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Tau Zero Foundation

by Marc G. Millis

Marc Millis, former head of NASA’s Breakthrough Propulsion Physics program and founding architect of the Tau Zero Foundation, now gives us a look at the Foundation’s current status and his thoughts on where it’s going.

To those who have been waiting for the Tau Zero Foundation to begin in earnest, your patience is greatly appreciated. We are definitely making progress and this article describes that status.

Sneak preview

For the readers of Centauri Dreams, the URL at the end of this article takes you to a sneak preview of our public website. Although the site is far from done (many corrections and additions still needed) enough content is there to give you an idea of what we’re delivering. Donations can now be accepted via the “support us” page (hint, hint). Yes, even modest donations speed up progress. We are, after all, still an all-volunteer effort, setting this up in addition to our day-jobs.

Stages of Implementation

Initially a network of volunteers, the Tau Zero Foundation’s practitioners will share their progress and insights with each other and on the public website. These practitioners have been selected to provide a complementary blend of disciplines (researchers, educators, journalists) and for their ability to deal with visionary subjects in a productively rigorous manner. Through these collaborations and by taking advantage of existing venues, occasional projects will be undertaken (books, documentaries, workshops). Once sufficient funding is secured, cycles of research will be supported, with a suite of tasks selected to advance a reasonable breadth of approaches. Within these, scholarships will also be offered to help promising students.

And where does Tau Zero stand in achieving its aims? Here are the envisioned stages of implementation. Right now, we are completing the Basics and moving onto our Debut, plus we’ve already started on some zero-cost opportunistic projects.

The Basics

  • Legal details and defining documents
  • First tier practitioners signed up (over 3 dozen)
  • Web presence constructed

Debut and Thereafter (assumes at least modest donations)

  • Continually add/refine Web content from specialty practitioner contributions
  • Devise means to identify and add new practitioners
  • Shift from “donations” to “membership” contributions
  • Tackle opportunistic projects (books, student design projects, documentaries, awards)

Scaling Up (after substantial donations)

  • Strategically select public education projects/products
  • Grant awards to those who have demonstrated the appropriate blend of vision and rigor in their work.
  • Complete formal process for inviting and supporting research tasks.

Fully Functional (requires annual donations beyond $6 million)

  • Inviting, selecting and supporting research
  • Regular conferences to review progress and prompt next proposals

Ultimate Embodiment

  • Invitational sabbatical research institute
  • Supporting actual interstellar missions

Tau Zero Scope

Tau Zero Foundation logo

Based on the news about the forthcoming book, Frontiers of Propulsion Science (an example of an opportunistic project), some have asked if Tau Zero is focusing only on space drives and warp drives. No, Tau Zero covers the full span of the seemingly simple solar sails through the seeming impossible faster-than-light travel, and will even deal with sociologic implications of interstellar adventures. The Frontiers book represents the work of only some of our practitioners. Whereas prior interstellar flight publications dealt with technology, there was a void of reliable information about interstellar flight science, things like gravity control propulsion and faster-than-light travel.

Recently, other Foundation practitioners published the book Living Off the Land in Space, which deals with nearer-term technology rather than physics breakthroughs. A large portion of the Foundation’s practitioners are enthusiastic about nearer-term possibilities. Right now, it is premature to go into any of their contributions because I don’t want to make promises for things that we might not get the support to finish.

The sociological aspects are also important since they are the source of motivation (for humanity to survive and thrive) and affect how such work can be pursued in contemporary societal contexts. So far, the Foundation has barely begun to address such vital issues explicitly.


This brings me to another area for clarification; in part a legal obligation to address. The Foundation is NOT in any way affiliated with, or supported by, NASA. For me, NASA is my day-job and has occasionally allowed me to work the technical details of revolutionary spaceflight, but there is so much more that needs to be done than can fit within that day-job. It’s taken some time to work with the NASA lawyers to make sure that I what I do on Tau Zero does not conflict with my day-job and does not violate Federal regulations (you might be surprised about some of those regulations. Sigh).

For example, many of my contributions to the Frontiers of Propulsion Science book were done on NASA time (with clearance from legal & management), although the publisher is the American Institute for Aeronautics and Astronautics (AIAA). AIAA is a professional society that provides a venue through which authors of multiple affiliations and nationalities could jointly contribute as well as providing the financing and distribution of the book to pertinent audiences. Although modest royalties will go to the non-government authors (government employees cannot accept honoraria for work done in their day-jobs), my NASA involvement in this book precludes any royalties going to the Foundation. The public companion book, however, will be handled differently.

I am also compelled to clarify the distinction from my NASA day-job because some of you have expressed the opinion that the government should support the things we do. Alas, that is not possible and the reasons are complex. This is where those sociological implications come in, and why my colleagues and I are seeking citizen and philanthropic support. As one example, when there was government funding, much of it was directed, via congressional earmarks, to boost weak regions rather than being sent to the best professionals.

Also, many of the Foundation’s activities are not allowed in US Government service. Unlike Federal agencies, this Foundation can: (1) Accept volunteer work (2) Accept donations directed for a specific purpose, (3) Create promotional materials as part of educational outreach, (4) Use the allure of science fiction as a thought-provoking tool, and (5) Earn revenue from products.

It’s not just an issue of money. It will not take that much money to make a significant difference. It is about adapting to current conditions and finding the best people. The kind of progress that we deliver is not the sort of thing that can just be assigned. It is a matter of finding today’s pioneers, wherever they may work, and bringing them together to amplify each other’s progress.

Our Niche

There are already well-run space organizations and this Foundation will not attempt to duplicate their fine efforts. Instead, this Foundation will rely on existing organizations whenever possible, channeling support to pioneers who can make the most out of existing research and publication venues.

For example, the Journal of the British Interplanetary Society is already a well-established peer-reviewed journal through which to expose and critique emerging concepts of interstellar flight. Numerous scientific and engineering journals exist for vetting more specific details. Advocacy organizations, such as The Planetary Society and the National Space Society already exist to urge our political leaders to become better educated and more supportive of space endeavors. The X-Prize organization, which is funded through donations, is doing a fantastic job of provoking near-Earth entrepreneurial space adventures. Already their first prize helped launch Virgin Galactic with Burt Rutan’s winning spacecraft. Their next prize is aimed at getting affordable robots to the Moon! The SETI Institute’s Project Phoenix, another privately funded effort, is focused on listening for evidence of extraterrestrial intelligence. And then there is academia, which teaches students how to become engineers and scientists. Lastly, there are NASA, the European Space Agency, and other government space organization that follow whatever charter their political leaders can agree on for them. Yes, that was a loaded comment, and I’ll drop it there.

What is missing from all this is an organization that looks beyond for the revolutionary advances that would change everything. And with that, providing the inspirations and reliable information from which students can become tomorrow’s pioneers. Being at the edge of knowledge can be risky. By accepting the challenge of the seemingly impossible goal of practical interstellar flight, we could very well discover what routine research overlooks, jumping significantly ahead. For example, science fiction will be deliberately used for its “what-if” and inspirational values, technical investigations will cover what others aren’t, and the provocative social implications will be explored, from the immediate effects of pursuing such a long-range endeavor, to pondering the implications of interstellar excursions, and of contacting extraterrestrial intelligence.

Since that kind of visionary work is difficult to support within established organizations, philanthropic support is sought. Consider for example SETI, the Search for Extraterrestrial Intelligence. It was once a government sponsored project that got nixed for being too visionary. With the support of wealthy philanthropists, it resumed its listening. The idea of going beyond that – beyond just listening to figuring out how to get out there – is even more daunting, but a niche that must be filled. The sooner we start working on those prospects, the better we will prepare humanity for the future.

Anticipated Roadblocks

I thought I’d share with you the difficulties we are likely to encounter as we get this Foundation running. It is my hope that, by providing you these insights, you can better grasp the real challenges we face. The goal is to find a way where our audience, you, can help us help you.

As we are finding out, trying to fit in this endeavor in addition to our day-jobs is proving more difficult that anticipated. That is why it is taking so long to get Tau Zero fully on line. Hopefully, as donations come in, we can offload some of the more routine tasks and perhaps even offer honoraria to help our practitioners accelerate their progress.

Obviously securing funding will be an issue. Finally we are now able to accept donations. Related to that is the condition that this Foundation cannot seek government funding so long as I am employed by the government or serving as the Foundation’s president. That does not, however, bar any of our practitioners from seeking government funding directly through their own affiliations, should government funding become available from time to time.

We are also likely to be overwhelmed with more requests that we can respond to. We do indeed want to hear what you think so that we can better serve you, but there are some inputs that are more helpful than others. For example, if you have encountered a book, article, or website that you have found particularly useful, please tell us about it. If there is something that you very much want us to teach on the site, please tell us about that too.

But that said, we’d prefer that you not send in your own work unless it has already been reviewed and published by another peer-reviewed source. If prior experiences are any indicator, I suspect that many enthusiasts will want us to evaluate their ideas. Because of the time-consuming difficulty of providing such reviews and because the results are seldom encouraging, we cannot provide such services. If I had a staff on hand to provide such evaluations, the cost of making the kind of thorough review necessary (given the sheer number of proposals) could reach $5000 per evaluation. Given the constraints not only on funding but the time of working scientists, we can only accept concepts that have been examined by a jury of professionals with solid credentials in the field.

I also know that many of you want us to provide a moderated forum where you can discuss your ideas with others. To a degree, we provide this function with the comment sections following the Centauri Dreams’ articles, although Paul Gilster believes that weblog software is not optimized for this kind of discussion. I was recently informed that one of our practitioners has volunteered to experiment with methods to provide such online discussions. Given the volume of anticipated inputs and the difficulty of moderating such discussions – to let in provocative ideas while filtering out cranks – this service may take a while to debug. From my own experiences of trying to do this in the past, this is a daunting challenge. We may not succeed.

What we can do, and will do, is to provide guidance for how enthusiasts can advance their own work using all the mechanisms that already exist. This includes explaining – via the website and our publications – what has been already done, explaining the foundations of knowledge as they stand today, guiding you to what to study in school, and identifying suitable publishers to whom you can submit your work.


For humanity to reach other habitable worlds or be prepared to escape or prevent Earth disasters, much work is needed. While existing space organizations take the next obvious steps and entrepreneurial adventures bring the thrill of spaceflight to the people, this Tau Zero Foundation reaches beyond for the advances that others are not even looking for – advances that would revolutionize spaceflight. This is the realm of pioneers, risk-takers, and breaking with established norms. You can support this quest through your donations, by identifying the best-quality works to share, and by telling us what you need to know to make progress of your own. We will do what we can to share that information via publications and websites and to actually make the technical progress to take humanity to the stars – ad astra incrementis.

Sneak Preview of Tau Zero Website

Comments on this entry are closed.

  • kurt9 July 8, 2008, 13:44

    The Zero Tau organizers may want to contact and work with the Earthtech people (www.earthtech.org). Although they have some speculative ideas in physics that are definitely not accepted by the mainstream scientific community, they are serious, level-headed experimenters that do not allow any wishful thinking to interfere with their experimental efforts. They have debunked many a cold-fusion claim while maintaining an open mind to the possibility of alternative physics theories. I believe the Earthtech guys are gearing up to replicate the Tajmar experiments later this year.

  • Administrator July 8, 2008, 13:51

    Thanks, kurt9 — Eric Davis at Earthtech is already one of our practitioners.

  • Dennis July 8, 2008, 17:04

    Great! I was waiting for Tau Zero to go public for a long time. I hope I would be able to contribute something to their goals

  • Darnell Clayton July 8, 2008, 19:54

    Out of curiosity, why did you pick the Tau Zero name for the foundation? Just wondering. :-)

  • Darnell Clayton July 8, 2008, 19:59

    Never mind. The site explained it on the “history” link. I’ll put my hand down now. ;-)

  • Ronald July 9, 2008, 4:58

    now that kurt9 mentions it: didn’t you promise us some more to come soon on the Tajmar experiments recently?

    Not to be pushy, but out of sheer curiosity and interest. This is one of the few ‘advanced technologies’ that fascinates me.

  • BRS July 9, 2008, 13:00

    It’s not as sexy as warp drive, nor as grassroots-appealing as solar sails, but Franklin Chang-Diaz’s VASIMR work probably has the most relevance to interstellar technology of any advanced-stage developmental project. If I understand correctly, it provides the initial field-control framework that could eventually be scaled into fusion rocketry.

  • John Hunt July 9, 2008, 13:19


    I had previously taken issue with what appeared to be TZF’s emphasis on:
    – the “impossibility” of interstellar travel,
    – a slow, incremental approach,
    – soft motivators (e.g. spinoffs and educational and humanity inspiration),
    – and propulsion based upon uncertain physics.
    I still am concerned about these things but your post and the TZF website goes a long way to show that the door is not closed to exploring the possibility of a near-term interstellar mission. I think I presumed too negatively towards TZF for which I apologize.

    However, I still wish that the “Getting There” page could be adjusted. The “Now” missions are described as:
    – Tens of millennia to get to the nearest stars,
    – 100% Feasible to launch,
    – 0% Feasible to still be operating by the time it reaches another star, and
    – half-million years to reach a possibly habitable planets

    The solar wind travels at about 1,000,000 km/hr. A craft traveling at that speed would take about 4,730 years to reach Alpha Centauri. This is less than “tens of millenia”. At most the Innovative Interstellar Explorer (IIE) would take 42,000 years. I would like to suggest that that line be changed to “5,000 to 40,000 years”

    IF a superconducting magnetic field could be maintained for this duration then cosmic radiation could be kept below 0.5 rem/yr thereby protecting the equipment. Is it really certain that the equipment would have 0% feasibility of working?

    Further, “habitable” does not require liquid water. We will inhabit Mars one day. There are 23 stars within 12.5 light-years of Earth. Reaching a habitable planet could then take between 5,000 and 500,000 years. The half-million years seems to me to be unnecessarily conservative. Perhaps “Tens to hundreds of thousands of years” would be better.

  • James M. Essig July 9, 2008, 21:19

    Hi Folks;

    The Tajmar experiments are greatly intriguing to say the least.

    I can expect that as we develop novel materials and even perhaps stable super heavy elements yet to be created or discovered, we will uncover new physical phenomenon which could benefit the cause of manned interstellar space travel.

    Perhaps programs like Duke University’s general efforts to produce meta-materials with novel electromagnetic properties can also be of help here.

    Regarding the Tajmar experiments, the superconductor plates rotating at about 6,000 RPM seems to have effected slight gravity modification. I wonder what 60,000 RPM could do. Perhaps the effect will prove to scale in a faster than linear relation, especially above a certain angular rotational velocity.

    I would like to see what effects superconducting rotors made from antimatter would do.

    Perhaps some sort of molten or exotic antimatter superconductors, or for that matter, normal matter superconductors as such could effect electro-gravatic phenomenon. Just imagine all of the fluid flow flux geometries that could be tested with such liquid superconductors. In theory, any shape of flow path or conduit shape could be tested that has its counterpart in plumbing or steam fittings.



  • John Hunt July 10, 2008, 2:34

    BRS points out that VASIMR is an advanced-stage development technology with interstellar relevance.

    VASIMR has been listed with these caracteristics:
    Thrust (N) = 40 – 1,200
    Effecitve m/s = 10,000 – 300,000

    By my calculations, at the high end this would mean a travel time to Alpha Centauri of 4,387 years. This might be in the realm of still-functioning equipment.

  • BRS July 10, 2008, 12:28

    The applicability of VASIMR is its potential upscaling into fusion energies, which would yield speeds much higher than those attainable with just accelerated plasma. However, to get there requires large improvements in power, field control, and shielding – all possible without any new physics, and far more enabling if realized than sails. This is precisely the sort of R&D work the Tau Zero Foundation exists to catalyze.

  • Marc Millis July 10, 2008, 13:10


    The ‘getting there’ page is still in pretty rough shape. Moving from general introductory material for new audiences into the specifics suitable for engineers is, well, damn hard. That page and its daughter pages will evolve a lot over time.

    Regarding any of the competing methods, be they Solar Wind/Mag Sails, VASIMIR, or whatever, it is important to have ‘non-advocate’ assessments of what these can really do, and how much work it will take to get any of them fully functional. That will take time, and a lot of ‘honest brokers’ who are dedicated to how best to proceed rather then on promoting their pet solutions. Usually the proponents will paint a rosier picture and gloss over their Achilles’ heels.

    Furthermore, what is ‘best’ depends on objectives, and with interstellar ambitions these span wide variations. The functionality of a ‘colony ship’ is considerably different than quick-probes (don’t forget reliability and the amount of power required to return signals to Earth), and both of these are different than little missions just to learn how to do a mission.

    Also, one needs to be careful when estimating things like mission time. For example, rather than using advertised thrust and Isp numbers, one needs to also consider the total amount of energy available (search Energy Information Administration data). When comparing available energy to mission kinetic energy, even an ideal “space drive’ (that has no propellant) faces serious limits.

    And that brings me to explain why we have the “incrementis” approach. Right now, if we wail until enough resources are available to do the big steps, we will be waiting a very long time and accomplishing nothing. Instead, if we do what we can now with the resources that are there now, we can chip away at the critical details. From that incremental progress, we are more likely to evoke the serious sponsorship for the big steps. If you did not discover it already on the site, ‘incrementis’ means; ‘in steps where each is bigger than before.’

    Someone has to start, now, and be prepared to fairly compare the options and what can be done with them – today.


  • Peter July 10, 2008, 18:22

    Have you given much thought to the details of the research institute- where it ought to be and the costs associated with it? How much would the location matter?

  • Marc Millis July 11, 2008, 7:39


    Regarding the research institute, sigh, there are so many variables at this point that it is premature to suggest single embodiments. As far as location, it has to be both affordable and a place where researchers would actually like to stay for two years and bring their family. As far as cost, that depends on the facility and number of positions, but tens of millions of dollars is a starting ballpark estimate.

    For an example of a similar idea that has folded (was configures as a commercial rather than philanthropic adventure), see StarLab:

    For an example of a philanthropic institute, this one devoted to just theoretical physics, see the Perimeter Institute.


  • Peter July 11, 2008, 11:24

    The obvious choice might be New Mexico or California, but given the universality of the knowledge involved and the global dispersion of materials and equipment needed, I’m not sure the location would matter a great deal, provided it’s in the developed world.

    Canada does have a good political and social climate for non-profits. It’s highly pluralistic and multicultural, lending itself well to physics, which is inherently trans-cultural. It also have easy access to both European and American markets for research material.


    Different technologies have different functions. You don’t venture across the Atlantic in a canoe. Vasimr is simply impractical for interstellar missions.

    Even if the obsolence factor doesn’t kick in after 4000 years, there are acceptable limits to people’s nobility in devoting their careers to something from which only distant future generations could benefit.

    This applies to fusion and fission as well. If it could ever be constructed, all data indicates that there isn’t enough hydrogen in space for an operational Bussard ramscoop. Without it, you’re looking at at best around .09c, which still isn’t practical for a mission even to Alpha Centauri (which, it might be added, has a very high improbability of habitable planets). Maybe it could be done, but who would want to spend their entire life in a highly confined space in deep space? Nobody sane, let’s hope. A decades long probe mission could work, but that sort of thing is already well within the domain of NASA and others.

    There’s only one subluminal option on the table for practical manned interstellar flight- antimatter. Everything else should be left to other space agencies.

  • Administrator July 11, 2008, 13:14

    Peter, I’ll agree strongly with you re Bussard ramjets but disagree with you on Alpha Centauri. The most recent work over the past few years strongly supports the idea of planets around both Centauri A and B. A few links to earlier Centauri Dreams stories on some of this material, much of it involving Greg Laughlin and team at UC Santa Cruz (Lick Observatory):




    but we’ve also looked hard at Elisa Quintana and Jack Lissauer’s studies of planets in binary systems in earlier posts. The odds on Centauri planets — including in the habitable zone — are looking better all the time.

  • andy July 11, 2008, 14:51

    The odds on Centauri planets — including in the habitable zone — are looking better all the time.

    Planet formation in Alpha Centauri A revisited: not so accretion-friendly after all


  • Administrator July 11, 2008, 15:48

    Interesting paper, and definitely running counter to other recent work. We’ll look at it here next week.

  • John Hunt July 11, 2008, 17:43


    Our goal is to advocate the development of Interstellar Travel. Mission designs are only a means to that end. So yes, we should be willing to set aside a favored design if another shows itself to better achieve the goal.

    The problem is that competing designs are numerous. How can TZF figure out what research it should advance if it hasn’t decided on what mission(s) are worthy? But to decide this there needs to be criteria for worthiness.

    This requires that subgoals be identified. I would suggest that the second-level goal should be “Sooner”. Or actually “The Soonest Possible”. Since this requires significant funding then I believe that the third-level goals would include:
    3a – “Cheapest Possible”,
    3b – “Likely to Succeed”, and
    3c – provide a sufficiently “Compelling Motivaion” (to spend the money).

    I think that there should be a periodic Interstellar Conference that would bring together the leading researchers in the field to present the latest information, review the criteria, evaluate the feasibility of proposed missions, identify worthy mission design(s), identify steps towards those design(s), and lay plans to advance the field. This process need not spend $5,000 per mission design for formal evaluation. Instead it could be something like where Practitioners were given five votes to distribute as they wish to competing designs. The top winners would then become the focus for progress. Advocates for competing designs could explain why their favored mission design best achieves the subgoals while challenging the competing designs in the spirit of collegial inquiry.

    What I am saying is that there needs to be a process whereby attention and effort can be focused. Even incremental steps need direction. Centauri Dreams is easily the best place to discuss interstellar mission designs. But it is a lot like a committee which never takes a vote. One can have fun discussing the options but it can’t get beyond that. There needs to be a selection process somewhere.

    Regarding energy/power requirements – If the Compelling Motivation is science return then power for return signals becomes an issue. If the Compelling Motivation is to preserve humanity then this is not essential. This is an example of why subgoals need to be determined.

    Regarding the total amount of energy available for launch – This matters for a science return mission since you don’t necessarily want to spend all that money only to have a later faster craft overtake it. For a preservation-of-humanity mission a slower mission is acceptable (buying the insurance earlier) but then issues of viability and complexity are raised.

    If subgoals are determined and attention is therefore focused upon creating a modern successor to Project Daedalus (i.e. a detailed study) it will be more likely to evoke serious sponsorship if the best design was clear, plausible (from a physics standpoint), and apparently within reach.

  • Marc Millis July 12, 2008, 13:33

    To John Hunt;

    I agree with you about the utility of conferences, and the utility of mission studies to keep the thought processes well-honed. I wish I had the time and money to set up a conference now.

    Regarding energy requirements, I seriously recommend that you look up the actual numbers and then run some calculations yourself to see what situation we are in. I have not yet had the time to take my own calculations and get them published, otherwise I’d point you to that publication.

    After you run the energy numbers it will become evident even if ALL options were functional today – even the breakthrough physics ones – we still face challenges on how to supply the missions with their required energy.

    That said, to focus on trying to launch (or even decide on) a mission as THE current activity is premature. Yes, mission studies are useful to vet options and to understand the most critical factors, but we are so far from having the resources to launch a mission that there are other places we should focus more attention. The resources, both in funding and in energy for interstellar missions, are just not there – period.

    Meanwhile, numerous very clever people have a whole host of ideas of how to approach individual parts of the problem. In the course of working on those ideas, students have become practicing engineers or scientists, ideas for solving other problems have been generated, and even some companies formed. For example, there are two companies that deal with antimatter research, both of which have examined interstellar missions only as side issues. The folks that are actually making progress are the ones that focus on their particular next-steps rather than burning their time advocating for funding a mission.

    I have been to many conferences where most other researchers are basically giving sales pitches on why their version should be funded over the others, and the arguments are in terms of the ultimate mission utility. As I just said early, this is premature, since ALL interstellar missions are currently out of reach. And, there is NO funding for a mission. Instead of actually making progress on their ideas, they focus their personal energy into the sales pitch and comparisons to their competition. Hence, they make very little progress.

    I have been in situations of seeing both these scenarios played out and it is from that experience that drives me to set up Tau Zero they way that I am. I’m setting things based on seeing what produces the most progress. Focusing on taking the next steps is more productive than arguing about choices for missions that cannot be supported.

    Yes, there will be a selection process – once we have sufficient funds – to decide whose research to support, but the choice will be rooted in who can make the most progress rather than trying to down-select to a mission configuration. While it is fare game that mission studies be included in that set, it is understood that such exercises are to better understand the pivotal factors rather than on picking THE mission configuration.

    If you’ve been in the propulsion research community, you might have seen the kind of stalemate things are in, and its not just about the funding. Tau Zero approach aims to break that stalemates by changing how things have been done, to copy the more successful practices.


  • John Hunt July 13, 2008, 3:17


    > I wish I had the time and money to set up a conference now.

    Could one start by having a mini-conference by adding an additional day onto an existing conference which a number of interstellar researchers might already be going to?

    > we still face challenges on how to supply the missions with their required energy.

    Isn’t it true that:
    – short mission times = high energy needs, and
    – long mission times = low energy needs?

    We had enough energy in 1977 to launch Voyager 1 on a 77,000 year mission to Alpha Centauri distance. Clearly 77,000 years is too long for viability. But we have enough power today to launch an IIE which would take about 42,000 years to reach A.C. Still too long. But this illustrates that energy itself is not a show stopper IF:
    1) we have a sufficiently compelling rationale for a long duration mission,
    2) craft viability at destination, and
    3) sufficiently low likelihood of mission failure at destination.

    If we limit our missions to science return only (i.e. meaning mission times of 50 or so years) then yes, we’d need a tremenous amount of energy. This is likely much more than we can afford today regardless of mission design. But the energy needs of preservation-of-humanity missions are based upon viability issues rather than life-time-of-researchers issues.

    > better understand the pivotal factors

    All I am asking is that due consideration be given to:
    – long-duration craft viability,
    – reproductive biology,
    – and automated habitat construction, life support production, & childrearing
    as potentially pivotal factors and that:
    – launch energy, and
    – short mission times
    MAY not be pivotal factors after all.


  • Ronald July 13, 2008, 6:11

    @andy Says:

    July 11th, 2008 at 14:51
    The odds on Centauri planets — including in the habitable zone — are looking better all the time.

    Planet formation in Alpha Centauri A revisited: not so accretion-friendly after all



  • Ronald July 13, 2008, 6:15

    Sorry, I could not help the Homer phrase when I read the bad news.

    But seriously, it is only about Alpha Centauri A, the odds for B are still about as good.
    Curious to learn what the Quintana and Lissauer response will be.

  • george scaglione July 13, 2008, 12:48

    i agree with what marc has said above.tau zero does seem to be for now the best bet those of us interested in potential star flight have.i myself have from time to time tried to “sell” ideas of my own regarding these subjects. which of us has not?we certainly must give these subjects alot more thought and discussion.the very best to all of you my friends, george

  • Administrator July 13, 2008, 13:24

    We’ll be looking at the Thebault et al. paper on Centauri A tomorrow — Ronald, you’re right about Centauri B, as the authors point out. More later.

  • Paul Titze July 13, 2008, 13:36

    Hi everyone,

    Just following up on Marc’s comments regarding conferences (maybe Paul might have already mentioned this before), in case readers aren’t aware there’s a very interesting Space, Propulsion & Energy Sciences International Forum or SPESIF-2009 coming up which includes the 6th Symposium on new frontiers in the space propulsion science:


    I’ll be very interested to read the papers that come out of this meeting especially from A03 “Frontiers in Propulsion Science”…

    Cheers, Paul.

  • andy July 13, 2008, 15:04

    Indeed, the planetesimals-to-embryos phase has not been simulated for Alpha Centauri B. I posted the comment more as a response to the ever-improving odds remark, rather than as evidence to rule out the Alpha Centauri system as a whole.

    Though while we’re discussing limits on planets around our triple system neighbour…

    Toward detection of terrestrial planets in the habitable zone of our closest neighbor: Proxima Centauri

    …which brings home just how much planet detection has improved, that planets with m*sin(i) more than about 2-3 Earth masses can be excluded in Proxima’s HZ.

    (Of course, massive planets could exist if they are in face-on orbits)

  • Tibor July 13, 2008, 15:52

    Just two quick hints:

    * one on conferences
    The Aosta-conferences “IAA Symposium on Realistic Near-Term Advanced Scientific Space Missions, Missions to the Outer Solar System and Beyond” have usually quite a lot of interesting topics re our (precursor) interstellar stuff. The Aosta 2007 papers (this was the 5th Symposium, the 6th is being planned for 2009) became just available in the August 2008 issue of JBIS, abstracts online here:

    !!! (Paul, the BIS server seems to have some problems now, I cannot access the website; I will try it a bit later to get the weblink; or if you have access, could you put it in please. Thanks, Tibor)

    * one on SF as innovative thought-provoking tool
    “Innovative Technologies in Science Fiction for Space Applications” was an ESA project several years ago, here a quote from the Study Goals:

    “The main objective of the ITSF Study was to review past and present SF literature, artwork and films in order to identify and assess innovative technologies and concepts described which could be possibly developed further for space applications.”

    See more on the web at http://www.itsf.org


  • Tibor July 13, 2008, 16:39

    Here the BIS link to the Aosta-papers:



  • Marc Millis July 14, 2008, 7:01

    Regarding prior conferences;
    Yes, the prior Aosta set was good. There was also a substantive workshop at JPL on “Interstellar Precursor Missions,” I think in 2001(?) And then there was Belbruno’s NYC conference in 1994 – also good. Belbruno’s was documented in a series of JBIS articles that may have come out a year or two later.

    Regarding future conferences;
    For reasons too complex to explain, I cannot support the SPESIF-2009, which grew out of the now defunct STAIF sessions.
    I have been discussing options and formats to convene an international interstellar workshop with some of my cohorts, but it takes roughly 1 year in advance to plan. Adding days to other venues is a viable option and considerations toward that are being explored. Travel support is an issue since the folks we deal span international locations. This also makes it more complex when picking a workshop location. But right now, the real impediment is having enough support to finish launching TZF so that we can move next to such details.

    Regarding John’s:
    (begin quote)
    All I am asking is that due consideration be given to:
    – long-duration craft viability,
    – reproductive biology,
    – and automated habitat construction, life support production, & childrearing
    as potentially pivotal factors and that:
    – launch energy, and
    – short mission times
    MAY not be pivotal factors after all.
    (end quote)

    John, the above list is reasonable. What I thought you were emphasizing earlier was the urge to try and pick the best mission configuration options ‘now.’ The list above, where various factors and options are explored in more depth (with no hurry to pick ‘the’ best option), is more along the lines of what I want TZF to accomplish.


  • John Hunt July 14, 2008, 18:58


    I think that a balance needs to be struck between keeping our minds open about options (including options that are yet to be thought up) and the favorable impact that highlighting a specific mission can have. The BIS decided to task a group to come up with a specific mission to reach Barnard’s Star; hence Project Daedalus. They focused upon one mission and yet I don’t think that this did anything at all to slow the development of later (and perhaps better) concepts.

    Yet, what was the benefit of BIS highlighting a specific mission? Undoubtedly they got considerable press in both scientific and lay publications. An actual interstellar mission is too far off the radar screen for both aerospace engineer, the public, and the government. Given the tremendous technical and financial challenges, I can hardly blame them.

    I would never suggest that TZF stop exploring a variety of concepts. The reality is that as a group we really don’t know which concept will turn out the be the actual first truly interstellar mission. We do need to keep an open mind.

    But I believe that TZF or whoever needs to collectively struggle with goals and subgoals and then pit concepts against each other as to which are stronger or weaker in achieving those goals. And then highlight those concepts which are the most plausible in order to move engineers, government, and the public to believe that an interstellar mission is not pie-in-the-sky and should actually begin planning for the “Beyond” part of the “Moon, Mars, and Beyond”.

  • Peter July 15, 2008, 7:42


    I don’t expect you to argue with what I’m about to say, since I know I’m not going to change your mind, and you’ve already expressed your views on the matter. I just want to clarify- for others and myself- why, although I admire your idea and wish it all the best, I stand where I do.

    Your position has much to do with the theory vs. experiment debate. You’re obviously on the side of experimentation, but I would argue that theory has already shown us enough about solar sails, VASIMR, fission, fusion, etc. to be able to discard all these as being impractical and a waste of time when investigating interstellar technologies. No more experimentation- or theory- is necessary to redeem their viability in this area.

    As you say, you’re far more attuned to how things have been going in the propulsion community, but particularly when seeking funds, the clarity of objectives and the clarity of the means to those ends- based on what is known- is extremely important. You say the resources, in funding and energy, aren’t there to justify mission-centric approaches. But what about the theoretical knowledge? If we really are ready to make the transition from theory to experiment, then a high degree of specificity is in order- without which we don’t yet belong in the lab nor do we deserve funding.

    I applaud those energetic researchers making competitive “sales pitches” at conferences- I shall soon be one of them- because without them there may be no progress to be made. Indeed, the problem may be that they’re not energetic and competitive enough. What they’re doing is only premature if they haven’t studied hard enough and come up with an organized enough plan. Without that, it is your blindly chipping away at things that may be premature, and pointless. Your incremental approach implies either a lack of good theories or a lack of theoretical rigour- either of which make costly experimentation unwarranted.

    All interstellar missions may be out of reach, but based on what we already know, some ideas will most definitely be permanently out of reach (or at best always impractical, no matter how much research is done). We CAN set specific parameters, based on clear objectives, drawing on hundreds of years and countless papers of existing theory, instead of going down obscure alleys which are known beforehand to have substantially less promise and practicality- even in the event that experimentation yields more promising results than were theoretically known. Having focus and aiming before shooting only maximizes the possibility of better results,in accordance with ultimate goals. It also fosters an atmosphere of clarity and direction.

    I submit that the ultimate, sole objective should be a manned mission, at a minimum speed of .3c. That puts at least a few stars within range of a typical astronaut’s career time, making the chances of finding a habitable world (without which there is substantially less justification) quite reasonable, based on available data. Much can be gained scientifically from lesser interstellar goals, but they don’t justify a seperate visionary organization.

    This rules out all known sub-C ideas except for antimatter, so that should be the first thing to focus on. Do you have any evidence that any of the other sub-C technologies we’re discussing could, with experiment, defy existing theory and reach this goal? (I believe I can theoretically prove that they never will, without ever stepping foot in a lab, but that would take some time, and as I said, doing so wouldn’t change your mind and your approach anyway).

    At any rate, I will continue work on my plan. In addition to this lack of focus, my basic problems with the road that TZF is taking are with the anti-government bias (substituted with what I perceive to be unnnecessary proto-bureaucratic hurdles), the commercialism, the credentialism, and what, regardless of intentions, can be seen as the dumbing down of the content (both philosophy and science fiction should be avoided- philosophy because physics and engineering is intrinsically trans-ideological and because people can decide for themselves their own relevant philosophy, and science fiction because it attracts crackpots). These may turn out to be assets rather than liabilities, who knows, but I’d prefer a different model and I believe it’s possible.

    If there emerges two non-profits committed to similar goals, I can see that as only a good thing. Like having two habitable worlds, it increases our civilization insurance two-fold. If I manage to organize something, it could act as an alternative, attracting those favoring a fundamentally different approach, focusing on different research with a different structure- different means to similar goals. So there could be opportunities for cooperation, less so for competition.


  • Adam July 15, 2008, 15:47

    Should an interstellar program aim to colonize habitable planets? Would anyone stomach the idea of trashing another biosphere in this day and age?

  • Administrator July 15, 2008, 16:30

    It’s a reasonable question, Adam. I suppose my answer would be this: If we can get our environment under control here on Earth, we should be able to do it on other planets as well. And if we can’t — if we truly destroy our own biosphere — we won’t be around to be concerned about other planets anyway. Bleak thought…

  • andy July 15, 2008, 17:07

    If we can get our environment under control here on Earth, we should be able to do it on other planets as well.

    The problem is that getting the environment under control is not the relevant issue. The experiences on Earth of introducing non-native species is not particularly promising from an ethical point of view, and when colonising a life-bearing planet this kind of introduction is pretty much the point of the endeavour. Either we get a rabbits-in-Australia situation, or the alien biosphere has nasty effects on us, both scenarios having severe ethical problems.

  • Administrator July 15, 2008, 18:31

    Either we get a rabbits-in-Australia situation, or the alien biosphere has nasty effects on us, both scenarios having severe ethical problems.

    Yet another reason why a foundation like Tau Zero should have a strong philosophical and ethical component.

  • John Hunt July 15, 2008, 19:49

    Peter seems to make several good points. Funding for research should be directed to where it will do the most good. This means evaluating the various concepts and determining which are more worthy than others according to established criteria. I would also agree that there are some theoretical concepts which are known to be impractical. Clarifying which are impractical and why would be helpful for multiple reasons.

    > I submit that the ultimate, sole objective should be a manned mission, at a minimum speed of .3c.

    Yes, it is the ultimate objective of interstellar space flight for living humans to travel about .3c to habitable worlds. This is a rather high standard which I don’t expect we’ll get to until probably into the 22nd century. But prior to this ultimate objective we should be able to achieve the same goal of establishing human colonies in other solar systems at much less cost and risk by sending our colonists as frozen embryos requiring:
    – much lower launch energies,
    – practically zero life-support maintenance in transit,
    – much lower risk of loosing the life of our astronauts.
    So I would not make the ultimate objective to be a sole objective unless provided with a sufficient rationale.

    The focus of our efforts should be on the first interstellar mission rather than later missions or even a multitude of concepts including those with little likelihood of being the first interstellar mission.

  • John Hunt July 15, 2008, 21:06

    Should an interstellar program aim to colonize habitable planets? Would anyone stomach the idea of trashing another biosphere in this day and age?

    Yet another reason why a foundation like Tau Zero should have a strong philosophical and ethical component.


    Such hypothetical concerns might seriously inhibit progress. For example, there might be native bacteria on Mars. If we are too concerned about harming Martian bacteria then that could put the kibosh on Mars colonization! Imagine what delays would be introduced if a planet had to be certified as being bacteria free before any development could occur there?

    I really wouldn’t want Tau Zero to have so strong an ethical component that it began becoming distracted by exobiology issues of target planets. The odds that nearby solar systems have any life is small in my opinion. And if life is so common that it evolved independently within 10 or so light-years then life exists just about everywhere and so life is so common that it become less special. By this I mean that if there are a billion planets with bacterial life, what is the great loss if that is reduced to 999,999,999? Especially if one thinks of a second solar system being used for for the benefit of an intelligent civilization.

    Also, many types of environmental degredation follow a “hump” curve where a large population becomes more technologically advanced and so impacts the environment more. But with development it becomes more efficient and introduces more environmental protection. Acid rain, the water quality of streams in the US is one example and air pollution in some places is another. The nice thing about establishing a colony on an abiotic planet in another solar system is that it will start out with a small population but with advanced technology. Also, without a biologic history, there would be no fossil fuels. Energy would be largely renewable or nuclear in which the waste is localized.

    I think that the ethical demand of securing a second, distant home for humanity trumps the unlikely and small ethical dilema of possible harm to exobiology.

  • James M. Essig July 15, 2008, 23:36

    Hi Marc and Paul;

    I have just viewed the new webpage for Tau Zero. What can I say? The art work is outstanding and inspirational. The introductions are written in a very bold and inspirational manner. After paging through the menu options, my emotional reaction reached to the core of my psyche. I am thinking that Tau Zero is going to be big. I can tell much work went into the beautiful new format of the Tau Zero website. Many thanks to both of you Paul and Marc for providing this venue for all of us space heads. Job well done!

    Many Thanks;


  • Marc Millis July 16, 2008, 8:53

    Peter, John, et al;

    After re-reading what we’ve each wrote, I think I’ve been missing some of your points and responding in the wrong way. There are some good suggestions in what you’ve expressed. It might be reciprocal too – it is quite likely that you’re also missing what I’m really gettign at, especially when I read what I wrote and find that I’m not really saying things well.

    It appears that we all want to accelerate progress. Although we might have different emphases on details – and even here we are probably in more agreement than I originally thought – the overall point is that we each want to do what we can to succeed.

    Bear with me on how this is all going to play out. It is quite likely that our practitioners will also work on mission assessments – like revisiting Daedalus with contemporary technology projections – in addition to details of particular approaches.

    Right now about all we’ve done is get a high-quality pool of talent together, and worked on the side to help each other publish relevant works (which have not yet been listed on the site). The fledgling website is the next step and there is so much content that has not yet been posted. For example, it would be prudent to have a section on the old Daedalus, and to Forward’s light-sail studies.

    Since we are finding it more difficult than anticipated to produce Tau Zero content in addition to day-jobs, I’m hoping that the modest donations that we can now receive will enable my cohorts to add more content – so that everyone can see what has been and has not been done… and then to see how these compare evenly, without the salesmen spin of a pet approach.

    And to Andy and Adam about the issues of placing humanity on another planet, this forum is precisely the venue through which to examine such issues. It is an issue. That is why sociological topics will also be covered at Tau Zero. That is another gap needing to be filled.

    And that brings me to the final point – of HOW to make all these things happen. If any of you have succeeded in making progress beyond your peers on these topics, please let me know what you did differently to succeed while the others languished. The tactic of learning from the successes and failures of my contemporaries is where I am getting my insights as to how to run Tau Zero.

    And if you need any evidence of my abilities to succeed where others have languished, look at the unfinished physics of warp drives and gravity control. When I started, that topic had a huge giggle factor and it was virtually impossible to make progress. Now, we are at the point where the first-ever technical book is about to be published and I succeeded in getting the volunteer support of 17 other professionals to devote significant time to make that happen. There were even more steps in between, but these two end points should make the case. My work has also made it easier for others that I don’t even know to start tackling these topics.

    I want to do the same thing with Interstellar Flight in general – to make progress where others have languished. I am drawing on the experience of seeing the difference between the more and less successful. And now, from our recent exchanges I see that there is untapped potential out there amongst the readership. By opening this up on the Internet I see that we’ve opened another tool whose potential can be tapped.

    Please be patient as we continue to adapt and make progress. Your suggestions are helpful. It would also help, if you see how Tau Zero is the place that can really make things happen, that you financially support the work too.

    Thank you,


  • John Hunt July 16, 2008, 17:42


    You know how it is that you think up an idea and then run it past a friend. During the conversation he asks clarification, challenges assumptions, and suggests variations. The end result is that your idea evolves and becomes stronger for having been so critiqued. This is a two-way street, of course and we are all better off for being part of a community with independent minds and with somewhat different perspectives.

    What Paul, you, and others are doing both on the web and professionally form the core of efforts to actually move things towards a true interstellar mission. Centauri Dreams provides the best forum for discussing such matters and, I believe, will help bring the initial interest group to Tau Zero.

    Not being a science or engineering professional but just a “space head” I struggle with wanting to help in some way but also don’t want to overly consume the time of the professionals by seeking too much discussion of ideas.

    Conceptually throwing together an organization and a functional website is easy. Doing it in reality is often much more challenging. You have my patience.

    In addition to small financial contributions, is there anything else that we non-professionals can do to help? Can we pull together, organize lists/links of articles? Can we track down links to pictures? Compile contact info of potential members? Design ads?



  • Marc Millis July 17, 2008, 8:53


    Thank you for your supportive words.

    The challenge of tapping into the potential of the enthusiasts is indeed something we’ve pondered about. As time goes on we hope to learn more from our interactions with enthusiasts to figure out how to best help them (you) help the general cause.

    For now, there are 2 things we can ask of the enthusiasts in addition to the obvious request for financial support:

    (1) Let us know which books, web sites, or whatever, that you consider the BEST information – only the best. With that, we can post those links or learn to emulate the styles of the publications that have the most impact.

    (2) Continue to educate yourselves, especially with formal schooling. This will improve the overall quality of interactions. If you educate yourselves through Internet information, learn to filter our the questionable information from the more reliable information. One of the quick distinctions is the correlation that the grander the claims, the more questionable the material. Another clue is if the site offers reference citations so that their assertions can be checked. Also, if you have not already started, begin to read articles in respected journals. On the topic of Interstellar Flight, the Journal of the British Interplanetary Society is a good place to start.

    As we proceed with implementing Tau Zero, we hope to come up with more ideas too. I can relate to that feeling of wanting to get in there and do something, rather than to just watch others doing it.



  • Marc Millis July 17, 2008, 8:57


    I forgot that there is a 3rd one too:

    (3) Tell us what you need to have explained to you. What are the most confusing topics or where you feel there is a void in reliable information? With that, we know where first to concentrate our information.


  • george scaglione July 17, 2008, 13:54

    marc i feel that the comments i want to make fit right in with the points you have made above and at the very least might cause some thought among the persons who visit here. i cannot help but notice as i say that the quality of this site has quite literally redoubled in the past few weeks. so then, i had this idea : concerning the ability to go faster than light in the normal space of which einstein spoke,what if it where somehow possible someday to fit a starship with a field projector capable of making a tear in spacetime just in front of it so that it would be possible to sweep space in front of itself by continually flying into a parrallel and hopefully completely emtpty dimension.the propulsion might be,matter/anti-matter,fusion,or even something i had mentioned afew months ago myself,the use of the enegy of the zpf itself as the motive force.economical in that you do not have to carry fuel and that your fuel would be everywhere as you traveled.now i know that these ideas in and of themselves are most probably at this juncture impossible,but someday the mountain of engineering problems represented therein might “easily” have been scaled.i would not even bet that there is not currently an alien species somewhere out there that can do these things today. just brainstorming eveyone…in the hope of getting some more opinions.starflight is to me it should go without saying a very important subject. very respectfully,your friend george scaglione

  • James M. Essig July 17, 2008, 14:54

    Hi George;

    Fascinating ideas! Keep up the thinking with respect to the sweeping of the space in front of a ship and continually flying into a paralell dimension. The effect might be compounded or multiplied if there exist an unlimited number of paralell dimensions in which to continually fly into. Excellent ideas, George! Keep up the good work.

    To the readership in general, I would like to recommend the ABC Online News site for almost dailly reports regarding manned space travel and robotic space exploration currenntly being undertaken and/or for which concrete plans are being made and actual large scale funding is current. Some such projects are obviously the CEV and the Orion craft that will take U.S. astronaunts back to the Moon by 2020, the updates regarding the Pheonix Mars Probe, and the other manned space efforts being made by other world powers such as Russia, the EU, China, India and the like. These are precursor efforts and plans for the future of humanity in space which hopefully involves the eternal radiation of mankind ever further out into the cosmos.


    Your Friend Jim

  • Marc Millis July 18, 2008, 7:50


    I just thought of a 4th one too (Ways that enthusiasts can help in addition to financial support):

    (4) When really provocative and insightful discussion happen via these comment venues, it would be incredibly helpful for external volunteers to take those discussions and distill them down into their essential, SHORT, points. We could then post these focal point summaries for others to quickly grasp the span of discussions.


  • george scaglione July 18, 2008, 9:13

    jim,marc,thank you both very much for the fine support of our joint venture here and all of the ideas we are all trying to promote,it is a pleasure to be able to come here to see what is up with this project which vitally concerns us all. george

  • andy July 19, 2008, 6:55

    Regarding the issues and ethics of encountering alien biospheres, it might be better to target “cold-start” habitable planets around subgiant or giant stars for colonisation missions. Such systems have numerous advantages:

    • The system has been around a long time, which means there’s been a lot of time to clear out the system’s small bodies (obviously there will be some asteroids remaining, but the more grossly unstable stuff will have gone), resulting in less impact risk on the planets.

    • Geophysical hazards such as natural fission reactors and intense volcanism would be less likely on older planets.

    • The amount of time the planet has already been habitable would be relatively short, meaning there’s less chance that life has evolved into environments where it would come into contact with humanity.

    The nearest such star is the F-type Procyon (11.4 light years), however it does not look like a good target due to the white dwarf companion star: before Procyon B lost mass during the red giant stage, the system would have been a closer binary, and the current habitable zone is already getting near the stability limit.

    Beyond Procyon, there are the G-type subgiants Delta Pavonis (19.9 light years) and Beta Hydri (24.3 light years). The nearest giant star is the K-giant Pollux at 33.8 light years, which is already known to host a giant planet.

    These distances may seem a lot compared to the Alpha Centauri system, but Delta Pavonis and Beta Hydri are the 5th and 7th nearest G-type stars to the Sun, and the 3rd and 4th nearest solitary G-type stars (after Tau Ceti and 82 Eridani), so it would seem that for a colonisation mission, a design which can travel across a distance of 20 light years or so is necessary to ensure that there are enough potential targets.