Re: Observing TDRS maneuvers
jbarker@arinc.com
Tue, 25 Jun 1996 14:44:20 -0400
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.
I got the following info from
http://shuttle.nasa.gov/sts-70/orbit/payloads/tdrs/index.html
Jeff Barker
jbarker@arinc.com
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TDRS Propulsion and attitude control
The TDRS propulsion subsystem is a monopropellant hydrazine system
which provides impulse for attitude control, unloading
momentum wheels, and velocity corrections for positioning and
stationkeeping. The propulsion subsystem propellant maximum
capacity is 1300 lb.
The system provides for a 10-year operational life and a 7-year
maximum storage life. The combines storage and operational
life is 11 years. The propellant budget is predicated on several use
and efficiency factors, including orbit insertion error
correction and lifetime attitude control and stationkeeping.
The propulsion subsystem consists of the following components:
2 propellant tanks
2 redundant groups of 12 thrusters
6 latching isolation valves
3 fill and drain valves
2 filters
pressure and temperature instrumentation
thermal management
plumbing
mounting brackets
To prevent firing of the TDRS thrusters in the orbiter payload bay,
the propulsion system is equipped with arm/disarm functions
in the ordnance arming unit.