Communication | Pointing transmitter towards earth

Finding the Earth should be reasonably straightforward, given its proximity to the Sun, which would be bright from the vantage of Alpha Centauri. The on-board star tracker would also be useful, as would locking onto the Starshot laser system.

It may also be feasible to send commands and even reprogram the entire nanocraft via the Earth-based laser system. The angular diameter of a diffraction-limited beam, at a wavelength of 1 micron with a meter-class antenna, is on the order of 0.1 arcseconds. Pointing to this precision could be achieved by using the photon thrusters.

Comments (26)

  1. Aakash Rao:

    Hi, I am a student and not much of an expert but could we place something like a gyro, which always point towards the earth so that we could send signals later

  2. michael.million@sky.com:

    I think every now and then the laser should be fired so that at least some laser light could be used to allow the probe to correct its trajectory and allow better pointing towards Earth.

  3. John Gates:

    When the probes are 4.3 years out from PC fire up the laser used to propel them and send a beam at the collection of probes. As the probes reach PC they open up a set of retro-reflectors which can be modulated with far less power than an on-board transmitter would use. The beam from the laser array would arrive at the time of reflector opening and, then being modulated, would inherently send the data directly back toward Sol.

    Just a thought.

  4. Breakthrough Initiatives:

    RE:
    Feb 23, 2017 07:12 Aakash Rao Posted on: Breakthrough Initiatives

    Answer:
    Thanks for your question. We think that gyro would weigh to much to be carried on the star ship. We need to use and reuse everything many things. Our current thoughts are to use the camera onboard to look for the sun and other bright stars to be able to find our locations.

    - Pete Klupar, Breakthrough Starshot

  5. Breakthrough Initiatives:

    RE:
    Mar 12, 2017 10:39 michael.million@sky.com Posted on: Centauri Dreams

    Answer:
    Thanks for your input. This is a very good idea. We will use it

    - Pete Klupar, Breakthrough Starshot

  6. Breakthrough Initiatives:

    RE:
    Mar 13, 2017 19:50 John Gates Posted on: Breakthrough Initiatives

    Answer:
    Thanks for your input. This is indeed a good idea. We need to find retroreflectors that are light enough to meet our mass budget

    - Pete Klupar, Breakthrough Starshot

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