The Study of the Pioneer Anomaly:

The Study of the Pioneer Anomaly:
New Data and Objectives for New Investigation

Slava G. Turyshev, a
Viktor T. Toth, b
Larry R. Kellogg, c
Eunice. L. Lau, a and
Kyong J. Lee, a

a Jet Propulsion Laboratory, California Institute of Technology,
4800 Oak Grove Drive, Pasadena, CA 91109, USA
b vttoth.com, 3-575 Old St Patrick St., Ottawa ON K1N 9H5, Canada
c NASA Ames Research Center, Moffett Field, CA 94035, USA 1

1 Contractor to NASA Ames Research Center employed by Bendix Field Engineering Corporation early on and Orbital Sciences Corporation at the end of the Pioneer missions; presently retired.

Abstract

The Pioneer 10/11 spacecraft yielded the most precise navigation in deep space to date. However, their radiometric tracking data has consistently indicated the presence of a small, anomalous, Doppler frequency drift. The drift is a blue shift, uniformly changing with a rate of  6 × 10−9 Hz/s and can be interpreted as a constant sunward acceleration of each particular spacecraft of aP = (8.74 ±1.33) × 10−10 m/s2 (or, alternatively, a time acceleration of at = (2.92 ± 0.44) × 10−18 s/s2). This signal has become known as the Pioneer anomaly; the nature of this anomaly remains unexplained. We discuss the current state of the efforts to retrieve the entire data sets of the Pioneer 10 and 11 radiometric Doppler data. We also report on the availability of recently recovered telemetry files that may be used to reconstruct the engineering history of both spacecraft using original project documentation and newly developed software tools. We discuss possible ways to further investigate the discovered effect using these telemetry files in conjunction with the analysis of the much extended Pioneer Doppler data.

In preparation for this new upcoming investigation, we summarize the current knowledge of the
Pioneer anomaly and review some of the mechanisms proposed for its explanation. We emphasize the main objectives of this new study, namely i) analysis of the early data that could yield the true direction of the anomaly and thus, its origin, ii) analysis of planetary encounters, that should tell more about the onset of the anomaly (e.g. Pioneer 11’s Saturn flyby), iii) analysis of the entire dataset, that should lead to a better determination of the temporal behavior of the anomaly, iv) comparative analysis of individual anomalous accelerations for the two Pioneers with the data taken from similar heliocentric distances, v) the detailed study of on-board systematics, and vi) development of a thermal-electric-dynamical model using on-board telemetry. The outlined strategy may allow for a higher accuracy solution for the anomalous acceleration of the Pioneer spacecraft and, possibly, will lead to an unambiguous determination of the origin of the Pioneer anomaly.

Contents
1 Introduction 2
2 The Pioneer Anomaly and the Search for its Origin 5
2.1 The Pioneer Anomaly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2 Original Efforts to Explain the Anomaly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2.1 Effects with Sources External to the Spacecraft . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2.2 Study of the On-Board Systematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2.3 Computational Systematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.3 Recent Efforts to Explain the Anomaly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.3.1 Search for Independent Confirmation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.3.2 Conventional Physics Mechanisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.3.3 Possibility for New Physics? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3 Recovery of the Extended Pioneer Doppler Data Set 10
3.1 Doppler Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.2 Pioneer Doppler Data Formats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.2.1 ATDF – Archival Tracking Data File (Format TRK-2-25) . . . . . . . . . . . . . . . . . . 12
3.2.2 ODF – Orbit Data File (Format TRK-2-18) . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.3 Retrieval of the Pioneer Doppler Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.4 Current Status of the Data Recovery Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
4 Pioneer Telemetry and On-Board Systematics 16
4.1 Master Data Records . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.1.1 MDR Media and Data Organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.1.2 Data Integrity and Completeness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.1.3 Interpreting the Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.1.4 Decoding Analog Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.1.5 Software Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
4.2 Available Telemetry Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
4.3 What Can Telemetry Tell Us About the Spacecraft? . . . . . . . . . . . . . . . . . . . . . . . . . 24
5 A Strategy to Find the Origin of the Pioneer Anomaly 26
5.1 Analysis of the Earlier Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
5.2 Study of the Planetary Encounters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
5.3 Analysis of the Entire Data Span . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
5.4 Analysis of the Individual Trajectories for Both Pioneers . . . . . . . . . . . . . . . . . . . . . . . 30
5.5 Investigation of the On-Board Systematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
5.5.1 Radio Beam Reaction Force . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
5.5.2 Anisotropic Heat Reflection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
5.5.3 Differential Change of the RTG’s Radiant Emissivity . . . . . . . . . . . . . . . . . . . . . 34
5.5.4 Constant Electrical Heat Radiation as the Source . . . . . . . . . . . . . . . . . . . . . . . 35
5.5.5 Helium Expulsion from the RTGs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
5.5.6 Propulsive Mass Expulsion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
5.6 Building a Thermal/Electrical/Dynamical Model for the Pioneers . . . . . . . . . . . . . . . . . . 37
6 Conclusion

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http://arxiv.org/PS_cache/gr-qc/pdf/0512/0512121.pdf
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A bit selfish I know, but I don't want the Pioneer 10 and 11 missions to be lost to the general consciousness.

If you get to page 17 you can see some of what goes into pulling the health of the spacecraft out of the Master Data Records.

Was a lot of fun working in support of the Pioneer Missions.

Larry R. Kellogg