Re: Starshine-2 not seen again

From: Daniel Deak (dan.deak@sympatico.ca)
Date: Fri Jan 04 2002 - 01:14:12 EST

  • Next message: Bjorn Gimle: "Re: Starshine-2 not seen again"

    Jonathan T Wojack wrote:
    > 
    > Would I be correct in assuming that it is mathematically impossible to
    > make flash predictions for Starshine 2 and 3, like you can for the
    > Iridium constellation?
    
    Yes. 
    
    The mirrors on Starshine 2 cover about 60 % of its total surface compared to
    about 30 % for Starshine 3. Starshine 2's spin axis orientation, if there is
    one, is unknown. Starshine 3 is like rolling on its spin axis. This one was
    released sideways relative to the direction of motion of the rocket stage. But,
    angularly speaking, SS 3 has twice as many mirrors as SS 2.
    
    The surface of the aluminum skin is painted black for SS 3 and SS 2 retained its
    natural grey color. For detailed images of Starshine 2, see :
    http://www.obsat.com/star2ima.htm
    Visible magnitude for Starshine 2, based on observations of Starshine 1, should
    be around 8 or 9 in the absence of flashes. For Starshine 3, I will guess it
    should be lower given its color, even if it's twice as large.
    
    It has been studied to make Starshines look more like EGP but there were
    constraints on satellite size and how to impart such a high rotational speed
    without a costly spin system. Remember Starshine is a private project, having
    NASA as a major contributor, and there is a lack of resources to finance
    expensive new ways to make the satellite spin fast. If we were to use higher gas
    pressure on a tank inside the satellite, we would have to go through all the
    NASA safety reviews and tests for what they call "pressure vessels".
    
    Ideas are welcome on how to make the satellite spin faster while remaining
    visible from the ground, considering also the fact that students from all around
    the world polish mirrors for the sats (they must be small and simple to polish).
    Personally, I think we could achieve better visibility by putting more mirrors
    on the sats, increasing the spin rate and designing a more random pattern for
    the mirror positionning on the sat surface.
    
    Dan
    
    -- 
    Daniel Deak
    representant, projet spatial Starshine
    L'Avenir, Quebec
    
    COSPAR site 1747 : 45.7275N, 72.3526W, 191 m., UTC-5:00
    
    Site en francais sur les satellites:
    French-language satellite web site : http://www.obsat.com
    
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