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Re: Satellite control via Iridium?



Hi folks,

On Sun, 09 Feb 2003 19:09:04 +0100, Johann Lochner asked:

> How feasible is LEO satellite control via the Iridium or any other
> existing satellite constellation? 
> 
> Imagine being able to access your satellite wherever it is in its
> orbit, at whatever time is convenient!  Don't have any numbers
> yet, but a quick comparison of LEO to earth-based operations led
> to the following lists of differences: 

On Sun, 9 Feb 2003 20:17:04 -0500, Don Woodward responded:

> Iridium satellites have no way to link to UO-22 or any other
> amateur satellite. 

No intention to use UO-22 for this.  Tried to demonstrate that solar 
powered, remote (weather) stations (in Antarctica), using both ham 
satellites and commercial constellations as gateways to the outside 
world, are not only feasible but highly successful in practice.

The idea is to give ham satellites (which are also "remote stations") 
the ability to link to commercial constellations in this way, leading 
to a number of useful applications.

I am currently most interested in controlling ham satellites via the 
commercial constellation.  It's like always having the bird above 
your horizon.  ;-)

One could also use the constellation to send data (generated on-board 
or captured on a ham uplink, for example) to the Internet.  Something 
like an APRS EMERGENCY beacon could be relayed in near real-time even 
when no sat-gate coverage is available.

It will be even better if we build our own constellation of LEO ham 
birds over the longer term.  More coordination between educational 
institutions and other satellite organizations around the world will 
be required, though.

On Sun, 9 Feb 2003 23:19:59 EST, Roger Kola asked:

> > Any additions to these lists or feedback on the importance of
> > listed factors would be much appreciated. 
> 
> Cost?

The Antarctic weather station phones an ISP in California at around 
$0.92 (US) per minute (university rate).  Not sure about bandwidth.

On Mon, 10 Feb 2003 14:05:22 -0600, Robert Oler wrote:

> Sorry I really wasnt clear in the response.  What we looked at was
> using Iridium (or any of the new comm systems) as a communication
> mode for LEO satellites.  Not any one currently in orbit but coming
> up with a communications package.  Our "market" if you will was
> concieved primarily as commercial payloads on ISS. 
> 
> Instead of having to "buy" TDRSS time our theory (back in the days
> when there were a lot of "commercial" payloads envisioned for ISS)
> was that we would sell comm "by the line"...using very "small"
> antennas etc. 
> 
> We ran some pretty good computer simulations and figured out how
> to tackle the obvious problems.  Our main obstacle of course was
> that it became clear pretty quickly that ISS wasnt going to have
> substantial commercial payloads and NASA will use TDRSS forever. 

Thanks for the interesting info in both your messages, Robert.  It 
then seems that there are no real technical show-stoppers?

73 de ZR1CBC, Johann.
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