LIGHT SAILS:

Discussion in 'Astronomy, Exobiology, & Cosmology' started by paddoboy, Jan 26, 2015.

  1. paddoboy Valued Senior Member

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    Planetary Society announces test flight for LightSail
    by Staff WritersPasadena, CA (SPX) Jan 26, 2015:

    The Planetary Society today announced the first of its LightSail spacecraft will embark on a May 2015 test flight. Funded entirely by private citizens, the solar sail satellite will hitch a ride to space aboard an Atlas V rocket from Cape Canaveral Air Force Station in Florida.

    The mission will test LightSail's critical functions, a precursor to a second mission slated for 2016. That second flight will mark the first controlled, Earth-orbit solar sail flight and ride along with the first operational launch of SpaceX's Falcon Heavy rocket.

    "There's an old saying in aerospace, 'One test is worth a thousand expert opinions.' After six years of development, we're ready at last to see how LightSail flies," said Bill Nye (The Science Guy), CEO at The Planetary Society.

    "LightSail is technically wonderful, but it's also wonderfully romantic. We'll sail on sunbeams," added Nye. "But wait, there's more: this unique, remarkable spacecraft is funded entirely by private citizens, people who think spaceflight is cool."

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    After the sails unfurl, LightSail will test its attitude control system and study the behavior of the sails for a few days before it is pulled back into the planet's atmosphere. Key images and data on the spacecraft's performance will be sent to ground stations at Cal Poly San Luis Obispo and Georgia Tech.





    More at......
    http://www.spacedaily.com/reports/Planetary_Society_announces_test_flight_for_LightSail_999.html
     
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  3. cosmictraveler Be kind to yourself always. Valued Senior Member

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    What good is this device if it is slow can't hail much and needs sunlight to work?
     
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  5. paddoboy Valued Senior Member

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    Advantages:
    [1] No propulsion fuel needed.[lower launch mass]
    [2] Cost saving:
    [3] Continuous thrust and acceleration:
    [4] Unlimited and constant flow of photons:

    Disadvantages:
    [1] Very large area needed to facilitate acceleration:
    [2] Probably of a very delicate material:
     
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  7. cosmictraveler Be kind to yourself always. Valued Senior Member

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    Two trials of spacecraft have successfully unfurled their solar sails, and demonstrated that radiation from sunlight can power them through interplanetary space.

    Solar sails use photons from the Sun to propel spacecraft at high speeds. On 20 January, the small lightweight spacecraft NanoSail-D deployed a 10-square-metre gleaming sail in low-Earth orbit.

    Shortly after, on 26 January, engineers at the Japan Aerospace Exploration Agency (JAXA) announced the extension of their solar-sail mission IKAROS. Launched in May 2010, IKAROS flew past Venus in December last year, and the mission will continue until March 2012.


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  8. theorist-constant12345 Banned Banned

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    Wow! I had this idea several years ago as seen in free thought thread before the announcement.

    I noticed a comment about the speed of the device/spaceship, I understand that Newton's Laws's of motion may come into the process. Space will have no friction on the device/spaceship and has soon as the device as left the gravitational strengths, the acting external forces will be removed or lessened to a degree that there will be nothing stopping the device/spaceship in accelerating to greater speeds.
    The device/spaceship should according to the Law's of Physicals reach a speed equal to the speed of the force continued flow.

    Had to comment on this sorry.
     
  9. cosmictraveler Be kind to yourself always. Valued Senior Member

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    How do you stop it or turn it?
     
  10. theorist-constant12345 Banned Banned

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    That is simple mechanics, the complete device will be black with the exception of one side/rear being perpendicular to the light source. A rear that can flip side, so when we want to stop the acceleration we flip side the rear. Newtons Laws of motion will allow the device/spaceship to continue momentum even when the force is removed, we then can flip side the front of the device/spaceship, or sides of the device/spaceship, to become perpendicular to a different star that will be a force equal and opposite to the direction of the device/spaceship , changing velocity .
     
  11. cosmictraveler Be kind to yourself always. Valued Senior Member

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    What is going to make it "flip"? Even if you turned the sail to the black side it won't stop because it will just keep on traveling at the same speed that it established .
     
  12. theorist-constant12345 Banned Banned

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    It does not have to be a flip, it could be has simple as a shutter that closes or opens. I understand it will not stop by Newtons second law unless being acting upon by external forces. That is why the whole device/spaceship would have shutters all around the device/spaceship for velocity change, close the rear shutter and open the forward shutter and the light you were using to propel will cease in force, and the opposing force of light from destination will slow the device/spaceship down.
    My apologies to the mods, I am not making a speculation, I am referring to Newtons laws of motion and the Physical process involved in a light propelled device/spaceship.
     
  13. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

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    That doesn't happen.
     
  14. theorist-constant12345 Banned Banned

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    Then Newtons second law can not apply and is null and void?
     
  15. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

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    What?
    It implies nothing of the sort.
     
  16. theorist-constant12345 Banned Banned

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    Should the Law not state - That an object in gravitational motion will remain in gravitational motion unless acted upon by an external gravitational force or an external applied force?

    P.s The light sail will fail because there is no gas like in the Crookes device. The sail will work by the solar winds.
     
  17. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

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    No.

    No and no.
     
  18. theorist-constant12345 Banned Banned

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    Can I honestly ask why? in the universe there is no place that external forces are not acting, so to say a law that states a body will remain in motion unless acted upon by external forces does not make any sense to me when there is apparently no such place?

    In theory if there was such a place then yes I agree with it, but as the circumstances are, the statement I asked about makes valid sense of the present truth so far?
     
    Last edited: Jan 27, 2015
  19. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

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    So what?
    BECAUSE those forces are acting THEN it's possible to work out what motion is induced.
     
  20. theorist-constant12345 Banned Banned

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    So what?

    I do not want to go off topic, but forces of light etc is the forces involved when talking about a light sail.

    ''BECAUSE those forces are acting THEN it's possible to work out what motion is induced.''

    Word salad I can not understand, can you reword it please?
     
  21. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

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    Newton's Law is a generalised case that is applicable to ALL situations.
    Your "version" is more specific and thus less useful.

    Gravity comes under the heading of "external force" and thus is included/ catered for by Newton.
     
  22. theorist-constant12345 Banned Banned

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    Your answer seems contradictory can you explain please.

    ''Gravity comes under the heading of "external force" and thus is included/ catered for by Newton.''

    If gravity is an external force, and an object will remain in motion unless acting upon by an external force, why does gravity, the external force not stop the Earth's motion according to the law?

    How can the light sail escape gravity with a weak force applied?

    Would the earth or the Sun just not use the external acting force to pull it back?
     
  23. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

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    That would be because you don't know what you're talking about.

    Where do you get "stop" from?
    BECAUSE of gravity the Earth is in orbit round the Sun.
    If there were no gravity Earth would continue in a "straight line".

    For some one that has persistently quoted "F=ma" you appear to to have not understood it.

    Oh boy...
    Have you calculated the relative forces involved?
    (My bad, you're mathematically clueless too, aren't you?)
     

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