I think people are reading far too much into the "disappearing trick". The brightness changes are much more likely than anything to be the result of what Bjorn describes. Would it be worth the mass penalty of a mechanical cloaking system and what is the point? What would be the project Risk Manager's view of the additional hardware, mechanics and electronics when weighed against the operational mission? Lacrosse is a very expensive and not-easily-replaced piece of hardware to lose because an unnecessary bearing seizes up at an inopportune moment. Active cloaking devices are for experimentation, Dracula, and Romulan Warbirds. Bob Christy > -----Original Message----- > From: John Locker [mailto:john@satcom.freeserve.co.uk] > Sent: Thursday, January 10, 2008 9:38 PM > To: SeeSat-L@satobs.org > Subject: Re: Light Curve from Satellite Trail > > I agree to some extent Björn , especially in the case of structures > like ISS where we see obvious shadowing from the large solar > arrays....but that shadowing is only noticed when we look at images > taken at high magnification.From the ground the naked eye observer > wouldnt really be aware . > > L5 and possibly 3 and 4 seem to have a more "on / off" > ability to change brightness. > > In some reports it is muted that MISTY used some sort of inflatable > device to cloak itself....I think that highly unlikely....but rather > it used a simply mechanical system and so too Lacrosse . Perhaps > light absorbing , non reflective panels which encase the outer > structure when required. Of course if that was the case , why not > leave the panels in situ all the time to stop the satellite reflecting > at all. > > All very confusing. > > As an aside , I imaged Lacrosse 2 this evening during a 64 degree pass > , no flaring or disappearing trick was observed. > > John > > ----- Original Message ----- > From: "Björn Gimle @GlocalNet" <bg_26934@glocalnet.net> > To: <SeeSat-L@satobs.org> > Sent: Thursday, January 10, 2008 6:41 PM > Subject: Re: Light Curve from Satellite Trail > > > > Without knowing the exact layout, IMHO any satellite with a large > > antenna/panel monted on some boom outside the spacecraft can get > > into an attitude where we see the dark backside of the panel, and/or > > the panel shadows the satellite. > > > > Likewise, more or less box-shaped satellites can in some attitudes > > display only shadowed surfaces to the observers, and there may be no > > large protrusions that cast even secondary light onto these > > surfaces. > > > > Just my 5c > > > > /Björn > > > > ----- Original Message ----- > > From: "John Locker" <john@satcom.freeserve.co.uk> > > To: <SeeSat-L@satobs.org> > > Sent: Thursday, January 10, 2008 6:05 PM > > Subject: Re: Light Curve from Satellite Trail > > > > > >> On that page , Phil says... > >> > >> > >> "A sudden brightening, then a drop of 5 magnitudes then a > final flare." > >> > >> Which is more or less how I observed L 5 when I took a > series of images > >> at the end of last May > >> > >> http://mysite.wanadoo-members.co.uk/satcom_transits/Lstrip.jpg > >> > >> The flare as it returned was quite distinct , before it faded again > >> > >> To me this says one of two things...either L5 rotates to > make itself > >> "invisible" ...or it has a mechanical device that shields it. > >> Question is , why only go into stealth mode for short periods ? > >> > >> John > > > -------------------------------------------------------------- > ----------- > Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L > archive: > http://www.satobs.org/seesat/seesatindex.html > > > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.5.516 / Virus Database: 269.19.0/1216 - Release > Date: 09/01/2008 10:16 > > > No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.19.0/1218 - Release Date: 10/01/2008 13:32 ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
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