Working on a book on interstellar flight in 2002, I came across a paper in the Journal of the British Interplanetary Society with a bold title: “A Programme for Interstellar Exploration.” I already knew that its author, Robert Forward, was a major figure in the world of deep space studies, an aerospace engineer and inventor with a deep knowledge of physics as well as a popular science fiction author, in whose stories many of his futuristic ideas were played out. What I didn’t know until I read the paper was that this man had proposed a step-by-step plan for reaching the stars way back in 1975 at a meeting at the U.S. House of Representatives.
These were bold years for interstellar thinking, as witness Forward’s appearance before the Subcommittee on Space Science and Applications that year. Forward developed a fifty-year plan for interstellar exploration that, in his words, ‘envisions the launch of automated interstellar probes to nearby stellar systems around the turn of the century, with manned exploration commencing 25 years later.’ He went on to discuss five possibilities for interstellar propulsion systems based on a series of projections of technology programs in nuclear fusion, particle physics, high-power lasers and thermonuclear explosives. Imagine Forward telling these political leaders that a manned starship might embark for Alpha Centauri by the year 2025.
A Home for Visionaries
It all seems a bit surreal, given what has happened to our space plans after Apollo, but Forward’s paper on these matters in JBIS is still lively reading, and so is another interstellar program put forward by Michael Michaud, then an official with the U.S. State Department. Michaud’s plan discussed the possibilities of interplanetary exploration and moved into the interstellar realm by envisioning a search for extrasolar planets (at the time, of course, we knew of none). His closely reasoned program for colonizing the Solar System would in his schedule be followed by the first star probes using fusion technologies beginning around 2010 .
Here again I turned to one of the JBIS ‘red cover’ interstellar issues, finding Michaud’s paper “Spaceflight, Colonization and Independence” in a 1977 issue. And as I began to work my way through this particular period in interstellar studies, I learned that between 1974 and 1991, the Journal of the British Interplanetary Society had published numerous red cover issues focused on interstellar matters under the editorship at various times of Anthony Martin, J. Hardy and Gerald Groves. When I mentioned the quality of this work to Geoffrey Landis during an interview at NASA Glenn, he told me that JBIS had been the home of advanced concept thinking on deep space for a long time. The red cover issues proved him right.
The problem with JBIS when I was working on my Centauri Dreams book was that, although I had access to an excellent academic library online, the JBIS Interstellar Studies issues with the red covers were, like the rest of the journal’s output, unavailable in full text form. That meant making my way to the local university library, where I quickly became familiar with the red cover issues and worked my way through Project Daedalus, not to mention the numerous studies of interstellar propulsion schemes, communications matters and speculations about alien life.
It’s good to see the British Interplanetary Society moving to make these key papers more accessible. The red cover issues, covering the full range of interstellar studies, are now available by the paper or journal issue directly from the BIS. The Interstellar Studies Index can be accessed for a look at what’s available, with the last Interstellar Studies issue being the August, 1991 journal, where I find a Greg Matloff study on precursor solar sail probes, and Robert Zubrin’s “Nuclear Salt Water Rockets: High Thrust at 10,000 Seconds ISP.” But working through the index pulls up many familiar names, including Michael Michaud’s “A Manifesto for Expansion,” many Robert Forward papers, Giovanni Vulpetti’s work on antimatter, and classic papers that have energized the field, like Matloff’s “Solar Sail Starships: The Clipper Ships of the Galaxy.” The red cover issues are a compendium of the best interstellar thinking of their era and form a key reference for anyone working on these matters today.
Building a Scholarly Infrastructure
I have stacks of printouts of these papers filled with check marks and comments here in my office. I’ve used them over the years, but paging through them I’m reminded that the red cover issues form only a part of what JBIS has published — and continues to publish — on interstellar topics. It was here that Arthur C. Clarke’s famous ‘Challenge of the Spaceship’ paper appeared back in 1946, and where Les Shepherd wrote (in 1952) the first technical paper on interstellar flight. I should also mention, in addition to numerous papers on worldships, the interstellar bibliographies produced by Eugene Mallove and Robert Forward, which built upon and extended the personal Forward bibliographies he had begun compiling while studying engineering at UCLA.
We’re talking about the infrastructure of scholarly investigation, and it’s here that interstellar studies still has to come into its own. The Mallove/Forward bibliographies were not continued because, paradoxically, they became too lengthy to maintain. Both men had ongoing research to pursue, and even as new voices emerged in the field, their subject matter of choice continued to be relatively marginalized. Interstellar specialists worked in their spare time, exchanging letters, talking at conferences, but their effort was and is a subset within the much broader aerospace domain. In that environment, full-time interstellar work is a difficult job description.
The exciting developments in astrobiology and exoplanetary astronomy may change this situation. Interstellar studies could use the kind of targeted collections found in the JBIS red cover issues, and just as significantly, could make use of a yearly interstellar bibliography focusing on the issues that define our encounter with the stars, from propulsion to communications to the philosophical questions raised by potential extraterrestrial contact. All of this is, we hope, fodder for the Tau Zero Foundation as we try to support and encourage an effort that has produced remarkable papers and is building a new infrastructure for growth.
Last week turned into a major disruption for Centauri Dreams. Major server problems that have involved new hardware and all manner of delays struck late on the night of Sunday February 27 and kept the site offline until this past weekend. Sorry for this, and thanks to those of you who kept in touch via email or via the @centauri_dreams Twitter feed. Let’s hope the situation is now under control. In any case, it’s time to get back to work, which I’ll begin with this piece on the return of NASA’s Institute for Advanced Concepts.
On my desk is a large black mug, too big for coffee despite the copious amounts of coffee I consume — I’ve got it loaded with pens, yellow markers and the like. I take special pleasure in seeing it every day because it has a bold NIAC logo on it — NASA Institute for Advanced Concepts — blue and white on a black background, and on the other side is a favorite phrase of Bob Cassanova’s: “Don’t let your preoccupation with reality stifle your imagination.” At the time he sent me the mug, Bob was the head of NIAC, and we had talked several times about issues like that, about how you fire people up to do imaginative work and push the frontiers hard.
As Centauri Dreams readers know, NIAC was de-funded in 2007, although there seemed to be a commitment on the part of those who had participated in NIAC to bring it back. I liked that optimism but didn’t see much chance of a NIAC revival because of budget realities. But now we have a new NIAC, under the capable direction of John (Jay) Falker. It’s an organization that promises to fund “early studies of visionary, long term concepts – aerospace architectures, systems, or missions (not focused technologies).” And it’s all about unusual ideas, notions at Technology Level 1 or 2 or possibly early 3, ideas that need brainstorming and seed money.
Building on the Original NIAC
I’m wishing Jay Falker well in his new role and think he’s well suited for it — before this, among a number of other things, he led the realignment of NASA’s $2 billion exploration research and technology portfolio. Will the new NIAC assume the basic charter of the old? We’ll have to wait and see. Remember that at one point, NASA was funding both the Breakthrough Propulsion Physics project and NIAC, more or less situating NIAC in the role of developing relatively near-term ideas that scaled well from known physics, while BPP looked more aggressively at the completely uncharted territory of long-term and completely revolutionary propulsion.
But the lines are never clear-cut, and those with a commitment to the idea of interstellar flight know we have to look in both directions, which is just what the Tau Zero Foundation tries to do. It’s instructive to look back at the original NIAC site, which was managed and is now preserved by the Universities Space Research Association. If you’re involved in interstellar ideas, you want to familiarize yourself with the ‘funded studies’ section, where Phase 1 and II reports are available for many concepts that could become relevant to later interstellar efforts.
Years ago, it was poking around in the NIAC archives where I first learned about Steve Howe’s work on a small, hybrid sail using anti-hydrogen and fission, a concept that seems to scale well and requires amounts of antimatter small enough to be within our reach in the forseeable future. Jim Bickford’s reports on antimatter extraction are also provocative, and you’ll also find early work by Webster Cash on the New Worlds Imager, which in its most advanced version would be theoretically capable of imaging an Earth-mass exoplanet down to the level of individual continents. Ralph McNutt’s reports on an interstellar probe are also here — this work continues at Johns Hopkins Applied Physics Laboratory under the name Innovative Interstellar Explorer, so the NIAC legacy has persisted.
Image: From a NIAC study by Robert Winglee (University of Washington) on Magnetized Beamed Plasma Propulsion (MagBeam). NIAC funded several early studies by Winglee on forms of plasma propulsion including M2P2. Credit: NIAC/NASA.
The original NIAC site is quite a resource, from the space elevator to advanced robotics, and I commend it to you. We now wait to see what kind of projects the new NIAC is interested in funding. We’re in a new world now, one in which commercial and private initiatives play an increasingly significant role in developing tomorrow’s technologies. Getting another venue for advanced proposals back into the game bodes well for space exploration, even as we try to work out the synergies that exist between government entities and efforts like Tau Zero.
Solicitations and Specifics
Be aware as well of the recently announced NASA solicitations, which can be accessed by opening the NASA Research Opportunities homepage and then linking through the menu listings “Solicitations” to “Open Solicitations.” I’ll quote directly from the relevant parts of the announcements, the first on NIAC itself:
This NRA [NASA Research Announcement] solicits multiple studies, each of which will investigate an architecture, mission, or system concept that has the potential to change the possible in aeronautics or space. NASA Innovative Advanced Concepts (NIAC) is part of the Office of Chief Technologist (OCT). Concepts proposed for NIAC Phase I studies must be innovative and visionary, technically substantiated, and very early in development (10+ years out; Technology Readiness Level 1, 2, or early 3). Focused technology maturation and incremental improvement are explicitly not of interest in this program. Finally, while NIAC encourages great leaps and accepts the accompanying risk, all proposals must be technically credible, based on sound scientific principles.
Proposals shall be submitted electronically, and all proposers shall use either NASA’s proposal data system, NSPIRES (http://nspires.nasaprs.com ) by March 29, 2011. Proposals will be due on or before May 2, 2011.
And two other solicitations, starting with this:
The Game Changing Technology Division (GCT), within NASA’s Office of the Chief Technologist (OCT) is soliciting executive summaries, white papers, and proposals for research and development (R&D) for technology that is innovative and unique and promises to enable revolutionary (game-changing) improvements to the efficiency and effectiveness of our country’s space capability. Novel (unique) capabilities are sought in any of the NASA Space Technology Grand Challenges or the NASA draft Space Technology Roadmaps. Responses may be submitted at any time while this solicitation is open. Responses will be reviewed and award decisions made throughout the year.
This announcement solicits proposals for the demonstration of space technologies that provide new system-level technological capabilities. OCT TDM is seeking to identify candidate crosscutting, system-level technologies to be demonstrated in the relevant environment such as ground, air, suborbital or orbital regimes. A key requirement in this program is that the technology under consideration must clearly be crosscutting. Crosscutting is defined as a technology with potential to benefit more than one customer, where a customer can be a NASA Mission Directorate, another government agency, academia, or the aerospace industry.
See the above site for the full solicitations, and be aware that this work aims at a higher Technology Readiness Level (TRL) than what NIAC is all about — the solicitation immediately above, for example, aims at a TRL of at least 5, with the aim of raising it to TRL 7 or higher. But all of this is interesting to watch unfold as we track the progress of technologies within NASA that may have implications for deep space missions. And it will be particularly interesting to see what kind of Phase I studies the new NIAC will implement as the Institute begins its second life.
Back when I was first thinking about writing a book on interstellar flight, my reading began with Adrian Berry’s fine study The Giant Leap: Mankind Heads for the Stars. A science writer and novelist, Berry was science correspondent for The Daily Telegraph from 1977 to 1997, and is now the paper’s Consulting Editor (Science). The Giant Leap ranged through the various propulsion options and explained the history of the interstellar idea, but I found it more inspiring still in its expression of human motivations and the urge to explore. Looking at our human history of migration and exploration, Berry liked in particular the parallel between the settlement of the Polynesian islands and our future among the stars:
It is the ‘radiative’ nature of the Polynesian voyages that provides the closest parallel to interstellar travel. It was all made possible by that forerunner of a starship, the double canoe. Imagine twin hulls about nine metres in length, covered by a single deck and a lateen sail, a craft not dissimilar to a modern catamaran… [T]hese vessels were ‘self-reproducing,’ in the sense that they were built wholly from local materials. Each time a colony settled on an island, they would cut down trees to make fresh canoes. Each of these canoes would set forth to find fresh islands, and on arriving on these, each party would eventually make fresh canoes, and so on.
It is by a method akin to this that our descendants will learn to ‘hop’ from star to star, finding suitable planets as they go, always using local materials for the construction of colonies. For migration in the future in space will be but a continuation of migration on this planet in the past, a continuing exercise of what might be called the ‘migratory imperative.’
Berry continues to explore such ideas online. The Polynesian parallel stuck with me as I began writing Centauri Dreams, and I would encounter it again in the pages of Interstellar Migration and the Human Experience (see below). But Berry’s lively book put more than a few interstellar ideas in play for me, which is why I was so pleased to learn that he recently became the Tau Zero Foundation’s largest contributor to date, donating £7000, which works out to $10,825 US. Many thanks for the support, Adrian, both financial and intellectual, that you have provided over the years.
A Bookshelf on Starflight
All of this reminds me that in what might be called the ‘hunting and gathering’ phase of writing my Centauri Dreams book, I accumulated quite a few books pertaining to interstellar flight. And because it’s part of the Tau Zero Foundation’s charter to build and maintain a list of references, it seems like a good time to post the list below. It’s very much a work in progress, one that has grown from my initial bibliography to include titles recommended to me by others (and please feel free to suggest other titles, because it’s by no means exhaustive). The division into ‘General Audience,’ ‘College Level,’ etc., is at times arbitrary but I hope it will provide at least a bit of guidance to the kind of materials available here and the range of their investigations.
Berry, Adrian (2000) The Giant Leap: Mankind Heads for the Stars. New Yorks: Tor Books.
A look at the technologies that might one day lead to the nearest stars and beyond. Discusses the options for making such journeys, along with the political and philosophical imperatives that might drive such a mission. Interesting chapters on interstellar navigation and suspended animation.
Boyce, Christopher (1979) Extraterrestrial Encounter: A Personal Perspective. Secaucus, NJ: Chartwell Books.
Speculations on the nature of alien intelligence and the possibilities for understanding and communicating with it. The odds on SETI and the possible use of Bracewell or von Neumann robotic probes for studying other planets play a role in this lively discussion.
Burrows, William E. Exploring Space: Voyages in the Solar System and Beyond. New York: Random House, 1990.
One of the best histories of the space program ever written, this book gives full weight to automated probes rather than manned flight, and speculates on the technologies that will take us outside the Solar System. Burrows’ look at the politics behind programs like the Space Shuttle resonates today.
Calder, Nigel (1978) Spaceships of the Mind. New York: Viking Press.
Speculations on space technologies including many interstellar concepts. Numerous useful though dated illustrations. The driving factors pushing space colonization are carefully examined.
Forward, Robert L (1995) Indistinguishable from Magic. New York: Baen Books.
Perhaps the greatest interstellar theorist of them all, Robert Forward offered mission concepts galore in the course of his career, many of them entertainingly discussed in this collection of essays. The author’s wry humor often shows through in discussions that range from wormholes to antimatter engines.
Friedman, Louis (1988) Starsailing: Solar Sails and Interstellar Travel. New York: John Wiley & Sons.
Friedman’s background working at the Jet Propulsion Laboratory on a once-considered solar sail mission to Halley’s Comet allows him to tap deep resources in explaining how solar sails will one day open up the Solar System, with potential for interstellar flight via particle or laser beam.
Kaku, Michio (2008) Physics of the Impossible: A Scientific Exploration into the World of Phasers, Force Fields, Teleportation, and Time Travel. New York: Doubleday.
Kaku discusses three levels of ‘impossibility,’ ranging from things we may one day puzzle out to technologies that would strike us as indistinguishable from magic, to use Arthur Clarke’s fine phrase. This wide-ranging study includes a look at interstellar technologies now under active study.
Krauss, Lawrence (1995) The Physics of Star Trek. New York: Basic Books.
A theoretical physicist offers thoughts on the scientific wonders of the popular TV series, discussing such issues as teleportation, time travel, warp drive and black holes. Excellent at untangling the futuristic but possible from the hugely improbable, based on known physics.
Macvey, John W. (1977, 1991) Interstellar Travel: Past, Present and Future. New York: Stein and Day.
Revised in 1991, this book examines interstellar travel technologies ranging from space arks to wormholes, with a long discussion of the nature of extraterrestrial life and how it might communicate with humans. Wide-ranging and easy to read, this is a good choice for young readers.
Myrabo, Leik and Dean Ing (1985) The Future of Flight. New York: Baen Books.
Starship drives are only one of the topics covered by this survey of future flight technologies, but the interstellar chapter is strong, surveying concepts from the Bussard ramjet to the laser-driven lightsail and antimatter engines. A good backgrounder for those wanting a quick survey of these ideas.
Nicholson, Iain (1978) The Road to the Stars. New York: William Morrow & Co.
A well-illustrated and lively survey of future space technologies, with a useful discussion of SETI and the possibilities of communicating with extraterrestrial intelligence. The major ideas for upgrading today’s engines are presented, beginning with ion drives and carrying forward to the Bussard ramjet.
Sagan, Carl (1980) Cosmos. New York: Random House.
Carl Sagan’s classic offers some of the most captivating illustrations ever made available in a space book. While the book, like the TV series it parallels, offers perspective on the entire human experience of the heavens, it places the possibilities of interstellar flight in a readable, powerful context.
Wright, Jerome L. (1992) Space Sailing. New York: Taylor & Francis.
A history of the solar sail concept, one that uses momentum from the Sun’s own light to drive a space vehicle, without the need to carry heavy fuel. Well illustrated, this book examines all the ways solar sails may change our future in space, both in the near term and the far.
Adelman, Saul J. and Benjamin Adelman (1981). Bound for the Stars: Space Travel in our Solar System and Beyond. Inglewood Cliffs, NJ: Prentice-Hall.
The exploration of space from travel in the nearby Solar System to interstellar missions. The latter chapters discuss interstellar propulsion, navigation, the search for extrasolar planets and the first starship. Useful discussions as well about a plausible program for long-term interstellar planning.
Andreadis, Athena (1999) To Seek Out New Life: The Biology of Star Trek. New York: Three Rivers Press. A professional biologist goes to work on life sciences as depicted in Star Trek, with thoughts on everything from telepathy and the genetic code to the cultural sameness of the societies the Enterprise’s crew encounters. Entertaining and instructive.
Clarke, Arthur C., ed. (1990) Project Solar Sail. New York: Roc.
Useful essays from leading theorists examine the role of solar sails in future space missions, with attention to missions in the Solar System and beyond. The essays are interleaved with short fiction and even poetry that explores plausible scenarios for putting sails to work.
Dole, Stephen H. and Isaac Asimov (1964) Planets for Man. New York: Random House.
This is the popular version of a RAND Corporation study originally performed by Dole. The later version includes the thoughts of Isaac Asimov, and examines the factors necessary for planets to be habitable for humans, and our chances of finding them. Although dated, this book still offers useful information about the concept of a habitable zone and the factors that will one day make particular planets useful destinations for our probes.
Dyson, George (2002) Project Orion: The True Story of the Atomic Spaceship. New York: Henry Holt and Co.
Freeman Dyson’s son tackles the great attempt to wed nuclear technology to deep space missions, Project Orion. Told with flair and access not only to key documents but the recollections of the major players, this history shows how one team of experts viewed journeys to the outer Solar System and beyond before the realities of the Test Ban Treaty put the concept beyond reach.
Forward, Robert L. and Joel Davis (1988) Mirror Matter: Pioneering Antimatter Physics. New York: John Wiley & Sons.
Interstellar theorist Robert Forward offers a thorough background to the history of antimatter research. Propulsion concepts that could drive our first starships are examined, while the methods for creating and storing antimatter and using it here on Earth receive solid scrutiny. The chapter on antimatter in science fiction is particularly energetic.
Gilster, Paul (2004) Centauri Dreams: Imagining and Planning Interstellar Exploration. New York: Copernicus Books.
Surveys methods for moving an interstellar probe to speeds that could reach nearby stars in a single human lifetime. These range from fusion to antimatter, beamed lightsails, magnetic sails, Bussard ramjets and other concepts. Also covers interstellar navigation and exoplanet detection.
Kaku, Michio (1995) Hyperspace: A Scientific Odyssey Through Parallel Universes, Time Warps and the Tenth Dimension. Oxford University Press.
Understanding the possibilities of interstellar flight demands a look at the things that may warp space and time, including wormholes that could offer fast transit without exceeding the speed of light. Michio Kaku explains the options with a minimum of jargon and clear, readable prose.
Mallove, Eugene F., and Gregory L. Matloff (1989) The Starflight Handbook: A Pioneer’s Guide to Interstellar Travel. New York: John Wiley.& Sons.
A classic of interstellar studies, Matloff and Mallove’s book provides the necessary theory to understand the various propulsion methods proposed to reach the stars. All major concepts are considered by two authors who have been involved in interstellar concepts for decades.
Matloff, Gregory, Les Johnson and C. Bangs (2007) Living Off the Land in Space: Green Roads to the Cosmos. New York: John Wiley & Sons.
Space travel as we do it today requires large amounts of fuel that take up a major part of the rockets we launch. How we can learn to use resources in space itself may determine how soon we push into the outer Solar System and beyond. The science behind space tethers, solar sails and other techniques for in-System voyaging are here explored, along with speculations about even more audacious concepts that could take us to the stars.
Matloff, Gregory, Les Johnson and Giovanni Vulpetti (2010) Solar Sails: A Novel Approach to Interplanetary Travel. Berlin: Springer. A comprehensive survey of solar sail concepts ranging from near-term designs like the Solar Polar Imager to interstellar possibilities enabled by laser-driven lightsails, this book summarizes our sail knowledge at the beginning of the solar sail era, with numerous thoughts on sail design, construction, deployment and trajectories.
Savage, Marshall T. (1994) The Millennial Project: Colonizing the Galaxy in Eight Easy Steps. New York: Little, Brown & Co.
An optimistic look at how mankind can spread into the cosmos, offering a program to transfer a large proportion of the world’s population into venues off-planet. Step by step improvements lead to terraforming Mars, using the resources of the outer system, and moving to the nearby stars.
Strong, James (1965) Flight to the Stars. New York: Hart Publishing Company.
An early classic of interstellar studies, Strong’s book offers a rationale for the human expansion to the stars, while considering a variety of propulsion concepts to get the job done. While dated in specifics, the scenarios considered here paint possible futures for a star-faring race with vigor and enthusiasm.
Thorne, Kip S. (1994) Black Holes and Time Warps: Einstein’s Outrageous Legacy. New York: W.W. Norton & Co.
Thorne is a major player in the theory of wormholes, and thus the kind of distortions of spacetime that may one day make it possible to travel vast distances quickly without ever exceeding the speed of light. This book places his theories into the Einsteinian context in readable if challenging fashion.
Zubrin, Robert (1999) Entering Space: Creating a Spacefaring Civilization. New York: Tarcher/Putnam, 1999.
The case for becoming a spacefaring civilization is made with enthusiasm and panache. The action ranges from terraforming nearby Mars to exploiting the resources of the outer planets, with solid chapters on interstellar propulsion and contact with extraterrestrial civilizations.
- Graduate/Professional Level
Czysz, Paul and Claudio Bruno (2009) Future Spacecraft Propulsion Systems: Enabling Technologies for Space Exploration. Berlin: Springer.
Space propulsion systems from near-Earth to the outer Solar System and beyond. Focus on applied engineering working within the known principles of physics, with emphasis on fusion rocket designs and the extension of today’s technologies to missions into deep space.
Doody, Dave (2009) Deep Space Craft: An Overview of Interplanetary Flight. Berlin: Springer.
Descriptions of interplanetary spacecraft with detailed looks at their instrumentation and the Earth-based operations needed to acquire and process their incoming data. Flight operations and the interactions between a mission’s science team and the light team are examined, with detailed appendices on the range of instruments that have so far flown, and those likely to be aboard spacecraft in the future.
Finney, Ben R. and Eric M. Jones (1985) Interstellar Migration and the Human Experience. Berkeley: University of California Press.
This is a compilation of papers from the Conference on Interstellar Migration held at Los Alamos in May of 1983, which examined not only the scientific possibilities, but also the social, ethical and even legal ramifications of our move into the cosmos. Its look at how humanity has coped with past challenges, such as the settlement of the Pacific islands, places interstellar migration in context.
Kondo,Yoji, ed. (2003) Interstellar Travel and Multi-Generational Space Ships. Apogee Books Space Series 34. Collector’s Guide Publishing Inc (June 1, 2003).
Papers from a symposium of the American Association for the Advancement of Science in 2002, exploring propulsion concepts and the solutions needed for flight to the stars. The book also addresses the cultural and psychological issues related to long-term voyaging and ponders ‘generation ships,’ in which crew members spend their entire lives on voyages several centuries in duration.
Maccone, Claudio (2009) Deep Space Flight and Communications: Exploiting the Sun as a Gravitational Lens. Berlin: Springer.
Maccone has long been the champion of a mission to the Sun’s gravitational lens at 550 AU and beyond. Here he lays out the results of his two decades of study of the concept, discussing possible probe designs, the best targets for investigation, and the underlying principles of lensing. Section 2 examines the challenge of communicating between an interstellar spacecraft and the Earth, focusing on the opportunities found in the Karhunen-Loève Transform (KLT) for optimal telecommunications.
Matloff, Gregory L. (2005) Deep Space Probes: To the Outer Solar System and Beyond. Berlin: Springer/Praxis Books.
Recently revised, Matloff’s look at deep space technologies offers abundant references in its examination of current theories of interstellar propulsion, including nanotechnology and ramscoops that draw their fuel from hydrogen between the stars. Also included are speculations on astrobiology and the development of self-reproducing von Neumann probes that could saturate the galaxy.
Mauldin, John H. (1992) Prospects for Interstellar Travel. American Astronautical Society Science and Technology Series, Vol. 80. San Diego, CA: Univelt.
A thorough study of interstellar flight possibilities that covers, in addition to the relevant propulsion concepts, every aspect of starship design, including the navigation problem and the difficulties posed by lengthy voyages with human crews. The overall engineering of space probes designed for such missions is discussed at length, with abundant references for follow-up reading.
McInnes, Colin R. (1999) Solar Sailing: Technology, Dynamics and Mission Applications. Chichester, UK: Praxis Publishing.
The most exhaustive study of solar sail technology available, offering a rich list of references for specialists. Applications for near-term missions are considered in detail, with the relevant equations for understanding the forces at work. A thorough examination of sail materials and design explains where we are now and how solar sails may change the economics of propulsion. Beamed lightsails for interstellar missions.
Millis, Marc and Eric Davis, eds. (2009). Frontiers of Propulsion Science. Reston, VA: AIAA.
A compilation of essays from specialists about the prospects for breakthroughs that could revolutionize spaceflight and enable interstellar flight. Five major sections are included in the book: Understanding the Problem lays the groundwork for the technical details to follow; Propulsion Without Rockets discusses space drives and gravity control, both in general terms and with specific examples; Faster-Than-Light Travel starts with a review of the known relativistic limits, followed by the faster-than-light implications from both general relativity and quantum physics; Energy Considerations deals with spacecraft power systems and summarizes the limits of technology based on accrued science; and, From This Point Forward offers suggestions for how to manage and conduct research on such visionary topics.
The Exoplanetology site is developing a tool for those in need of quick exoplanet information. The Exoplanet Seeker is an interface that will make it easy to query various exoplanet databases, including the Extrasolar Planet Encyclopedia, NASA’s PlanetQuest New Worlds Atlas, the Exoplanet.org site and other sources like the Wikipedia and SIMBAD. Each of these sites has its own strengths, from light curves to graphical charts, so bringing them together will be helpful once early bugs in the interface (producing frequent failed queries) are resolved.
From tools on the Net to tools in space, it’s always interesting to speculate on what’s in the pipeline. Maybe ‘pipeline’ is too strong a word, though, because tools like the Transiting Exoplanet Survey Satellite (TESS) have to be approved by NASA, which is willing to consider an earlier version of the instrument it rejected but can offer no promise of success. Nonetheless, the results from CoRoT and the early detections of Kepler (not to mention the possibilities of WISE in finding nearby brown dwarfs) keep space instrumentation in sharp focus.
We’ve looked at TESS before, noting that its six wide-angle lenses would be put to use flagging stars with planets, building a list that the James Webb Space Telescope (to be launched in 2014) would then study in greater detail. What’s interesting about TESS, as this short article in Popular Science points out, is that it would scan a chunk of sky some 400 times larger than Kepler. That involves 2.5 million of the closest stars, a search that should return an abundance of interesting worlds to study.
Image credit: MIT.
The thinking of the TESS team, according to this MIT news release, is that between 1600 and 2700 planets might be found in the first two years of observations, including between 100 and 300 small, rocky worlds. The light curves produced by the planetary transits TESS observes would then be passed along to observatories on the ground and slated for spectroscopic analysis by the Webb instrument. The latter could potentially reveal details about planetary atmospheres and their constituents. Expect a new TESS proposal to be submitted this year to follow up an earlier initial feasibility study.
Meanwhile, we continue to watch the development of the Webb telescope with great interest. Mark Clampin (NASA GSFC), discusses the possibilities for planetary spectroscopy in an instrument originally designed to search for the earliest galaxies. JWST will be able to extract a lot of information from a planetary transit:
“By comparing the two spectra for the star (in and out of transit), we can extract the planet’s spectrum and learn about the planet’s atmosphere. We have to collect a lot of infrared light — a billion or more photons — for each spectral element to isolate features. Webb is perfect for this kind of study.”
TESS could be quite useful in feeding targets to JWST, but the latter will also be doing planet-hunting of its own using coronagraphic techniques that block the light of stars so planets around them are more readily visible. Clampin continues:
“Webb will show us what the ‘exoplanet zoo’ looks like. This telescope will be very good at observing and taking spectra of gas giant planets, and we can take some spectral data on smaller planets, too, about Neptune-sized. Our telescope will also zoom in to study newly discovered super Earths — planets bigger than Earth but smaller than Neptune.”
Exciting times ahead as we contemplate our next steps in space-based observation, especially the deployment of JWST’s 25 m2 collecting area. Will JWST be able to tell us whether life exists on distant terrestrial worlds? Probably not, though Clampin isn’t above hedging his bets:
“A true Earth twin would be too small to emit enough infrared light from its atmosphere for Webb to pick up. Still, every time scientists make statements like that, someone proves them wrong. Transit science is changing so fast, it’s hard to say exactly what wonders Webb’s hunt will turn up.”
A recent NASA article on JWST is here.
Caleb Scharf is director of the Columbia Astrobiology Center and author of a new book I intended to mention in Saturday’s Notes & Queries section before running out of time. I want to be sure to insert it now, because if you’re getting serious about the study of astrobiology, you’ll want to know about this title. Extrasolar Planets and Astrobiology (University Science Books, 2008) is designed for university courses on the subject, with extensive background not only in the relevant physics and mathematics, but also in chemistry, biology and geophysics, studies the multi-faceted world of astrobiology melds into a complex whole.
The book is actually based on the upper-level course Scharf has been teaching at Columbia. The author tells me in an e-mail that his intent is specifically to reach students serious about moving into the discipline: “The aim is to provide the basis for students to gain a real understanding of how to actually do research on exoplanets, as well as some of the broader science encompassed by astrobiology.” Making the point are the exercises designed for each chapter to draw newcomers into research and provide examples for calculation. I also want to mention the book’s online component, where news items are cross-referenced with the book.
And I like what planet-hunter Geoff Marcy has to say in his foreword, especially in its hint of long-term interstellar travel:
For the future, NASA and the Jet Propulsion Laboratory have developed the Space Interferometry Mission that will use the interference of light waves gathered by a spaceborne pair of telescopes to detect earth-like planets, and measure their masses, around nearby stars. Just over the horizon are plans for a spaceborne telescope that blocks the glare of nearby stars, allowing us to take images of Earth-like planets and to determine their chemical composition from their spectra. Any worlds having oxygen atmospheres and surface oceans will smell fishy from 40 light years. This census of habitable earths will fill GoogleGalaxy with ports-of-call for our grandchildren who will send robotic probes and later themselves, at least those with extreme daring and patience. The urge to explore these new worlds comes from our anthropological roots at Olduvai Gorge two million years ago. What sets us apart from the stones and the stars is our insatiable desire to understand our kinship with both.
Nicely put, and I especially like that GoogleGalaxy bit, the updated and searchable version of the Encyclopedia Galactica. Scharf looks hard at how we study planet and star formation, how we observe exoplanets and undertake chemical and biological modeling. I’m glad to see that he does not claim definitive status for the book in a field as malleable as this, but treats astrobiology as an ’emerging interdiscipline’ — exactly the right phrase — while his audience is “…the student or researcher in astronomy or physics, or possibly someone from the geophysical, chemical, or biological sciences, looking for a deeper understanding of the ‘astro’ in astrobiology.” Those looking for an astrobiology career will want Extrasolar Planets and Astrobiology on their shelves.
And thanks to all who have been asking about our Frontiers of Propulsion Science book, which is now turning up on the AIAA site. Although we had hoped for publication by the end of the year, it’s now looking like February is the likely target. Edited by Marc Millis and Eric Davis, Frontiers of Propulsion Science is a graduate/professional-level text and a first-ever compilation, as AIAA points out on the site, of the emerging science behind breakthrough concepts like warp drive and faster than light travel. In these areas we’re obviously still very early in the game:
This is a nascent field where a variety of concepts and issues are being explored in the scientific literature, beginning in about the early 1990s. The collective status is still in step 1 and 2 of the scientific method, with initial observations being made and initial hypotheses being formulated, but a small number of approaches are already at step 4, with experiments underway. This emerging science, combined with the realization that rockets are fundamentally inadequate for interstellar exploration, led NASA to support the Breakthrough Propulsion Physics Project from 1996 through 2002.
The hope is that a book like this can energize research so that more studies are performed, more papers written, and new compilations can begin to emerge on a regular basis. Our universities need the reference tools to bring structure to the courses that grow out of these studies, and we hope Frontiers of Propulsion Science is a step in that direction.