Tether orbit and prediction

Robert H. McNaught, Anglo-Australian Observatory (RMN@aaocbn2.aao.gov.au)
Fri, 15 Mar 1996 11:07:24 +1100 (EST)

Bill Bard wrote

>Regarding Bill Moore's comments, I wonder if you plot TSS's path across 
>the sky (using as current elements as possible) and compare it with the 
>observed path across the sky, which part of the tether agrees with the 
>predicted path? The satellite or partway down the tether?

I too have wondered about this.  Presumably it is the center of mass which
is the relevant factor and this must be in the upper half of the tether.
If the tether bends, the predicted point (center of mass) could be outside
what is visible!

I'm a bit rusty on how the orbits are updated.  If radar is used, what sort of
signal is produced from a sphere plus tether, and if only the sphere is
visible, it will be above the true center of mass and thus will produce
discrepant orbits depending on the difference between the two.

Rob McNaught