupiter and several of its moons, Voyager I went on to Saturn for another flyby, then headed into interstellar space. The last was basically frosting on the cake, as was the photo Voyager I took on February 14, 1990, looking back at the Solar System (showing Earth as a “pale blue dot”). The two most important mission objectives had been successfully accomplished. Few expected this hardy explorer to still be functioning and reporting back when its escape velocity of 17 kilometers per second (in relation to the Sun) took it into interstellar space. But it’s there, and with another decade (hopefully) of life expectancy.
Image: The Voyager missions with their direction of flight indicated. Credit: NASA/JPL.
The journeys of the Voyagers have been reported here on Centauri Dreams and widely discussed in other media. For me, they trigger reflection and thoughts on perspectives. Mine is that of a teenager reading science fiction in the 1940s, never dreaming that mankind would land on the Moon in my lifetime (2050, perhaps?). And sending a robot into interstellar space was in the far, far future, something my great-grandchildren might try. And yet I not only lived to see both, I actually played a small role in these two great scientific adventures. Those of you growing up at a time when you rather expected to see men walking on the Moon, or robots reporting back from interstellar space, may have an entirely different perspective.
Sometimes the glamor and excitement of manned space flight tends to overshadow the accomplishment of the Voyagers, Pioneers, and other doughty robotic explorers. But in many ways unmanned spacecraft have contributed more to our knowledge of the solar system, and galaxy/universe than the manned programs. We’ve now had robot explorers do close-up, highly instrumented flybys of all eight planets, and one is on its way to the disenfranchised Pluto/Charon system. These accomplishments, it seems from this perspective, are worthy of more respect than they have received from the world at large.
100YSS: Building Tomorrow’s Instruments
The timing of the announcement that Voyager 1 has, for some time now, been an interstellar spacecraft came just before the 100 Year Starship Symposium and was certainly in everyone’s thoughts during the event. Jeffrey Nosanov (Jet Propulsion Laboratory) reminded a Saturday morning session led by Jill Tarter that when the Voyager program was conceived, the notion of going interstellar was the furthest thing from the planners’ minds. Voyager’s adventures beyond the heliopause are what Nosanov now calls ‘almost a completely accidental mission.’
How to follow up the Voyager success? For one thing, we already have New Horizons on its way to Pluto/Charon, with flyby in 2015, and I’ve already discussed the New Horizons Message Initiative, which would upload the sights and perhaps sounds of Earth to a small portion of the spacecraft’s memory after its encounters are done (see New Horizons: Surprise in Houston for more). But Nosanov asked Voyager project scientist Ed Stone, himself all but legendary in his association with the spacecraft, what he would like to see happen next. Stone said he’d like to see ten or a dozen spacecraft sent out in different directions to the same distance.
Image: JPL’s Jeffrey Nosanov, whose work now includes a study of next-step missions beyond Voyager.
Nosanov’s recently accepted proposal to NASA’s Innovative Advanced Concepts (NIAC) Program will examine just that scenario. What he plans to do is to design a spacecraft architecture that will probe what the project description calls ‘ the unique regions of the Heliopause, known as the nose, sides, tail, north and south.’ Flybys of the outer planets and Kuiper Belt objects as well as studies of the heliopause itself are what Nosanov has in mind, but he goes still further, looking toward reaching the Sun’s gravitational lens at 550 AU and beyond to study imaging of the center of the galaxy and other targets at various wavelengths.
State of the Universe
Speaking of working at various wavelengths, the morning “State of the Universe” session began with project scientist Adrian Tiplady discussing South Africa’s role in the Square Kilometer Array, itself a multi-national collaborative project whose 3000 small dishes will carry ten to one hundred times the traffic of the global Internet at any one time. The MeerKAT installation is a precursor for the full array, one whose 64 dishes will make it the largest radio telescope in the southern hemisphere until the Square Kilometer Array is completed some time in 2024. Extending across a number of African nations and into Australia, SKA will be fifty times more sensitive than any other radio instrument, a huge challenge in engineering as well as collaboration.
The State of the Universe panel was a lively session, held in the Hyatt’s ballroom and sparked by an enthusiastic Hakeem Oluseyi (Florida Institute of Technology), who offered an overview on our attempt to find dark matter and a whirlwind tour of the early universe following the Big Bang. Oluseyi sees the universe as a place that selects for life-forms that populate the cosmos because planetary existence is sharply limited by extinction events and resource depletion. “Intelligence is needed to move into space,” he added, “but the window of opportunity is finite. Single cell life-forms survive out of robustness, but complex beings need to exploit resources to move into space. Every life form on every planet is in a space race.”
Image: Florida Institute of Technology’s Hakeem Oluseyi, whose rapid-fire tour of the early universe challenged the skills of even this very fast typist attempting to take notes.
I’m skipping a lot of good material to compress this, but I do want to mention that the discussion of exoplanets by David Black (Lunar and Planetary Institute) and Ariel Anbar (Arizona State) brought the crowd up to speed on Kepler — now without fully functioning gyros but sporting a huge list of exoplanet candidates — and methods for studying biosignatures in the atmospheres of distant worlds. Jeff Kuhn’s discussion of the Colossus telescope was a fitting cap to the panel. Kuhn (Institute for Astronomy Maui) described an Earth-based instrument that could perform a census of nearby planets looking for unusual thermodynamic signals. Explaining earlier searches for Dyson spheres, Kuhn went on to discuss how civilizations use power, noting that we use half of one-tenth of one percent of the total energy our planet absorbs from the Sun. Power consumption increases, of course, as civilizations become more advanced.
The inevitable result: The thermal signals Colossus is being designed to look for. The Colossus Consortium, a private organization funded by a wealthy individual, is looking for warm exoplanets that display the heat signature of a functioning civilization. Kuhn’s slide showing Paris in the infrared, a nighttime shot taken by a satellite, drove home the point that the thermal signal we produce is significant, measurable and much larger than what we produce in light. The intention of the Colossus builders is to examine stars within 60 light years for such markers, which would be usefully free of our sociological speculations about what such a civilization might do.
Breakthrough Telescope Technologies
It’s a fascinating concept, and to see more about it, read SETI’s Colossus in these pages, or visit the Colossus site. What I like about it is that it makes no assumptions about why or how an extraterrestrial society might choose to communicate, but depends solely upon its activities on its own world. Joe Ritter, a colleague of Kuhn on Maui, went on to lead a track called “Destinations: Hidden Objects” later that day that delved into the difficulties in exoplanet detection and viewing. Ritter ran through Kepler’s woes and discussed Hubble, the James Webb Space Telescope, and the lamented Space Interferometry Mission that may live on in missions like Darwin.
And with a gorgeous slide of the famous “Pillars of Creation” region in the Eagle Nebula, he also made the point that instrument effects limit our ability to see. Check the image below to confirm Ritter’s point: The bright star at center left does not actually have a cross-like shape, reminding us that diffraction spikes can swamp signals of faint objects in even the best of telescopes. Off-axis telescope designs, which he illustrated, can help in reducing diffraction — the Solar-C experimental coronagraphic telescope on Haleakala is an example of how this can be done.
Ritter went on to discuss the uses of polarization, describing forms of spectroscopy that can use polarization to scale away randomly polarized light and leave a more workable signal. With such methods we can hope to separate the light from an exoplanet from the light of its star. The PLANETS telescope (Polarized Light from Atmospheres of Nearby Extraterrestrial Systems) has as its goal to define the atmospheric composition of exoplanets. This one is a 2-meter off-axis telescope now under development at the Institute for Astronomy of the University of Hawaii.
Joe Ritter is a great conversationalist and we enjoyed kicking these and other ideas around after hours at the hotel bar. He’s fascinated with producing thinner apertures and how thin membranes as mirrors can be manipulated by tiny actuators to retain their shape. Polarized light at particular wavelengths can be used on the right materials to create adaptive optics in which the mirror doesn’t actually have to be touched to be re-shaped. Imagine a Hubble-sized mirror (2.4 meters) weighing in at no more than one pound, or a JWST aperture weighing twelve pounds. If we can make such giant apertures, we can use them not only for telescopes but for communications or, dare I say it, as solar sails. This work is so revolutionary in its potential that I’ve asked Joe to write an article about it for Centauri Dreams to explain it in more detail. “Brute force isn’t an elegant way to produce the mirrors we need,” Joe told me. And from what I can see, the work in his lab is both elegant and paradigm-shifting.
Image: Joe Ritter, a name you’ll be seeing much more of on Centauri Dreams in relation to his work on extremely light and thin telescope apertures.
Uses of Science Fiction
Saturday was the symposium’s last full day, so it was perhaps understandable that sessions ran over in the attempt to cram everything in. All of this led to one of the most entertaining episodes of the event, Marc Millis’ talk “From Sci-Fi to Scientific Method: A Case Study with Space Drives.” Marc frequently draws on his work as head of NASA’s Breakthrough Propulsion Physics Project, but this talk is light on equations and long on imagery from science fiction films and how scenarios from such films can inspire creative thought.
An example: We constantly see spaceships in movies where the crew is walking around under what seems to be normal Earth gravity, and as far as we can tell, there is no problem with inertia even when the craft suddenly accelerates. Now if you could actually do that, Millis asks, why wouldn’t your plots take advantage of the fact? An intruder on board wouldn’t need to be handled by security forces. Instead, why not just manipulate the gravity in his location to bounce him off the walls, rendering him unconscious? And drawing on films ranging across the gamut of recent science fiction, Millis extracted scenarios and the questions they raised.
The more serious point is that even a bad science fiction movie can become a spur for thought that encourages new angles into old problems. The key is to promote creativity. Marc had to be amazingly creative himself during his presentation. When I arrived, the late-running panels in the ballroom meant that most people were still there. When Marc was almost at the end of his talk, the room suddenly filled with people, taking up the chairs and sitting on the floor. Without losing a beat, Millis simply went back to the beginning and presented the entire talk a second time. I do a lot of public speaking but I have to say this was something of a tour de force.
Image: Marc Millis amidst an impromptu reprise of his talk.
I wish I had been able to report on all the talks I attended in these pages but I didn’t have time to run through each. What a year this has been in terms of interstellar conferences. And we still have one to go, a Starship Century event to be held Monday October 21 at the Royal Astronomical Society on Piccadilly in London, with Royal Astronomer Martin Rees as a featured speaker. As I get more information about speakers at this one, I’ll pass it along, and will plan on covering the sessions via live streaming as my travel budget won’t sustain another conference this year.
It used to be that people interested in interstellar flight met in off-schedule gatherings at meetings on other subjects. The explosion of conferences this year is probably unsustainable, but it will be interesting to see what kind of schedule eventually emerges. In any case, it has been a year to remember, one that has put an exclamation point on deep space dreams capped by Voyager, our first interstellar traveler.
Time, Distance and Hybrid Engineering
One of the things I admire most about Eric Davis is his seemingly inexhaustible supply of energy. The man is constantly in motion. Davis (Institute for Advanced Studies at Austin) is active in both the Tau Zero Foundation and in Icarus Interstellar, and deeply involved in the propulsion community at numerous conferences, all in addition to his duties at IASA. He has also, for the past two years, served as a track chair at the 100 Year Starship Symposium, a role fraught with its own difficulties as it involves coordinating and reviewing submissions and dealing with presenters at the actual event. In Houston, Davis chaired the track “Factors in Time and Distance Solutions.”
At left is Eric Davis sitting across the table from me at Spindletop, the Hyatt Regency’s rooftop restaurant, which turns out to be quite good despite the fact that it rotates. Calvin Trillin came up with the applicable maxim: “I never eat in a restaurant that’s over one hundred feet off the ground and won’t stand still.” I’ve always found that to be a good rule but the Hyatt’s restaurant is an exception because of its superb seafood. In the photo, my wine glass is absurdly foreshortened — it wasn’t really that big — but the wine selection was first-rate and included the spectacular Cloudy Bay Sauvignon Blanc. Forgive me for the digression, but for ten years I was a restaurant critic for a local newspaper and still have the habit.
Bridging the Interstellar Gap
At the first track session for “Factors in Time and Distance Solutions,” Terry Kammash (University of Michigan) ran through the basics of the rocket equation to show why chemical rockets were inadequate for deep space travel. Kammash is interested in a fusion hybrid reactor whose neutron flux induces fission, a system that could eventually enable interstellar missions. It is based on Gas Dynamic Mirror (GDM) methods that surround a plasma-bearing vacuum chamber with a long, slender, current-bearing coil of wire. The plasma is trapped within magnetic fields that control the instability of the plasma. Here it’s worth mentioning that a Gas Dynamic Mirror propulsion experiment in 1998 produced plasma during a NASA test of the plasma injector system, injecting a gas into the GDM and heating it with microwaves in a method called Electronic Cyclotron Resonance Heating.
Pauli Erik Laine (University of Jyväskylä, Finland) described himself as a computer scientist rather than a rocket scientist, but the two designs he presented were based, like Kammash’s, on hybrid propulsion systems. In Laine’s case, the method is nuclear thermal propulsion, as developed through the NERVA program coupled with nuclear-electric propulsion and a gravitational slingshot maneuver for initial acceleration. Laine also discussed fission fragment rocket technologies in which heavy and light fission fragments, rather than being dissipated as heat through conventional reactor methods, are used directly for thrust. A hybrid fission fragment mission added a solar sail and used multiple staging to achieve five percent of lightspeed.
It’s always great to run into old friends at conferences like these, and I was pleased to see Charles Quarra, who had presented his ideas on what he calls a ‘light bridge to the stars’ in Dallas at Icarus Interstellar’s Starship Congress. Charles is an independent researcher and software developer now based in Panama who has written up the idea of the ‘laser starway’ on Centauri Dreams (see A Light Bridge to Nearby Stars). The work extends earlier concepts by Robert Forward and Geoffrey Landis, solving issues of laser pointing accuracy by using multiple lenses spaced between two stars to deliver the needed high energy density.
My son Miles and I took Charles down the street that evening for a drink at Guadalajara, an excellent Mexican restaurant whose margaritas were impeccable (the grilled salmon tacos were likewise outstanding). While we enjoyed the atmosphere we talked about the starway, a concept that would require continual maintenance, but once built, would become like a highway system for future missions. We go from single missions toward building a long-term infrastructure, the same issue, Charles noted, that Roman engineers faced as they spanned bridges to connect the various Roman territories and provinces. Like the starway, the bridge building was a lengthy task but ultimately it reduced travel time and kept the business of the empire in motion.
The Uses of Curiosity
But back to the “Factors in Time and Distance Solutions” track, where NASA’s Harold “Sonny” White reported on his research on hyperfast travel through the expansion and contraction of spacetime. White ran through the model provided in the 1990s by Miguel Alcubierre and explained the notion that a ring of negative vacuum energy formed around a payload would create a warp bubble within which there are no tidal forces and clock rates remain the same during the journey as they do at mission control. One of the deal-breakers for such thinking has always been the colossal energies needed to optimize the topology of the warp bubble, which until 2011 had remained as high as the equivalent in exotic matter of the mass of Jupiter.
Image: Sonny White discussing his ongoing work.
Basic to the idea is that while objects cannot move faster than the speed of light through spacetime, there is no limitation on the expansion of spacetime itself. The inflation of spacetime is indeed a feature of models of the early universe. A payload enclosed within such a bubble would thus ride a wave induced by expanding spacetime behind the bubble and contracting it in front. White’s work manipulated the shape of the bubble around the spacecraft, changing its shape and thickness, and noting that as these factors were altered, flat spacetime in the center was sacrificed but the amount of strain was reduced. The amount of energy needed is thus decreased by orders of magnitude, down to levels equivalent to the mass of one of the Voyager spacecraft by oscillating the intensity of the bubble and reducing the ‘stiffness’ of spacetime.
White’s hope is that the interferometer he has built at the Eagleworks Optical Laboratory will eventually be able to produce evidence of a tiny instance of this effect. The goal is to detect and measure the effect of this minute warp bubble on the optical path through the interferometer by measuring associated interference fringe shifts. A sister laboratory at South Dakota State University is likewise designed to make such interferometry measurements although it uses different techniques to measure the effect. “We now have separate labs working on this,” White added. “And we do have some results that indicate a potential change in the beam path length. But I want to stress that this is far from conclusive. We simply can’t say anything definitive yet. The plan going forward is to continue to investigate our software approaches, working with larger data samples to reduce vibrational noise.”
Showing photos of the current laboratory setups, White described the interferometer’s operation and then went into the concept of quantum vacuum plasma thrusters, a form of electrical propulsion that in theory could push off against the quantum vacuum. He used the analogy of a submarine propeller pushing off against water. The submarine doesn’t carry a tank of seawater; instead, it is actually immersed in its propellant. The Q-thruster attempts to push off against the virtual particles continually coming into and out of existence in the quantum vacuum.
I’ve been asked repeatedly to write about White’s work but my thought is that other than discussing his presentations at conferences like this one, the best approach would be to have him tell you about his work himself. Sonny is the kindest of men, and he readily agreed to write an article about what he is doing. I’ve asked Eric Davis to do the same thing: Both are involved in matters that go well beyond my expertise and are far better able to explain their work than I can.
White’s work in particular has become highly visible and remains controversial. In Dallas at Starship Congress, we went over to the hotel pool where cheeseburgers were on sale and enjoyed a leisurely meal and beer outside. I can still remember Sonny cringing when I told him about an email I had received saying “Now that Dr. White has solved the warp drive problem…”
“We have so far to go to find out whether this will pan out,” he told me then. “My work on all this came out of curiosity. Sometimes it’s good to pursue things just because you’re curious. It’s worth doing to see if we can learn something and we’ll see where these experiments lead.”
I’ll wrap up coverage of the 100 Year Starship Symposium tomorrow with a look at an excellent science panel moderated by Jill Tarter and a lively talk on the uses of science fiction in raising and probing scientific questions that was presented by Marc Millis. I ran out of time today before I got to Joe Ritter’s track on “Destinations,” so I’ll also be sure to get into that tomorrow. We do, after all, need to know where we’re headed.
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