[amsat-bb] Re: sirius orbit name?

[Luc Leblanc]

On 21 Feb 2008 at 10:29, Jim Jerzycke wrote:

> The Sirius birds are in an "Inclined Orbit".
> It's explained more in the WikiPedia entry, about half
> way down the page.
> http://en.wikipedia.org/wiki/Sirius_radio
> 
> 73, Jim  KQ6EA
> 
> --- "Auke de Jong, VE6PWN" <sparkycivic at shaw.ca>
> wrote:
> 
> > Hi all,
> > What, if any, is the name given to the type of orbit
> > that the three "Sirius" broadcast satellites use? 
> > It shows as a figure-eight and altitude is between
> > 24000KM, and 47000KM. 
> > 
> > Auke de Jong
> > VE6PWN
> > DO33go
> > Edmonton, AB

Is this type of orbit can be a solution for the next HEO?

Tundra orbit is a type of highly elliptical orbit with a high inclination (usually near 63.4°) and an orbital period of one sidereal day 
(almost 24 hours).
A satellite placed in this orbit spends most of its time over a chosen area of the Earth, a phenomenon known as apogee dwell.

These are conceptually similar to Molniya orbits which have the same inclination but half the period (about 12 hours). 
The only user of Tundra orbits is Sirius Satellite Radio, which operates a constellation of three satellites.

References:http://en.wikipedia.org/wiki/Tundra_orbit

> 


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Luc Leblanc VE2DWE
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