The Pioneer effect and Spacecraft flyby anomalyby SinghRP Tags: anomaly, effect, flyby, pioneer, spacecraft 

#1
Feb2813, 10:49 AM

P: 73

Does general relativity explain the Pioneer effect and the spacecraft flyby anomaly? I have seen several papers on those two topics but no GR explanation.




#2
Feb2813, 11:02 AM

Mentor
P: 28,791

There appears to be no mystery with these space crafts. Did you miss this news?
http://physicsworld.com/cws/article/...malyruledout Zz. 



#3
Feb2813, 11:45 AM

P: 73

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. 



#4
Feb2813, 12:33 PM

Sci Advisor
Thanks
P: 3,852

The Pioneer effect and Spacecraft flyby anomaly 



#5
Feb2813, 12:40 PM

PF Gold
P: 717

AFAIK, the flyby is still an open anomaly (e.g. http://ntrs.nasa.gov/archive/nasa/ca...2009009651.pdf and http://arxiv.org/abs/1210.7333) 



#7
Feb2813, 02:13 PM

P: 73

This is what I know so far.
1. The Pioneer anomaly is due to thermal (kinetic) effect. Probably heat is from the spacecraft itself. 2. I believe only the NEAR spacecraft to an asteroid showed some significant flyby effect around Earth. At present they have fitted a curve with the data. They have accounted for Earth's varying gravitational filed. Etc., etc. GRT needs to explain it. It has not; I wonder why not. This could be a crucial test for GRT! A physicist friend thinks it is specialrelativistic effect. But I can't say anymore here due to the Forum's rules. I will come back here after his paper is published. Thanks muchly. 



#8
Feb2813, 11:13 PM

Emeritus
Sci Advisor
PF Gold
P: 5,500

The Pioneer anomaly was completely bogus:
Iorio, "Does the Neptunian system of satellites challenge a gravitational origin for the Pioneer anomaly?," http://arxiv.org/abs/0912.2947 F. Francisco, O. Bertolami, P. J. S. Gil, J. Páramos, "Modelling the reflective thermal contribution to the acceleration of the Pioneer spacecraft," http://arxiv.org/abs/1103.5222 Turyshev, Toth, et al. http://arxiv.org/abs/1204.2507 The flyby anomaly is not as well understood, but Toth thinks it's just a data analysis artifact due to switching between solarsystem barycentric coords and geocentric coords. Anderson had an empirical formula for the anomaly, but the formula predicted an anomaly for Rosetta, and in fact no anomaly was observed for Rosetta. 



#9
Mar113, 08:52 AM

P: 73

Thank you all for your responses. I agree with bcrowell.
1. Has someone investigated the effect of variations in the Earth's gravitational field or in the classical gravitational constant on the Pioneer effect and/or the Earth spacecraftflyby effect? 2. Can someone get me in contact with one at NASA who could provide me with related flyby data, particularly how the osculating orbit was determined? 



#10
Mar613, 12:02 PM

PF Gold
P: 17

arXiv: grqc/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. 



#11
Mar613, 12:19 PM

Mentor
P: 28,791

Zz. 



#12
Mar713, 07:24 AM

Mentor
P: 10,786





#13
Mar713, 08:40 AM

P: 73

Thanks for your responses. I agree with those who pointed out that the Pioneer effect and the spacecraft flybys “mystery” are not clearly understood. They can’t be with our current knowledge of gravitation. I tried to explain the two effects with GRT – no success.
I would not trust observations claiming accelerations as small as 10**10 m/s/s. Also  this is the acceleration they claim that the galaxies in the universe are accelerating at! Thanks to davidf32, who pointed out that the effects were gradual! I DID NOT KNOW THAT. Applying my physicist’s intuition, I think the effects could be due to variations in the classical gravitation constant G. Dirac said that a long, long time ago that G was not constant. Now, why and how G would be varying, I don’t know. How can I get the Pioneer and flyby data from NASA? So far, I have not succeeded. 



#14
Mar713, 11:19 AM

Mentor
P: 16,472

Thread closed. 


Register to reply 
Related Discussions  
Looking for someone who can do calculations on flyby anomaly.  Astrophysics  9  
Will GR ever explain the flyby anomaly?  Special & General Relativity  17  
With the Pioneer anomaly out of the way, could GOCE measurements account for flyby?  Astrophysics  2  
Flyby Anomaly  General Astronomy  7  
Flyby anomaly trajectories  Astrophysics  1 