[amsat-bb] Re: sirius orbit name?

Mark Lockwood mark at kk7cu.net
Fri Feb 22 01:48:11 PST 2008

My employer used to operate the 3 Sirius Radio Satellites for them.  They
are highly inclined Geosynchronous, and are set so at least one of the 3 is
always over North America.  The idea is to have a higher look angle for most
of their customers, reducing dropouts from obstructions.  The Kep data for
the 3 of them as well as XM radio's birds is available from Celestrack at
http://www.celestrak.com/NORAD/elements/other-comm.txt .

The 3 Sirius birds currently in orbit are Space Systems Loral FS 1300 Series
birds modified so they can be flown inclined.

73 DE Mark KK7CU

On 2/22/08, Alan Sieg WB5RMG <wb5rmg at somenet.net> wrote:
> >> The Sirius birds are in an "Inclined Orbit".
> > Is this type of orbit can be a solution for the next HEO?
> The reference to the Molniya orbit could be to recall the orbit of
> AO-13...     slow high-altitude lingering Northern Hemisphere apogees,
> rotating ascending nodes about the globe to distribute coverage more
> evenly around the globe. Over the US, next over Europe, then over Asia.
> This was very popular at the time, and would likely be welcomed again.
> I would suspect that a 'tundra-inclined orbit', fixed over the US as the
> Sirius Radio Sats are, would not be as internationally well supported.
>    /;^)
> --
>   <- WB5RMG is Alan Sieg  *  http://wb5rmg.somenet.net ->
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Mark Lockwood
Former Prefect, Metropolitan Rocketry Association 2006-2007
TRA # 9863
NAR #86042

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