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Centauri Flyby: The Ultimate X Prize?

What should be the goals of the next generation of X Prizes? Peter Diamandis is just the man to ask the question. It was Diamandis’ foundation that led to the launch of a private manned spacecraft in 2004, and since then his team has gone on to sponsor an automotive X Prize offering $10 million to anyone who can produce a marketable car that can get 100 miles per gallon. Sixty teams are at work on that one, and prizes focusing on renewable energy are also in the works. The big fish in the pond is the Google Lunar X Prize, which offers $30 million for the first privately funded robotic mission to the Moon.

Nor is Diamandis alone. In fact, the landscape is awash in prizes. The Virgin Earth Challenge, brainchild of British aviation mogul Richard Branson, offers $25 million to anyone who designs a viable way to remove greenhouse gases from the Earth’s atmosphere. For that matter, what about the Saltire Prize, for which Scotland has found £10 million for renewable energy breakthroughs? The US Department of Energy is in on this act as well, with $4 million in the offing for the winner of the Freedom Prize, designed to reduce US dependence on overseas oil.

It’s no surprise, then, to find Diamandis pondering what a truly long-term X Prize might look like. On Friday, he’ll discuss ideas that are seemingly impossible but could change the world in a talk sponsored by the Long Now Foundation in San Francisco. If you’re unable to be there, Diamandis has put a video up on YouTube asking for input on the question (you can send in your thoughts here). He wonders what would have happened if, in the 1870s, someone had offered a major cash prize for a heavier than air flying machine, or a way to communicate instantly between London and New York: “People would have thought you were nuts, that these are literally impossibilities, magic.” But we know the outcome.

A future X Prize, Diamandis opines, might be focused on a colonizing mission to Mars. Or it might involve transforming energy into matter (here he recalls Star Trek‘s transporters). Maybe we can take the prize notion to outrageous limits and suggest an interstellar component. Heck, we’ll even offer a head-start. In a recent post on his systemic site, exoplanet hunter Greg Laughlin offered an interesting comment on Alpha Centauri, one worth keeping in mind for would be prize designers:

We’re fortunate that we’ve arrived on the scene as a technological society right at the moment when a stellar system as interesting as Alpha Cen is in the very near vicinity. During the last interglacial period, Alpha Cen did not rank among the brightest stars in the sky. A hundred thousand years from now, the Alpha Cen stars will no longer be among our very nearest stellar neighbors, and in a million years, they will have long since faded from naked-eye visibility. At the moment, though, Alpha Centauri is drawing nearer at 25 km/sec, a clip similar to the Earth’s orbital velocity around the Sun. It’s as if we’re on the free trial period of an interstellar mission…

A free trial period is usually enough to quicken the pulse of consumers. So why not use it to tantalize potential prize donors with the prospect of a truly long-term, outlandishly expensive prize, one designed to spur efforts to put a man-made payload with the capability of returning scientific data into the Centauri system? The data returned could well prove less significant than the breakthroughs achieved to make the journey.

Prizes capture the imagination and can create new ways of thinking because the people involved in them often put far more time, energy and money into the process than the prize itself justifies. You wanted long term, Peter, so how about a Centauri Prize for the first interstellar flyby?

Comments on this entry are closed.

  • devicerandom September 11, 2008, 14:53

    I don’t understand why a flyby. While a lot of interstellar voyages are thought as flybys, I wouldn’t recommend so.

    I am no expert, but I think every technology used to propel an interstellar vessel can be used also to brake it when it comes in vicinity of the star system. Just turn by 180° and your solar sail/Orion nuclear pulse/whatever should help you get in orbit around Alpha Centauri. If I am naive and/or plain wrong, I would like to know.

    Given the extremly high difficulty of such a mission, I think we should strive for it to be as rewarding as possible -think of years of data from orbiting the Centauri system, perhaps using residual energy from the interstellar travel for interplanetary travel between the Centauri planets/asteroids, instead of just a few days crossing before being lost into the Galaxy.

  • Administrator September 11, 2008, 15:03

    devicerandom, the problem here is that if you’re using, say, a beamed laser for propulsion (and not the much slower solar sail), you have to find a way to reflect laser light back onto the sail even though the spacecraft is moving outward from the Earth. Robert Forward did come up with a way to do this, but it’s tricky. The same problem applies to particle beam methods.

    If you’re using nuclear propulsion of some sort, you run smack into the equations that govern rocket flight, and the problems are huge. Remember, if you want to carry an equivalent amount of propellant so you can slow down at the other end of the mission, that means you have to increase your initial propellant enough to lift that additional mass. The numbers go right off the charts, a good reason for choosing methods that leave the propellant back home.

    Marc Millis once worked out the calculations based upon an efficient ion engine. Figuring on 500 propellant tanks the size of supertankers to make the flyby, Millis then contemplated what would be needed for a rendezvous mission. The equations are intractable: If we want our spacecraft to stop once it reaches Alpha Centauri, those five hundred supertankers would need to be supplemented by another three hundred million supertankers to make the hypothetical 100-year journey. The problem is the need to keep adding more propellant to push the propellant you need later for the rendezvous.

    A good source on all this is the Matloff/Mallove book The Starflight Handbook. Here’s a snippet that’s germane:

    “…the rocket’s fundamental problem is that so much energy needs to be expended just to boost a large amount of propellant to a certain velocity so that that propellant, in turn, can give the remaining propellant and structure an incrementally higher velocity. Moreover, the requirement for propellant mass does not simply increase proportionally to the final velocity ΔV that the vehicle must achieve, but exponentially.”

    That word ‘exponentially’ carries a world of trouble for mission designers.

  • tacitus September 11, 2008, 15:07

    I have to ask the obvious question. Given that it will likely cost billions of dollars just to make it to the starting line of an interstellar mission, is there a sum of money large enough to be an effective prize and incentive? Someone capable of launching such a mission isn’t likely to be moved much by $100 million or more.

    Now, if you were to offer a long term prize for the development of an engine technology that could power a spacecraft up to a certain (small) percentage of the speed of light. you might be able to set that winning parameters to something that, while still very difficult and expensive now, might be achievable by companies of more modest means in the future. 1% would be a nice round number, for example.

    This is the type of thing proponents of the space elevator are doing. They are not offering a prize for the first completed space elevator (again, if you can do that, you don’t need the prize money) but they are offering prizes for breakthroughs in technologies which will be used by a space elevator one day. I think focusing on similar competitions for interstellar travel would certainly have merit.

  • Administrator September 11, 2008, 15:17

    Sure, I agree with you, tacitus. I was just responding in the spirit of the Diamandis video, where he talks about major projects (he even mentions exceeding lightspeed!). But advancing technologies incrementally is an idea I personally get behind because it’s the one that’s likely to produce results. Hmmm… ad astra incrementis — where have I heard that before?

  • Tibor September 11, 2008, 16:52


    this is the stuff I was smoking as I made my prediction :-)

    Ansari X Prize: 1998-2004
    Google Lunar X PRIZE: 2007-2014
    (Long Bets) Centauri X PRIZE: 2009-2025

  • Adam September 11, 2008, 19:33

    A Stairway to the Stars of X-Prizes might be one option.

    (a) SPS demonstrator

    (b1) Self-replicating SPS

    (b2) Maser/Laser/Particle Beam/Mass beam propulsion demonstrator

    (c) Interstellar flyby

  • John Hunt September 11, 2008, 19:45

    Very interesting stuff!

    For an interstellar mission to be of any value, humanity needs to survive long enough. I would suggest that an XPrize addressing existential threats should be a necessary counterpart to any long-term XPrize.

    Also, why specifically challenge people to a flyby mission? Obviously that would be scientific only. Doing so gets us into the Wait Equation problem and doesn’t have a compelling rationale such as the SURVIVAL-OF-HUMANITY imperative. If an interstellar mission can be linked with a survival rationale then interest can be generated, money can be attracted, near-term missions can be focused on, and hey, it might actually spare humanity to live again in a neighboring solar system.


  • Administrator September 11, 2008, 20:22

    John, good points. I used a flyby mission because, although no Centauri mission could exactly be called ‘cheap’ (this is perhaps the understatement of the century!), a flyby at least constrains the propulsion problem, as per my note to devicerandom above.

  • Tibor Pacher September 11, 2008, 20:26


    It is really crazy – I was preparing during the week a letter to Peter Diamandis (cc: Danielle Engelman of The Long Now Foundation), still before he makes his talk to the Long Now folks…

    …and I am of course, not ready.

    But You know my attitude to prizes and “think big” – so why do we not address the issue to Peter Diamandis directly? Come on, let us approach him!

    I have just collected some arguments re a possible realistic (Mega) X PRIZE with terms similar to our Long Bet`s ones – here they are:

    * after the Google Lunar X PRIZE the next really captive challenge (for unmanned flights) for space exploration is an interstellar flight (a manned Mars mission is probably much more expensive than a first interstellar probe!); maybe with a prize of 50 (or 100) Million $

    * 18 Long Bets on the record (25 right now, 5 of them with indefinite timeframe, shortest and longest ones ignored) have an average bet time of 18,4 years

    * the time frame 2009-2025 (or similar) would fit perfectly in the series Ansari X PRIZE (1996-2004), Google Lunar X PRIZE (2007-2014) for Space Prizes

    * there are several promising technologies on the table board which could be capable of delivering the necessary propulsion system, e.g. solar sailing (with a sundiver manoeuvre) and VASIMR to win the bet in this time frame

    * even if no one would win the prize until 2025, a huge boost for interplanetary flights would come, and the breakthrough for the utilization of the Solar System would be made

    * such a prize could lead to “an Apollo programme” for the whole Earth (Faces from Earth!) – yes, I am dreaming of such a thing –



  • Ron S September 11, 2008, 21:38

    Combine the above ideas:

    Make the prize for the capability (or actuality) of flight to A Cen within an average human lifetime.

    You can develop rapid travel or extend the average human lifetime, or any suitable combination of the two. Then we can win two ways from the spin-offs.

  • Adam September 12, 2008, 8:26

    The NSS has announced an experiment with power transmission from one Hawaiian island to another through 158 km of air. That’s more than a power-beam has to struggle through coming from GEO. I’d be very interested in the power levels and efficiency they’ll achieve.

    Just one small step…

    How about an X-Prize step demonstrating 100 MW power beaming to a VASIMR equipped vehicle or some such? Or a Benfordx2 desorption sail? Geoff Landis has a paper on power-beaming to power an ion-drive probe – which is better performance wise than a laser-sail below 0.2 c.

    If we think laterally enough all sorts of interstellar related X-Prizes can be dreamt up. Why not $10 million to IMAGE a planet around Alpha Centauri?

  • tacitus September 12, 2008, 15:36

    Yes, I like the more practical “intermediate” prizes that focus on breakthroughs in technology instead of ones that basically would require a government or a multibillion dollar corporation to have a chance of winning.

    One possibility, though, would be to start a long term prize, the kitty of which is added to by, say, $10 million every year. Then after the first couple of decades (or more) the rising (compounded) prize money and the falling cost of technology could converge to make the prize worth competing for by a larger group of companies and wealthy individuals.

  • JoeP September 12, 2008, 15:51

    I’m not sure I like the idea. Unless there is some sort of propulsion technology breakthrough that is drastically less expensive than rockets — AND is something that works an order of magnitude better than the best rockets, nobody is going to be able to spend the kind of money needed to attempt such a flyby. We are talking billions of dollars.

    Even if some organization could somehow offer vast sums as incentive to the winner, I doubt that any organizations or companies would see the value in spending even a hundredth of that amount just to see if they could win the prize.

    I see the current X-Prizes more as an affordable PR enterprise for firms and startups (“see how great our engineering is?”) rather than genuine incentives to further space exploration technical advancement. The competitors take current technologies and make them a bit smaller and cheaper rather than try to invent completely new ways of doing things.

  • Will Baird September 12, 2008, 16:09

    As an X Prize participating team leader[1,2], and hopefully double participant, I think you guys need to scope this a bit. Yes, Diamandis called for some extraordinary ideas. However, there needs to be a goal that is difficult, yet achievable.

    Why not a long term space probe? Think of it as an intermediate between your AC flyby and what we do now.

    The probe must last 30 years.

    It must be autonomous.

    It must rendezvous with multiple bodies. Bonus money for different classes of bodies with the same probe.

    It must do a certain amount of science, not just take pix.

    The prize will be doled out in chunks /as/ requirements are met. Past 10 years and done 2 rendezvous is for x amount of money, each additional rendezvous y amount, each additional 5 years, z amount, etc.

    Bonuses for visiting outer planet moons, comets, asteroids, etc in the same mission.

    This /might/ be a way for a survey of the asteroid belt to be done. Or at least a way to demonstrate technologies for such long term missions.

    Just a thought…

    Will Baird
    Team Leader
    Team Phoenicia

    1. http://space.xprize.org/ng-lunar-lander-challenge/2008/teams/phoenicia
    2. http://www.teamphoenicia.org (it you guys could hit the donate button we could sure use it!)

  • Adam September 12, 2008, 17:30

    Hi Will

    Good thought. We get too used to thinking BIG and forget how to think big around here. A multi-asteroid mission is definitely a good option. Or how about a 10 MW SPS demo beaming a power beam at a probe? A Mag-Beam, laser, or ball bearings… whatever. So long as there’s in-space power/momentum transfer.

  • Adam September 12, 2008, 17:37

    Geoff Landis (again) has estimated that a multi-component SPS with 3 GW of in-space power masses just 1,300 tons (30,000 sub-components – L’Garde style inflatable concentrator solar collectors – massing 800 ton and 500 ton of structure.) That particular design doesn’t have a web of power-cables linking to a single rectenna – instead each collector is also a rectenna. So each sub-component masses 24 kg and collects 100 kW. Thus why I think 10 MW might be a reasonable goal for a power-beam demo.

  • Tibor September 12, 2008, 17:51


    “The probe must last 30 years.

    It must be autonomous.

    It must rendezvous with multiple bodies. Bonus money for different classes of bodies with the same probe.

    It must do a certain amount of science, not just take pix.”

    The Voyagers did all this actually – just put aside for a moment the discussion about the meaning of “autonomous”, which is not decisive here, I think.

    We must scale up a bit, I believe, for a real Mega X PRIZE.

    I reiterate some numbers from my earlier comment on interstellar sail missions:

    “Just a bit simple number crunching: 500 km/s = 105.4 AU / year (for comparison: Voyager 1 has a velocity about 3.6 AU/year) For a Centauri Mission (4.24 light years) this would mean 2.544 years cruising time, neglecting any acceleration and perhaps deceleration phases.

    What kind of reasonable things could such a “Long Bet 395” craft do during the long journey? Here a sort of milestones list:

    Year 1: LB 395 passes through the Kuipert belt and reaches the heliosheath about 100 AE
    Year 2: she leaves the heliosphere about 200 AE
    Year 6: she passes Sun’s gravitational focus about 550 AE
    Year 20 – 50: LB 395 now approaches the Oort Cloud (> 2.000 AE)
    All the time: gather tracking data for investigation of the Pioneer-Anomaly”
    Year 2000: Long Bet 395 reaches the Centauri System!

    The link to that comment is


  • Lubo September 13, 2008, 3:07

    Without the right technology, this mission is doomed since the begining. And I don’t see the X Prize gone far with conventional projects, or… manned voyages to the planets. Not to mention stars.

  • andy September 13, 2008, 9:18

    To be honest, I don’t see an interstellar mission happening before a more robust interplanetary infrastructure is developed in our own solar system. This would help drive improvement in propulsion technologies to a level where interstellar missions would be worth considering.

  • James M. Essig September 14, 2008, 14:12

    Hi Folks;

    This is a really interesting discussion!

    The idea of using the combined power output of 10 coil lasers as they are designed for the U.S. Airforce’s 747 YAL ABL aircraft might just do the job of providing enough laser power in a compact system to produce 100 MW of beam power in the IR frequency range.

    Assuming that the laser power is transferred to a 1 kg craft with an ultra-light solar sail with 50 percent efficiency including relativistic Doppler red shift based losses. In one year, the craft would acquire (31,000,000)(50,000,000) joules of KE. This equal 1.53 x 10 EXP 15 Joules. The craft would be traveling at about 0.2 C. Such a mission might be doable this century with arrival time occurring in the 21st Century. Miniature electo-dynamic slow down mechanisms could deposit the craft in either the Proxima Centauri System or Barnard’s star this very century if not during the first half of this Century. Assuming a cruising terminal velocity of the craft could be reached at 0.2 C within a year or even a few years, flight time to the Proxima Centauri system would be about 25 years and about 45 years to Barnard’s star.

    Obviously, the beam energy to ship based kinetic energy ratio would be very poor at first, but at say 0.2 C, the return would be much better using the equation KE = Integral (F dot ds) where ds is the position vector. I presume that the beam energy direction of incidence on the sail would be very close to parallel with that of the direction of craft acceleration and so the formula would obviously be approximated to Work = Delta KE = F dot d = (F)(d)cos theta. Simple and obvious math, and once the practical engineering is worked out, I see no reason why we could not have a fly by of our nearest stars or perhaps even a deposition of a small unmanned craft at any of our nearest stellar neighbors during the lifetimes of some of us if not a good number of us posting here at Tau Zero.

    I could not think of a better use for the high powered lasers and precise beam control systems being developed for defensive militaristic purposes than to apply such systems with improved beam accuracy and reduced beam divergence for pushing light sail craft to relativistic velocities.



  • Will Baird September 15, 2008, 15:04

    James Essig wrote:

    The idea of using the combined power output of 10 coil lasers as they are designed for the U.S. Airforce’s 747 YAL ABL aircraft might just do the job of providing enough laser power in a compact system to produce 100 MW of beam power in the IR frequency range.

    Jim, as an ex-HELSTF employee, the thought of the cost of the propellants is…staggering. We used DF instead of COIL based chemical lasers, but were briefed on the system. Your idea would be better served by using solid state lasers…and as they wear out, replacing them.

    Tibur wrote:

    “The Voyagers did all this actually – just put aside for a moment the discussion about the meaning of “autonomous”, which is not decisive here, I think.”

    So? And Redstone did the Anasari X Prize. The DC-X did the LLC. Lunokhod did the GLXP. The X Prizes with regard to space are retreads, less expensive retreads, but retreads all the same. An interstellar X Prize is expensive beyond comprehension for the next fifty years. Not to mention raising the money to grasp at it is just frankly beyond what a private group can probably do. I don’t mean the Prize money. That can, and has been, granted by the govvies. I mean the money to lob something at Alpha C…The GLXP Team Astrobotic is planning a $100 million budget…/and/ that’s /just/ to the Moon.

    Even the cost of putting 10 multibillion dollar COILs in orbit, keeping them fueled for 10 years or whatever, is simply well past what ANY set of companies can afford to sponsor…A government MIGHT be able to do that…MIGHT. You’d have to convince the people to support it and do it fast before they lose their focus. The electorate, it be fickle.

  • philw1776 September 16, 2008, 16:48

    OT: Let me interject that Will Baird has an EXCELLENT blog…


    Just ignore the occasional moonbat politics post :)

  • Will Baird September 18, 2008, 12:13

    Just ignore the occasional moonbat politics post :)


    Thanx for the endorsement though!