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Tuesday, September 20, 2005

Study of the anomalous acceleration of Pioneer 10and 11

Good day again,

Dr. Slava G. Turyshev, one of the scientists doing a study of the anomalous
acceleration of Pioneer 10 and 11, is coming up to NASA Ames this Thursday
to give a talk on the subject.

Being no longer employed at Ames, I have had to ask for visitor passes to
continue copying the Pioneer 10 and 11 Master Data Record (MDR) files so
that I could put the whole mission raw data on DVDs.

I have completed that task and Viktor Toth has written a "C++" program to
read the science and engineering sub-com data and convert the binary data to
analog values. This is the same data I had displayed with my LabVIEW
programs earlier at Ames when we were still in communication with Pioneer

Dr. Turyshev thought that the information on the temperature history might
be of use in their research and I have given him a set of the DVDS and
Viktor has provided him with an MDR reader. (only 12 DVDs and you have both
Pioneer 10 and 11 data from beginning to end. That is 30 years of data on
my laptop. :-))

As a result of talking with Dr. Turyshev I have been reading up on their
work and trying to understand some of the material I have on the work of the
DSN in tracking the Pioneers over the years. This has been like trying to
learn a new language but I am learning a lot about the Pioneers.

I suggested to Ames personnel that it might be nice if Dr. Turyshev's talk
was streamed to the web but I have not heard if they will do so. (not being
on base, I don't get to read the center e-mails either.)

Even if you can't view the talk you might like to look at the links below.
The 21 page pdf is a larger file but the presentation images are colorful.
The 55 page pdf is a smaller file but much more reading (and re-reading).
If you want to know what was checked and rechecked in their search for what
might account for the apparent slowing of the Pioneers, this will show you.

Sorry, with all my reading and driving over the hill to Ames, my posts to
this lunar-update list have been spotty at best. (now know what a back yard
and garden are too.)

It would seem you folks have other irons in the fire too. The lunar-update
list is now a 998 readers.

Thanks for looking up with me.

Larry Kellogg

larry.kellogg at
21 page, 3 Mb PDF of Power Point Presentation on
Study of the anomalous acceleration of Pioneer 10 and 11
55 page, 1.5 Mb PDF of indepth coverage of
Study of the anomalous acceleration of Pioneer 10 and 11

General Relativity and Quantum Cosmology, abstract

From: Slava G. Turyshev [view email]
Date (v1): Thu, 19 Apr 2001 22:42:49 GMT (834kb)
Date (revised v2): Tue, 15 May 2001 20:55:26 GMT (835kb)
Date (revised v3): Tue, 5 Feb 2002 21:05:21 GMT (851kb)
Date (revised v4): Thu, 11 Apr 2002 20:28:10 GMT (851kb)
Date (revised v5): Thu, 10 Mar 2005 23:44:33 GMT (850kb)

Study of the anomalous acceleration of Pioneer 10 and 11
Authors: John D. Anderson, Philip A. Laing, Eunice L. Lau, Anthony S. Liu,
Michael Martin Nieto, Slava G. Turyshev
Categories: gr-qc astro-ph
Comments: Version 4, of 11 Apr. 2002, with errata appended
Report-no: LA-UR-00-5654
Subj-class: General Relativity and Quantum Cosmology; Space Physics
Journal-ref: Phys.Rev. D65 (2002) 082004

Our previous analyses of radio Doppler and ranging data from distant
spacecraft in the solar system indicated that an apparent anomalous
acceleration is acting on Pioneer 10 and 11, with a magnitude a_P ~ 8 x
10^{-8} cm/s^2, directed towards the Sun (anderson,moriond). Much effort has
been expended looking for possible systematic origins of the residuals, but
none has been found. A detailed investigation of effects both external to
and internal to the spacecraft, as well as those due to modeling and
computational techniques, is provided. We also discuss the methods,
theoretical models, and experimental techniques used to detect and study
small forces acting on interplanetary spacecraft. These include the methods
of radio Doppler data collection, data editing, and data reduction.
There is now further data for the Pioneer 10 orbit determination. The
extended Pioneer 10 data set spans 3 January 1987 to 22 July 1998. [For
Pioneer 11 the shorter span goes from 5 January 1987 to the time of loss of
coherent data on 1 October 1990.] With these data sets and more detailed
studies of all the systematics, we now give a result, of a_P = (8.74 +/-
1.33) x 10^{-8} cm/s^2. (Annual/diurnal variations on top of a_P, that leave
a_P unchanged, are also reported and discussed.)

Full-text: PostScript, PDF, or Other formats

References and citations for this submission:
SLAC-SPIRES HEP (refers to , cited by, arXiv reformatted);
CiteBase (autonomous citation navigation and analysis)

Thanks for looking up with me.
- LRK -



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