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Breakthrough Starshot: ‘Challenges’ Forum Opens

Ever since coming back from the Breakthrough Discuss meeting in Palo Alto, I have been pondering the enormous issues the Breakthrough Starshot project will encounter. Getting a tiny spacecraft up to twenty percent of lightspeed is only the beginning of an effort that has to deal with power generation, a phased laser array of enormous strength and complexity, the miniaturization of critical components, lightsail integrity under thrust and much more.

These topics were freely discussed in Palo Alto, and especially at the Yuri’s Night party that Yuri Milner threw for the assembled conference goers. When I talked to Milner at the party, he suggested an idea that we have been working on ever since. In order to keep the discussion on the critical issues involving Breakthrough Starshot in front of the interstellar community, why not set up a linkage between the discussion areas of the Breakthrough site and Centauri Dreams? This site would maintain its usual structure and separate comments, but it would then include a section specifically devoted to pursuing the Breakthrough Starshot concept.

I am the world’s poorest programmer, but a crack team from Breakthrough Initiatives, led by Stepan Torchyan and including Peter Petrov and Konstantin Efimov knew exactly what to do. As of this morning, the new section goes live. You’ll find the ‘Challenges’ forum accesible through the ‘Breakthrough Starshot’ tab at the top of the Centauri Dreams logo, Click on ‘Breakthrough Starshot’ and you’ll see it is set up as a series of forums, each of them dealing with a single major issue for the project. A ‘Challenges’ link also appears on the Breakthrough Initiatives site.

What’s happening here is that any comments Centauri Dreams readers place in one of these forums will be mirrored on the Breakthrough Initiatives site, while comments posted there will appear on the ‘Challenges’ forum pages on this site. As long-time readers know, Centauri Dreams doesn’t require a login in order to post, but ‘Challenges’ does. You can set up a password on the ‘Challenges’ page. Click the ‘Breakthrough Starshot’ tab, then click ‘Sign In’ and, on the ensuing page, ‘Sign Up.’


When you go to the new forum, you’ll see that the list of topics is lengthy, and I hope that we can continue the many good discussions we’ve already had on Centauri Dreams in this new venue, even as we follow the project with articles and comments on Centauri Dreams itself. Many of the current topics came under discussion in Palo Alto, but as Breakthrough Starshot begins its work this summer, each will come into sharper focus.

Simply put, there could be a deal-breaker almost anywhere on the list of Challenges. If we build the phased laser array to boost a Starchip up to a substantial percentage of c, would the sail be stable under the beam? Would the phased array work as we hope through the atmosphere? What about objects in the beam’s path — a bird, an airplane? What of the collision potential for a spacecraft moving at these velocities in cruise, and how do we manage to adjust the spacecraft’s course on the way? And a huge one: How do we manage data return considering the minute size of the Starchip we hope to send to Alpha Centauri?

Have a look at the Challenges forum as we begin to see how it will work. Stepan Torchyan’s team will check into any bug reports if problems arise, and after an initial shakedown, we should be able to add to the Breakthrough Starshot discussion daily. I’m happy to be able to bring these forums to the attention of the Centauri Dreams audience considering how much I’ve learned from readers here since I began the site in 2004. I have no doubt we’ll be able to make a contribution to this ongoing study to achieve what I’ve always dreamed about, a human technology arriving intact and returning data from the Alpha Centauri system.


Comments on this entry are closed.

  • Robert May 25, 2016, 12:34

    Is there really anything these nano probes could achieve that won’t eventually be achievable with advanced higher resolution instruments based in our own solar system along with a good measure of human ingenuity?

    • Robert May 27, 2016, 14:41

      As I figured, no one here is even interested in that possibility.

      • Micky Badgero May 27, 2016, 20:57

        Robert, the Breakthrough Starshot seems to depend on advanced imaging, such as from the gravitational focal point of the sun. The is not lack of interest, the problem seems to be that no one knows the answer to your question.

    • Mark Zambelli May 28, 2016, 4:46

      For imaging… probably not, but measurements of zodiacal dust, magnetic fields, plasma science etc can only be performed in-situ. And we get to actually go there with, as Paul mentioned, human technology. Then there is the notion that this mission is a precursor to bigger and better things leading eventually to human/transhuman flights out into the cosmos… and that’ll never happen if all we do is make our homebased telescopes bigger and better.
      To me, this mission is more for the actual going there, rather than data aquisition of the AC-system, which frankly, and until further notice, may not even have planets.

  • Giulio Prisco May 25, 2016, 12:38

    Great initiative Paul! I successfully logged in with the same login and password that I had created at the Breakthrough Initiatives site.

  • don wilkins May 25, 2016, 12:44

    I tried to sign-in but each time was notified that my actions were unsuccessful. I’m pretty sure I correctly identified the pancakes but may have shanked the ball on pickups :)

    I briefly looked over the sections of the challenge. Very exciting. Why is there not a section on communications?

    • Paul Gilster May 25, 2016, 14:05

      Still working on the forum. The programming team will see all these comments, and we’ll get this fixed. Sorry for the trouble! Let me know if this persists.

    • Micky Badgero June 2, 2016, 9:09

      There are three sections on communications:

      Communication | Pointing transmitter towards earth
      Communication | Sending images with laser using sail as antenna
      Communication | Receiving images with light beamer array

      Or did you mean a section on contacting the web admin?

  • Micky Badgero May 25, 2016, 12:59

    Thank-you Paul.

    Are there any experimenters out there? I think the Breakthrough Starshot is a very interesting concept. Much of it is beyond my ability to test. What I am looking at is the following:

    I started with the idea of a millicubesat, a one centimeter cube, with one-square-centimeter solar cells on all sides, and with a camera and a laser transmitter, just to see if I could get it down to one gram. Nothing is built yet, but this quickly evolved to a two-centimeter long prism shape with one-centimeter-width sides, and two solar cells on each side. Hollow in the middle to simulate a low cross-section for a real Starchip. The camera is on the inside, and the triangular shape seems necessary to give the lens a reasonable focal length.

    Cameras are easy to get. Lasers are easy to get. Small image processors are easy to get. The problem is that high-efficiency solar cells are not easy to get. The only high-efficiency, one centimeter-square cells I know of are concentrator cells. Three companies make these, but they only sell thousands of dollars worth at a time. Does anyone know of a source for these in small quantity? (25 or less?)

  • Michael May 25, 2016, 13:18

    Unfortunately I got the password wrong and got locked out, I sent an e-mail to the site to reset it but still no reply :(

    • Micky Badgero May 25, 2016, 14:03

      Good luck with that. I’ve been locked out for a month.

      • Micky Badgero May 25, 2016, 14:19

        Forget this. I tried to reset my password a couple times in the past month and it failed. I reset my password today and it worked.

    • Paul Gilster May 25, 2016, 14:06

      Keep me posted, Michael. We’ll get you back in. The Breakthrough team is tracking the rollout of this closely.

      • Michael May 26, 2016, 4:15

        Thanks Paul, password reset and can log in.

      • Michael May 26, 2016, 8:40

        I have added some ideas, half-baked of course.

    • Paul Gilster May 25, 2016, 14:45

      Be sure the answer didn’t go into your spam folder, Michael. This has happened a few times already. If that’s not the answer, we’ll find out what is.

  • Giulio Prisco May 25, 2016, 13:23

    I suggest to rename the “Challenges” tab “Starshot Challenges” (or just “Starshot” if that’s too long for the theme layout), otherwise it’s not evident what the tab is about.

    • Paul Gilster May 25, 2016, 15:01

      Good idea, and the change has already been made.

  • Giulio Prisco May 25, 2016, 13:28

    Clicking on a thread displays the posts starting with the last page instead of the first. Is that a bug or a feature?

    • Micky Badgero May 25, 2016, 14:04

      Feature. They have always been like that.

    • Paul Gilster May 25, 2016, 14:06

      It’s the format I prefer but we’ll see how reaction goes.

      • Kamal Ali May 25, 2016, 23:12

        I also prefer starting on first pg.

  • CharlesJQuarra May 25, 2016, 15:10

    I think the constraint that Milner is imposing on the design requirements is too severe: a laser grounded on earth’s surface limits unnecessarily the kind of wavelengths that can be used for the lasers to those that have minimal atmospheric absorption, i.e. microwaves.

    In any case, these are very exciting news

  • Matt May 25, 2016, 16:18

    I was able to log in with the username and password I created on the Breakthrough Starshot site. Unfortunately these are still insecure http web sites. I hope they can at least make them https.

    This great, I am happy to see Centauri Dreams involved. All very exciting.

    • Paul Gilster May 25, 2016, 16:53

      Good point, Matt. Useful pointers like this will help shape the forums and their development.

  • John Walker May 25, 2016, 16:29

    Brilliant! I just want to say thank you and congratulations. Whilst not competent to contribute myself, I am immensely keen to keep abreast of the developments. May the quality and quantity of contributions be reflective of the fantastic scale of this inspiring initiative.

  • Project Studio May 25, 2016, 20:55

    That’s just what I was thinking (the forum at Breakthrough is a bit cumbersome and doesn’t have features such as ‘reply’ that the CD forums have).

    Getting log in errors:
    1. The Breakthrough site, as well as the Breakthrough forum on Centauri Dreams, do not accept the Australian domain “.com.au” sufix.
    2. Using an alternative “.com” email I was able to create an account at Breakthrough site many weeks ago, but trying to use that account to sign into the new CD Breakthrough forum now I get a 403 error.

    • Paul Gilster May 26, 2016, 9:11

      Thanks for this. The forum team will see your report and, I hope, get this fixed.

  • JeFF May 26, 2016, 2:05

    Another question for the forum, but I’m not sure how to phrase properly:

    at 0.2C speed, each probe will have tremendous cinetic energy. And we will not be able to direct them very precisely.
    So, as seen from afar, the Initiative could look more like a massive bombin than a science mission.

    What do you think ?

    • Michael May 26, 2016, 10:49

      The transverse energy requirement is much less than the axial requirement so a fair distance can be managed over time.

      • Ivan May 26, 2016, 20:15

        I’m reading the “Three Body Problem” at the moment and the REAL reason behind Project Star Shot just occurred to me….

        Its the launch system for a barrage of guided interceptors to be fired at the Trisolarian fleet!!! :-)

    • Andrew Higgins May 29, 2016, 12:10

      As Geoff Landis puts it, *any* interstellar flight capability will also look like a megadeath weapon. This is simply a consequence of the energy required for interstellar flight. There is no way to avoid it.

  • Michael May 26, 2016, 13:31

    Paul how often is it updated as I added some ideas but they are not on the site through the CD Web link but they are on the main site?


    • Paul Gilster May 26, 2016, 15:59

      Michael, there should be no gap. The comment should have gone straight through from here. I’m surprised to hear that it appears on the Breakthrough site but not through the forum as presented here. I’ll pass this along.

  • Robert May 30, 2016, 14:29

    I’m currently 62 years old. In the opinion of folks here, can I reasonable expect to be alive when the first data from this project comes back?

    • Mark Zambelli May 31, 2016, 12:15

      Hello Robert, I’m 44. As far as I know, and please anybody correct me if I’m off track, may I offer you my take?

      If I may clarify something about this project… the $100milion being spent on this is to perform a feasibility study, of sorts, on overcoming the numerous hurdles, none of which seem to be game-ending, in getting a mission like this off the design sheets and actually going. It’s the first massively funded study (as far as I can tell) of its kind… Yuri’s donation dwarfs any government spending in this area…ever.

      It would require several billions to actually fly something like this. I’m not too sure when this precursor-project is likely to submit it’s conclusions but a bona-fide mission would only start after this.

      Any data return dates would be set once the main Starshot mission gets funded and is underway. Flight times at 0.2c would be around 20 to 25yrs to get to AC.

      • Mark Zambelli May 31, 2016, 14:00

        Ok, if you are after data coming ‘out’ of this study then according to Dr Benford ( https://youtu.be/MD0KFBc3AL8 ) it may be 10 years or so. If you are referring to data coming ‘back’ then add on a further 10 yrs (plus oodles of instantly found funds), plus the 20-and-a-bit yrs flight time… plus 4.something yrs data travel time back home.
        Roughly 50 yrs.

        • ljk June 1, 2016, 17:50

          That is faster than the BIS Daedalus probe which would have taken 50 years just to get to Barnard’s Star. Or 38 years to Alpha Centauri once you discover that the exoplanet data on the former was in error. :^)

    • ljk June 1, 2016, 17:51

      If you exercise and eat right.

    • Giulio Prisco June 2, 2016, 11:50

      Hi Robert. I am four years younger than you. No, unfortunately we can’t reasonably expect to be alive when the first data from the project comes back. Perhaps, but just perhaps, we will be able to see the launch. Unlikely, but we can hope.

      But does it matter? We are part of it. We are part of the wonderful cosmic adventures of future generation, and the little things that we can do matter.

  • ljk June 1, 2016, 17:53

    Q&A: Web billionaire describes his plan to shoot for the stars

    By Zeeya Merali

    May. 26, 2016 , 6:00 AM

    Last month, Russian internet billionaire Yuri Milner announced plans to send thousands of tiny spacecraft to visit Alpha Centauri, the closest star system at 4.4 light-years from Earth. Dubbed Breakthrough Starshot, the mission aims to take close-up images and collect data from any potentially habitable planets there. In order to cover the vast distance—41 trillion kilometers—in a reasonable time, the proposed spacecraft will each weigh less than a gram. Once in space, they will unfurl lightweight sails to catch laser beams shot from Earth, accelerating to one-fifth the speed of light under light pressure. Launch could be 30 years off, and the trip to Alpha Centauri would take a further 2 decades.

    Milner, who also supports the multimillion-dollar Breakthrough Prizes and Breakthrough Listen, a search for signs of extraterrestrial intelligence, has committed $100 million to this venture. But Breakthrough Starshot has polarized opinion: Some are enthused by its ambition, whereas others say it is costly and unnecessary, isn’t feasible, or is downright dangerous. Milner spoke with Science by phone about the challenges facing the project and how he answers his critics. His responses have been edited for clarity and brevity.

    The interview is here:


  • Micky Badgero June 1, 2016, 22:08

    Hi Paul,

    Breakthrough Starshot Challenges are old data, maybe coming from some server cache. Definitely older data than from the Breakthrough Starshot web site.

    Best regards,

    Micky Badgero

    • Paul Gilster June 2, 2016, 9:12

      Thanks, Micky. I’ll make sure the programming team is aware of this.

    • Paul Gilster June 2, 2016, 20:15

      Micky, the programming team checked into this and it turns out there was indeed a cache problem. Should be resolved quickly. Many thanks.

  • ljk June 2, 2016, 17:58

    These Tiny Spacecraft Could Lead Us to Alpha Centauri

    Maddie Stone

    June 1, 2016 at 5:05pm

    Full article and video here:


    To quote:

    Meet Sprites: sticky note-sized devices that sure look like the result of the Pentagon’s long-anticipated floppy disk purge, but are in fact state-of-the-art spacecraft complete with solar cells, a radio transceiver, and a tiny computer. Later this summer, a Cornell-led project called Kicksat-2 will launch 100 of these puppies to the International Space Station. There, the satellites will spend a few days field-testing their navigational hardware and communications systems before burning up in orbit.

    The project’s lead engineers, Zachary Manchester and Mason Peck, are on the advisory committee for Breakthrough Starshot, an ambitious effort to reach our nearest neighboring star system within a generation. (In fact, the potato chip-sized computer Milner held up during a highly publicized press conference in April was Manchester’s own design.) Sprites, and the “chipsat” technology they’re based on, are a step toward that goal of interstellar travel. More generally, they’re an indication of the future of space exploration.

    “A chipsat is never going to replace a big [spacecraft], but it can do exciting new things like land on a planet,” said Brett Streetman, an aerospace engineer with the Cambridge-based nonprofit Draper, which has been developing chipsat technology since 2010. “We imagine sending them to places where you wouldn’t want to risk sending your normal spacecraft, or leveraging the physics of getting that small.”

    • Micky Badgero June 3, 2016, 17:46

      Interesting project. They do not appear to have any sensors. Also, the solar cells shown on these were discontinued quite a while ago, so this will be a bit of a one-trick pony.

  • ljk August 17, 2016, 12:39

    How Starshot will get us to Alpha Centauri in 20 years

    by Colm Gorey

    August 16, 2016

    Travelling into the darkest depths of the universe could soon be as easy as flicking on a switch, or at least a switch for a giant laser system that will fire a spacecraft at 150m kmph [???] to Alpha Centauri.

    Back in April 2016, the philanthropic research group Breakthrough Initiatives announced it was putting millions of dollars into developing a spacecraft capable of reaching Alpha Centauri in the next 20 years. [Or maybe Proxima Centauri now.]

    This would be some claim given that, despite it being our nearest neighbouring star, it’s located more than four light years away.

    Full article here:


    To quote:

    Where else would such monumental first steps to bring this potentially revolutionary space technology to the world begin other than on a goat farm.

    “In December 2015, I got a phone call when I was actually away from Harvard [University] visiting Israel with my wife and she said, ‘Why don’t we go to a goat farm for the weekend?’,” recalled Prof Avi Loeb, renowned theoretical physicist and chairperson of the Breakthrough Starshot Advisory Committee, who is one of the scientific leaders of this incredible technology.

    Not long after they arrived, Loeb got a call from Breakthrough Starshot’s executive director, Pete Warden, asking him to file a report on the initial findings of whether such a project was feasible.

    “I said okay, but at the goat farm there was only internet in the office and I sat with my back to the wall at 6am in the morning looking at the goats and making up this presentation that I later delivered,” he said with incredulity.

    “It was bit surrealistic to look at the goats, and I bet the owner of the goat farm never imagined that the first realistic plan to go interstellar was contemplated at that farm!” [Historians take note!]


    “The cost of an iPhone is nothing [in terms of space travel], so if one of these things burns, who cares? It’s not much money and you didn’t risk human life. This was not feasible more than a decade ago,” Loeb said. [Let’s just hope it isn’t aware, ay?]


    There is also the issue of keeping a human crew populated for decades and, as Loeb points out with a dash of humour: “How many times can you watch a movie?” [And this is why I do not want a theoretical physicist planning any manned interstellar missions.]


    But before Breakthrough Initiatives can begin its mission to Alpha Centauri, Loeb agreed that, in the meantime, the solar system offers a much more achievable testbed.

    If it can travel over four light years in 20 years, surely a flight to Jupiter, Neptune or even Pluto would take a fraction of the time it currently takes?

    “I actually think that a search within the solar system would be an intermediate step and this could revolutionise [near-Earth] studies,” Loeb said.

    and finally…

    Concluding on a high note, Loeb said that this scattergun approach of launching thousands of craft in the universe will ultimately offer us the best chance of finding intelligent life out there in the universe.

    Not due to the chances of one of the craft picking up a signal or evidence of extraterrestrials, but rather that something in the vastness of space would have a much better chance of finding us.

    “I think if we just wait a few centuries, our civilisation would send so many devices into space that [Earth’s] biggest [celestial] signature would be those devices.”

    Let’s hope someone, or something, out there is listening.

    [It is ironically amusing to see how while some (many) folks are quite fearful of us alerting an ETI to Earth and humanity’s presence, guys like Loeb and the author of this article think it would be just dandy. Perhaps similar differing points of view have and are taking place on other inhabited worlds as well. In any case I have brought up in CD and elsewhere more than once that every probe we send into the wider Milky Way galaxy will be our ambassadors into the unknown. Therefore they all need to carry some kind of information package to let any recipients know their (non-hostile) purpose and who sent them, along with when if at all possible. A lot of information can be stored in a small space these days and made relatively easily readable. If we are smart and bold enough to seriously consider interstellar missions, we need to be thinking ahead in all aspects of such a venture as much as possible. Merely lobbing vessels (and their final rocket stages) into deep space without any serious thought about what might become of them and how they could affect any recipients is frankly irresponsible. We can no longer ignore the issue as NASA largely did back in the early days, requiring Carl Sagan and just a few others to step in to fill that gap.]

  • ljk August 22, 2016, 13:27

    Do cubesats make good training devices for Breakthrough Starshot?