[amsat-bb] Re: Path to HEO

Luc Leblanc lucleblanc6 at videotron.ca
Sun Apr 28 17:29:08 PDT 2013

> Thanks,
> maybe I didn't make myself clear:
> LEO (low earth orbit) from 400 to 2000km or something like that
> HEO (high earth orbit) >20000km
> Going from 310 to 700km in a year is not doing us anything. We need a
> highly elliptical orbit (Apogee ~60000km, Perigee 900km) similar to AO-40
> to allow for cross continental communication.
> Stefan VE4NSA

On January 23 I was on UL mode with a DL and an Italian station i was just testing my new L Band amp and it was my 802 QSO on AO-40 my last 
one snif snif. The rest is old story who can be shared only with those guys who enjoy one of the best AMSAT satellite.

For those who just start to flirt with satellite here is how the story end 

On 25 January 2004, telemetry from the main battery was observed to go to an extremely low voltage by Stacey Mills (amateur radio call sign 
W4SM), a member of the Command Team. This caused the onboard Internal Housekeeping Unit (IHU) computer to cut power to the transponder 
payloads. Just prior to the loss of control of the satellite, the auxiliary battery came online in parallel with the main battery. When the 
main battery failed, it effectively short-circuited the auxiliary battery, killing the spacecraft. Many attempts were made to disconnect 
the main battery, but insufficient voltage was available to drive the relays. One day an open-circuit failure may occur in the main 
battery, in which case the spacecraft may come to life again. Though the command team believe that the main battery failure was probably a 
consequence of damage done during the event, and it is likely that similar damage was done to the auxiliary battery, making an eventual 
recovery of AO-40 unlikely.

What the story does not tell it is possible that a manual command was the culprit here but all the folks who work on the AO-40 project are 
also human and perfectible as you and me.

It is a refreshing breeze to start to hear HEO again so sorry for those who pass by to the eternal DX cluster.


Luc Leblanc VE2DWE
Quebec provincial Hamfest HTTP://www.hamfest.qc.ca


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