[Laser] Laser retroreflectors on Sats

[Garnier Yves]

Hi all
Iridium sats are not only able to reflect the sun but also the city lights.
http://sd-1.archive-host.com/membres/up/22679775843705539/PGPVUK.pdf
As suggest Tim, the larger the light source area the longeur the bounced signal duration. 
Yves F1AVY
http://f1avyopto.wifeo.com

--- En date de : Mar 1.9.09, James Whitfield <n5gui at cox.net> a écrit :

> De: James Whitfield <n5gui at cox.net>
> Objet: Re: [Laser] Laser retroreflectors on Sats
> À: "Free Space LASER Communications" <laser at mailman.qth.net>
> Date: Mardi 1 Septembre 2009, 5h40
> Tom
> 
> According to the Wikipedia article on satellite flares, the
> Iridium flare 
> comes from "one of the three door sized highly polished
> antennas" on each 
> satellite, not from its solar collectors.  I beleive
> it also says something 
> to the effect that one of the antennas is oriented to face
> the direction of 
> travel, so it, and presumably the other two, rotates in
> inertial space as it 
> goes through its orbit.  I am going from memory as I
> don't want to pull up 
> the article again this late at night, but I think the
> inclination of the 
> orbits are such that each changes the orientation of its
> plane as well.
> 
> I hope that might answer your question.  Not that it
> would make the task of 
> trying to hit one with a light beam at a time when you
> could predict a 
> useable reflection angle.
> 
> James
>  n5gui
> 
> 
> ----- Original Message ----- 
> From: "Tom Becker" <GTBecker at RighTime.com>
> To: "Free Space LASER Communications" <laser at mailman.qth.net>
> Sent: Monday, August 31, 2009 9:11 PM
> Subject: Re: [Laser] Laser retroreflectors on Sats
> 
> 
> > > ... Instead of the nice long 10 or 15 second
> brightening due to the
> > sun having a half degree source size, lasers -being
> point sources-
> > would have a much shorter length of maybe only a few
> milliseconds (a
> > guess) not to mention a much smaller area over which
> they could be seen.
> >
> > But isn't the geometry simply wrong?  Iridium
> birds are stabilized to
> > keep solar panels perpendicular to the Sun, aren't
> they?  If that is so,
> > I don't believe there is any Iridium orbit position
> where the
> > mirror-like panels - in which we see the Sun's
> reflection during an
> > Iridium flare - will reflect an Earth-borne source
> back to the Earth.
> > Is that wrong?
> >
> > Tom
> >
> >
> >
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