Updated my Horizons data for ISEE-3 today and found this nice note:
UPDATE (2014-Jun-23):
Trajectory updated to JPL solution #32 (s32), based on 42 coarse Arecibo plane-of-sky angular measurements spanning May 22 – Jun 23 …
Upon updating things and re-acquiring the signal we have so far a solid signal tracking with little change to frequency. We will see how it performs in next few hours but previously we would observe a 3 Hz per hour change in the frequency. But of course that can just be the unlocked carrier drifting…
Here is screenshot just after re-acquisition.
