Re: Another out of control comsat?

Philip Chien (kc4yer@amsat.org)
Fri, 12 Mar 1999 16:40:51 -0500

"Brian Hunter" <bkh@chem.QueensU.CA> said:

>I have observed [Satcom GE-3] several times over the past two months.   I had
>convinced myself that it was out of position.  I usually find Geosynchronous
>objects by plotting their position in a star field and following a star
>until it 'catches up' with the satellite.  In the case of GE-3 it was always
>almost exactly one minute early; that it to say, east of where it was
>supposed to be.  Of course, I could have been seeing another object and made
>serveral attempts to find the real GE-3 or identify another nearby object.
>In fact, about two weeks ago, a new elset put GE-3 right where I was seeing
>it.
>
>This raises three possibilities:  they may be moving it or, in the process
>of moving it, lost control or, it simply failed.
>
>If the snow clears, I'll have a look for it.

Apparently they got the satellite back under control, all programming's
back in their normal places now.

The satellite has remained in its proper location throughout its operating
life, otherwise I wouldn't receive any signal.

Could it be possible that the moving satellite you're watching is actually
another satellite which is in the same vicinity?

According to news stories they lost one of the gyroscopes.  Presumably this
would have put the spacecraft in to a spin.  The ground controllers would
have had to transmit signals to the tracking telemetry and control (TT&C)
omni-directional antenna which wouldn't be affected much by the spin and
send commands to instruct a backup gyro to activate or fire thrusters to
cancel the spin.



Philip Chien, KC4YER
Earth News
world (in)famous writer, science fiction fan, ham radio operator,
all-around nice guy, etc.