Re: Observing TDRS maneuvers

Philip Chien (
Thu, 27 Jun 1996 06:41:59 -0400

Jeff Barker <> stated:
>     Viewing any geostationary satellite is a challenge but I don't think
>     that the operation of the thrusters will result in any signature that
>     would help to see that TDRS satellite move.  Hydrazine is a
>     monopropellant that provides hot gas propulsion.  The gas is clear.
>     There is no orange flame.  Unless you have an IR telescope, the
>     satellite looks the same whether the thrusters are firing or not.

something to add is the hydrazine thrusters are about the size of a
thimble.  If memory serves they produce about one ounce force of thrust.
Colliqually thrusters like that are known as 'mouse-fart' thrsters.

I'd suspect that Jeff is correct and unless you're using an infrared
telescope you won't see any thruster firings from that distance.

Philip Chien, Earth News - space writer and consultant  PCHIEN@IDS.NET
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