Comments (62)


    Thank you, Mr. Pete Klupar.

    Now, we have been challenging [....] over one from the thrust weight ratio : F/W > 1.0 with a new thrust force by the internal pressure difference of our unique propulsion evolution system (not open to the public).

    That means we (humankind) can reach ... over the Earch's atmosphere without the rocket fuel (of the burden on the environment) in case of successfully its testing (success of the above ground experiment).

    Probably, its test body may be able to go to the outer space with no rocket within this year 2017, (if the funds for... are raised)

    Our demonstration you requested will be showed sooner or later.


    Kingo Ueuchi
    AeroSpace Universe Corp.

  2. Breakthrough Initiatives:

    Apr 10, 2017 08:29 Posted on: Breakthrough Initiatives

    Thank you for the comments and for your interest in StarShot.

    - Avi Loeb, Breakthrough Starshot

  3. Theodore Frimet:

    Please feel free to delete this comment, as it is coming from the likes of a hobbyist, and not a dyed-in-the wool physicist.

    Allow the coherent light source to quantum tunnel, and emit as multiple wavelets on the opposing side of the "sail".
    Ideally, the emitted light waves, would be Minkowski photonic pressure, and pull the sail.

    No heat. No thermodynamics. Just photonic pressure.

    As for how to make the multiple waves, (and yes I can not do this) - laser stir a medium into a lowest energy state (Bose-Einstein Condensate), and separate parts of the condensate to produce the classic double slit.

    I can't hardly imagine how a physicist could use a Tunneling Electron Microscope (TEM) to move atoms; and how we could not move He in a similar fashion while existing as a BEC. Or a Josephson junction, to fire one electron at a time - but to make damn certain that the electron cascades into two virtual photons before entering the BEC medium.

    I know that a BEC can quantum tunnel. So, here's the charm and the fiction - (and why I've asked you to delete my comment if necessary) - photons striking the BEC don't have to quantum tunnel, if they can pass thru the double slit, do they? But if you could get a photon to tunnel (without the double slit) wouldn't it be exciting to find out that there are multiple waves, instead of one coherent beam?

    -Theodore Frimet

  4. Breakthrough Initiatives:

    Thank you for your comments. We will consider them as we build the system.

    - Pete Klupar, Breakthrough Starshot

  5. Breakthrough Initiatives:


    Thank you for your thoughts, Theodore. Your comments get at an extremely important aspect of the design of the lightsail, namely the microphysics of how the laser beam interacts with the material. The key considerations in selecting the sail material involve its
    - absorptivity (how quickly the sail heats up)
    - reflectivity (how efficiently the sail is propelled)
    - emissivity (how quickly the sail can cool)
    - density (how much the sail weighs which limits its terminal speed for a given energy supply)

    The best material in terms of these properties may well be a photonic crystal, in which the microscopic structure of the material is carefully arranged to exploit the quantum mechanical interaction between the material and the incident laser. This approach may also aid in improving the sail's stability on the beam. These issues were recently reviewed in a paper by Harry Atwater and his group at Caltech: and previously in a paper by Zac Manchester & Avi Loeb:
    We will be conducting a competition for good ideas some time in late 2019 for the next phase of this development

    - John Forbes and Avi Loeb (Harvard), Breakthrough Starshot


    Deflecting particles at the ship's fore compares in some ways with sails deflecting winds and sailing against them -- the angle is everything or you will not sail; you must generate lift with differential densities and such for gliding so I really do not believe lasers directed to the ship's fore will be of much use for travel -- I don't imagine sailing directly into a wind.
    With telescoped laser propelled sails at various angles to the ship might the ship might generate a bit of lift? I do not know really about J. T. Kare's idea exactly though.
    I believe that J. T. Kare has also suggested a mix of lasers and a magsail -- that is the thrust from a shockwave from a laser (fired toward the rear or at some angle -- the wave them travels in the reverse direction) might propel a magsail -- the return wave may have photons too so I would envision coating the magsail with titanium and maybe silicate and/or artificial diamond so there might be some propulsion from those photons. You need in any case a strong magnetic field around a ship to deflect protons so you will have some magnetic something (and that creates drag) so I envision using lasers to deflect some of that and then a reverberating wave from the laser providing some momentum with the magsail or shielding. (I have seen a toroid design with a good shield; you might add structure to the toroid's center as that too could be shielded with superconducting wires wound around the structure openings; the toroid needs its outer skin to have some insulation against neutrons -- maybe stored laser fuel.)
    -- C. E. Whitehead

  7. Breakthrough Initiatives :

    Dr. Whitehead,

    Thank you for your comment.

    You are right that Jordan Kare’s work on laser-driven microsails for interstellar propulsion does have a laser beam driving the sail. However his approach uses a “magnetic sail” or Magsail. That means that the sail has a superconducting hoop, which it uses for reflecting particles and therefore transferring momentum. However, Starshot is a much simpler concept. Starshot uses a laser to accelerate and has no deceleration mechanism. It does not have a Magsail, nor a superconducting hoop. Consequently, the issues raised in this question do not occur for Starshot.

    Jim Benford,
    Breakthrough Starshot Committee

  8. Dmitry Novoseltsev:

    Please consider supporting a small project to development a family of engines in the nearest future ( for Femto-class spacecrafts for pre-relativistic speeds using related technical solutions.
    Currently, work is underway to organize a profile startup D-Start:
    The proposed engines can be used for experimental development of certain elements of the Breakthrough Starshot technology, and in the "solar petard" engin version - also for experimental study of the movement of high-speed ultralight spacecrafts in the direction of the periphery of the Solar system and beyond.
    Additional information in the group
    All interested parties are kindly asked to contact the author:
    Questions about specific experiments are open for discussion and planning.
    Assistance in attracting investment or grants is welcome.

  9. Breakthrough Initiatives :

    Dear Dr. Novoseltesev,

    Thank you for you bringing this to our attention. Our team and Advisory Committee pays close attention to developments in propulsion and other technologies relevant to Starshot. While we are not currently at a stage to support the particular work you are doing, I will follow your project with great interest. Our next request for proposals will be for the Starshot Interstellar Communications Challenge which focusses on developing novel communications systems for a 1g spacecraft 4.2 LY from Earth. If this topic is of interest to you, please keep feel free to summit a proposal when the RFP is announced – likely in Q3 2020. 

    Very respectfully, 

    Pete Klupar
    Chief Engineer, Breakthrough Initiatives

  10. John Weiss:

    How about a sub-miniature version of some existing, validated drive technology, which hasn't been made in sub-miniature size before?

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