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 : 45.7275°N, 72.3526°W, 191 m., UTC-5:00 Site en francais sur les satellites: French-language satellite web site : http://www.obsat.com ----------------------------------------------------------------- Unsubscribe from SeeSat-L by sending a message with 'unsubscribe' in the SUBJECT to SeeSat-L-request@lists.satellite.eu.org http://www.satellite.eu.org/seesat/seesatindex.html
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