The Pioneer Anomaly Options

[ljk4-1]

http://www.issi.unibe.ch/teams/Pioneer/

The Pioneer Explorer Collaboration
Investigation of the Pioneer Anomaly at ISSI

First Team Meeting at ISSI in Bern, Switzerland
November 7-11, 2005

Focus: the Pioneer anomaly

To date, the Pioneer 10 and 11 spacecraft are the most precisely navigated deep-space vehicles. However, as indicated by their radio-metric data, the Pioneers’ orbit reconstructions were limited by a small, anomalous, constant, blue-shifted, Doppler frequency drift of approximately 6 x 10^-9 Hz/s. The drift can be interpreted as due to a constant sunward acceleration of a_P = (8.74 ± 1.33) 10^-10 m/s^2. This interpretation has become known as the Pioneer anomaly.

Although the most obvious explanation would be that there is a systematic origin to the effect, the limited set of the analyzed data does not support any of the suggested mechanisms. We assert that analysis of the entire existing Pioneer data is vital to understanding the anomaly and, hopefully, to finding its origin. Indeed, analysis of the entire existing Pioneer data record is critical in attacking the anomaly on two fronts: (i) an analysis of the early, not rigorously analyzed, data could yield a more accurate direction of the anomaly and hence might help to determine its origin; (ii) by using the entire data set, from 1972 to 2002, one could study the temporal evolution of the anomaly and determine if it is due to on-board nuclear fuel inventory and related heat radiation or other mechanism.

Goal: analysis of the entire Pioneer 10/11 data record

The limited data analyzed previously allowed the detection of the anomaly in the Pioneer data, but not a determination of its origin. With new knowledge of all on-board processes and a diverse team, we propose a two-step process in understanding the origin of the anomaly, namely: (i) analysis of the entire set of existing Pioneer 10 and 11 data, obtained from first launch to the last telemetry received from Pioneer 10, on 27 April 2002, when it was at a heliocentric distance of 80 AU. This data could yield critical new information about the anomaly. If the signal is confirmed and is not due to an on-board systematic, (ii) we will use our new knowledge to develop an instrumental package that will be capable to provide an independent confirmation of the anomaly. We will also study a design for a dedicated mission to explore the anomalous behavior of the Pioneer spacecraft.

Significance: finding the origin of the Pioneer anomaly

This ISSI investigation could lead to a determination of the origin of the anomaly and to a characterization of its physical properties. The proposed investigation is scientifically important, it is timely, and is well situated in Europe. The investigation would be an excellent example to demonstrate the value of interdisciplinary teams in addressing complex problems in fundamental physics and in application of new technologies in spacecraft and mission designs. The results of this study could find their way into many other areas of space-exploration applications in the near future. The most important outcome of this study will be the understanding of the Pioneer anomaly.

http://www.issi.unibe.ch/teams/Pioneer/

[edstrick]

ljk4-1: "...The Pioneer Explorer Collaboration -- Investigation of the Pioneer Anomaly at ISSI.."

I totally concur with the proposed analysis. We have an "anomaly". Not an "Anomaly" or an "ANOMALY" (if you get what I mean...).

We have an APPARENT force acting on the spacecraft. The best modelling has been unable to explain this anomaly in terms of systematic internally generated forces on the spacecraft, or known, modelable external forces acting on the spacecraft. We now need to extract the most information possible from the mission's data to see how the force varies with 1.) mission phase, 2.) radial location in solar system, and 3.) azimuth/inclination in solar system.

For example, if a reanalysis shows no anomalous acceleration before Jupiter flyby and identical accelerations afterwards... that would suggest an effect arising in an unknown effect on the spacecraft of the Jovian system environment..... particularly the extreme radiation environment.

For another example...Pioneer 11 flew "across" the solar system in a significantly inclined orbit between the Jupiter encounter and it's Saturn encounter, getting a foretaste of out-of-ecliptic science before Ulysses. If a reanalysis shows a force varying with inclination or angle around the sun in the ecliptic and then a relatively constant force after Saturn flyby puts Pioneer 11 on an escape trajectory...... Hmmmmmm.....!

[Guest_Richard Trigaux_*]

Thanks ljk4-1 for your interesting contribution. And edstrick too

To analyse the existing set of data is obviously the first thing to do before building a space probe to investigate a gaz leak on Pioneer.
-Is the effect real?
-Is it constant, or depending on distance, attitude, fuel aging, direction, planet neighbouring, distance from the ecliptic?
All this would give us clues about its nature: gravitation, electromagnetic, solar wind, local reaction...

By the way it is said that the computers able to read the Pioneer data are to be scraped by the NASA. The first thing to do is obviously to save the data on modern supports. New domain for archaeology: rumaging in old computers magnetic bands.

edstrick, I never heard that the word "anomaly" bears a capital letter, in any of its uses. The Pioneer anomaly may have a very extraordinary explanation, for instance that the probe was followed by a spaceship from another civilization, or that it was used by yogis to demonstrate their supernatural powers. Simply such kind of explanations can be envisioned only after all the other explanations failed. More likely the Pioneer anomaly bears the possibility of some fundamental discovery in physics or in astronomy, so it is worth the study. But there are many chances that we simply find a gaz leak, thruster malfunction or something trite in this style.

But of course I did not missed your point about ANOMALIES! I am no more interested than you by people who spread false informations and false theories: they only muddle things. If there is somewhere something really unexplained, they may rather spoil the discovery than encourage its study.

[deglr6328]

sooooo did the planetary soc. get the data or what...? They haven't updated on us the status of thier original $250K begathon since like March.

[edstrick]

<grin> by "anomaly" I mean an ordinary scientific/engineering unexplained datum due to inadequate modeling, systematic error in measurements, etc.... like the false indications that there was a 10'th planet making Neptune "wander", triggering the search that found Pluto.

An "Anomaly" (tone of voice emphasis implied) would be something that really starts to look like it suggests new astronomy, new physics.... something that is well defined enough and stubborn enough after sustained efforts to make it go away, that people (not just the arm-waving fringe) start to work hard on resolving it. The solar neutrion flux anomaly was one... solved by the confirmation that solar neutrinos change type en-route from the sun, so we only detect 1/3 of them with the original detectors.

And of course ANOMALY (capslock, funny font, guy with tin hat handing out mimeographed treatises to anybody he can buttonhole at a scientific meeting) is what the Hoaxland crowd assume it's most likely to be. (eyeballs rolled expression).

[Guest_Richard Trigaux_*]

<grin>  by "anomaly" I mean an ordinary scientific/engineering unexplained datum due to inadequate modeling, systematic error in measurements, etc.... like the false indications that there was a 10'th planet making Neptune "wander", triggering the search that found Pluto.

An "Anomaly"  (tone of voice emphasis implied) would be something that really starts to look like it suggests new astronomy, new physics.... something that is well defined enough and stubborn enough after sustained efforts to make it go away, that people (not just the arm-waving fringe) start to work hard on resolving it.  The solar neutrion flux anomaly was one... solved by the confirmation that solar neutrinos change type en-route from the sun, so we only detect 1/3 of them with the original detectors.

And of course ANOMALY (capslock, funny font, guy with tin hat handing out mimeographed treatises to anybody he can buttonhole at a scientific meeting) is what the Hoaxland crowd assume it's most likely to be. (eyeballs rolled expression).

Thank you for the nuances. The Pioneer anomaly if likely of the first kind (anomaly) but there is enough chance it is of the seconc kind (Anomaly) so that it is worth studying it (and re-examining the whole data set is definitively the best to start with).

By the way, the custom of wearing tin-hats comes from the idea that naughty aliens influence us by telepathy. But if telepathy exists, it is likely not an electromagnetic phenomenon, so the tin hat is of no use.

[edstrick]

Aliens?... I thought it was the CIA and FBI.... or maybe they are space aliens here to control us!

NATIONAL OUTQUIRER
(Picture of Michael Jackson, Elizabeth Taylor, and H. Ross Perot)
Headline: CELEBRITY SPACE ALIENS LIVING AMONG US.

(HRP is obviously a disguised Ferengi... the ears.. the nose.. the money...)

[Guest_Richard Trigaux_*]

Aliens?... I thought it was the CIA and FBI....

They do not need telepathy for this, they have tele...vision.

There are rumors too of electromagnetic weapons able of having effects of the brain, such as make us hear voices. Far-fetched, but not completelly impossible I think. But if ever there is one day a government pervert enough to use such weapons against its citizens, it will be that the society would have gone very very wrong far before...

[edstrick]

You know what the problem is with make-believe paranoia?

(looking around suspiciously...)

YOU'RE PROBABLY RIGHT!

[Guest_Richard Trigaux_*]

You know what the problem is with make-believe paranoia?

(looking around suspiciously...)

YOU'RE PROBABLY RIGHT!

AAAAAARRRGGHH

[ljk4-1]

Astrophysics, abstract
astro-ph/0504367
From: Gary Page [view email]
Date (v1): Sun, 17 Apr 2005 17:04:48 GMT (32kb)
Date (revised v2): Sat, 1 Oct 2005 13:46:27 GMT (43kb)

Utilizing Minor Planets to Assess the Gravitational Field in the Outer Solar System

Authors: Gary L. Page, David S. Dixon, John F. Wallin

Categories: astro-ph

Comments: Added substantial new material dealing with ability to observed effects addressed in paper

The twin Pioneer spacecraft have been tracked for over thirty years as they headed out of the solar system. After passing a heliocentric distance of 20 AU, both exhibited a systematic error in their trajectories that can be interpreted as a constant acceleration towards the sun and that has come to be known as the Pioneer Effect.

Spacecraft systematics are its most likely explanation, but there have been no convincing arguments that that is the case. The alternative, that the Pioneer Effect represents a real phenomenon, is very appealing for many reasons. What is lacking is a means of measuring the effect, its variation, its potential anisotropies, and its region of influence.

We show that minor planets provide an observational vehicle for investigating the gravitational field in the outer solar system, and thus provide a means of measuring the Pioneer Effect and potentially to either support or refute its existence as a real phenomenon. Minor planets can be used for this purpose because they have a large mass and are large and bright enough to be observed for useful intervals.

Thus, even if the Pioneer Effect does not represent a new physical phenomenon, minor planets can be used to probe the gravitational field in the outer solar system. Since there are very few intermediate range tests of gravity at the multiple AU distance scale, this is a worthwhile endeavor in its own right. It might even be possible to differentiate between the predictions of alternative explanations for the Pioneer Effect.

http://arxiv.org/abs/astro-ph/0504367

[ljk4-1]

Paper: astro-ph/0506281

replaced with revised version Mon, 24 Oct 2005 20:43:50 GMT (41kb)

Title: Analytic Gravitational-Force Calculations for Models of the Kuiper Belt,
with Application to the Pioneer Anomaly

Authors: Michael Martin Nieto

Comments: 11 pages, 8 figures, final corrections for publication

Report-no: LA-UR-05-4414

Journal-ref: Phys. Rev D 72 (2005) 083004

We use analytic techniques to study the gravitational force that would be produced by different Kuiper-Belt mass distributions. In particular, we study the 3-dimensional rings (and wedge) whose densities vary as the inverse of the distance, as a constant, as the inverse-squared of the distance, as well as that which varies according to the Boss-Peale model. These analytic calculations yield physical insight into the physics of the problem. They also verify that physically viable models of this type can produce neither the magnitude nor the constancy of the Pioneer anomaly.

\\ ( http://arXiv.org/abs/astro-ph/0506281 , 41kb)

[ljk4-1]

Paper (*cross-listing*): gr-qc/0511026

Date: Sun, 6 Nov 2005 02:40:04 GMT (162kb)

Title: Gravitational solution to the Pioneer 10/11 anomaly

Authors: J. R. Brownstein and J. W. Moffat

Comments: 11 pages, 4 figures, 1 table
\\
A fully relativistic modified gravitational theory including a fifth force
skew symmetric field is fitted to the Pioneer 10/11 anomalous acceleration. The
theory allows for a variation with distance scales of the gravitational
constant G, the fifth force skew symmetric field coupling strength omega and
the mass of the skew symmetric field mu=1/lambda. A fit to the available
anomalous acceleration data for the Pioneer 10/11 spacecraft is obtained for a
phenomenological representation of the "running" constants and values of the
associated parameters are shown to exist that are consistent with fifth force
experimental bounds. The fit to the acceleration data is consistent with all
current satellite, laser ranging and observations for the inner planets.

\\ ( http://arXiv.org/abs/gr-qc/0511026 , 162kb)

[Guest_Myran_*]

Calculations using the 'MOND' theory (Modified Newtonian dynamics) also have been applied and did fit well with the Pioneer data. No fifth force needed in that case.

Some more on MOND here:
http://www.astro.umd.edu/~ssm/mond/

[Guest_Richard Trigaux_*]

I wonder if we could do any theory of any kind, adjust parametres and obtain a fit with anything.

But if the fit goes for not only Pioneer data, but all similar data, it is more intersting. Not an evidence of any given theory, but a last of a common mechanism.