The Pioneer effect and Spacecraft flyby anomaly

Meanwhile, have you read whether GRT explains either or both?

I will access the link, read, and come back to you.

Meanwhile, have you read whether GRT explains either or both? Please be specific; will appreciate it.

SinghRP, I have read the link, and it gives a full explanation. Suggest you do too!

I don't think the linked article/paper explains the Flyby anomaly, or does it?

There appears to be no mystery with these space crafts. Did you miss this news?

http://physicsworld.com/cws/article/...maly-ruled-out

Zz.

It is interesting to look at the actual data for the anomalous acceleration. it is available at:
arXiv: gr-qc/0104064v5
What one sees is three distinct signatures;
(1) The effect gradually appears over a distance of about 5 AU or so reaching a maximum of about 10*10^-8 cm/sec^2 at 20 AU and staying more or less constant after that out to at least 70AU.
(2) There is a definite yearly small variation in the magnitude at a certain position related to the earth's rotation around the sun in its orbit
(3) There is a much larger (order of 100*10^-8 cm/sec^2) term with a period equal to the earth's period of rotation (24 hours)
IN view of these facts, the thermal explanation does not seem valid: It should appear much sooner than 5 AU, more or less all the time; it does not address either the small annual term or the diurnal large term. I don't believe the thermal explanation.
davidf32.

(1) The effect gradually appears over a distance of about 5 AU or so reaching a maximum of about 10*10^-8 cm/sec^2 at 20 AU and staying more or less constant after that out to at least 70AU.

(2) There is a definite yearly small variation in the magnitude at a certain position related to the earth's rotation around the sun in its orbit
(3) There is a much larger (order of 100*10^-8 cm/sec^2) term with a period equal to the earth's period of rotation (24 hours)

The annual and diurnal terms are very likely different
manifestations of the same modeling problem. The magnitude
of the Pioneer 10 post-fit weighted RMS residuals
of ≈ 0.1 mm/s, implies that the spacecraft angular position
on the sky is known to ≤ 1.0 milliarcseconds (mas).
(Pioneer 11, with ≈ 0.18 mm/s, yields the result ≈ 1.75
mas.) At their great distances, the trajectories of the
Pioneers are not gravitationally affected by the Earth.
(The round-trip light time is now ∼ 24 hours for Pioneer
10.) This suggests that the sources of the annual and
diurnal terms are both Earth related.
Such a modeling problem arises when there are errors
in any of the parameters of the spacecraft orientation
with respect to the chosen reference frame. Because
of these errors, the system of equations that describes
the spacecraft’s motion in this reference frame
is under-determined and its solution requires non-linear
estimation techniques. In addition, the whole estimation
process is subject to Kalman filtering and smoothing
methods. Therefore, if there are modeling errors in
the Earth’s ephemeris, the orientation of the Earth’s spin
axis (precession and nutation), or in the station coordinates
(polar motion and length of day variations), the
least-squares process (which determines best-fit values of
the three direction cosines) will leave small diurnal and
annual components in the Doppler residuals, like those
seen in Figures 17-18.

I think the effects could be due to variations in the classical gravitation constant G.