[amsat-bb] Re: old satellites

w7lrd@comcast.net w7lrd at comcast.net
Tue Mar 17 11:39:01 PDT 2009

clever thinking Dave.  There some "experts" on this BB that know the answer
73 Bob W7LRD

----- Original Message -----

From: David - KG4ZLB 

To: Hans Johnson 

Cc: amsat-bb at amsat.org

Sent: Tue, 17 Mar 2009 17:28:00 +0000 (UTC)

Subject: [amsat-bb] Re: old satellites

I was reading about the newly launched GOCE satellite and the fact that 

its mission will end when its 40kg tank empties - that of course may be 

a long time coming but as it has an S band transmitter, could this not 

be tweaked for us once the mission is complete?

And thinking further, for these satellites could amateur radio gear be 

carried so that it could be activated once the main mission is complete? 

Doing this over a number of years would provide a ready made supply of 

new birds over a period of time.

I suppose logistics and cost will be the factor but its an idea and 

would give us at least something!





Hans Johnson wrote:

> Furthermore, from what I understand, international agreements (or at least

> implicit agreements) now require the operators to vent any remaining fuel.

> This is to prevent the satellite from exploding at some point in the future

> due to either the (rather caustic) fuel corroding through the fuel tank, or

> a debris/micrometeorite hit.


> Once this is complete, the operators will then permanently shut down the

> satellite so that there is no chance of it interfering with the operational

> fleet.  The last thing they want is a semi-active satellite drifting past an

> operational satellite (at least from the POV of the earth station) and

> potentially confusing tracking antennas, or otherwise interfering with

> revenue traffic.


> As far as shifting them to amateur frequencies, I doubt it's physically

> possible.  In order to get the Tx/Rx isolation they need, the satellites

> will be using cavity filters, so unless you're very close to their passband,

> there's no hope.  Heck, in my day job, we have to use different filters if

> we want to operate in extended ku-band filters.


> Regards,


> Hans Johnson



> On Thu, Mar 12, 2009 at 3:52 PM, Wayne Estes wrote:








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