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The Pioneer Anomaly
remcook
post Aug 16 2005, 04:27 PM
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http://www.planetary.org/news/2005/pioneer_anomaly_faq.html

The planetary society may be checking it out...

QUOTE
The Planetary Society has committed to raise the funds to preserve the priceless Pioneer data from destruction.


After years of analysis, but without a final conclusion, NASA, astonishingly, gave up trying to solve the "Pioneer Anomaly" and provided no funds to analyze the data. The Pioneer data exists on a few hundred ancient 7- and 9-track magnetic tapes, which can only be read on "antique" outdated computers. The agency is going to scrap, literally demolish, the only computers able to access and process that data in the next few months!
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edstrick
post Aug 30 2005, 08:52 AM
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Climate orbiter was not radar tracked, it was transponder tracked. You get precise distance, but have to model angular position on the sky from indirect data. One way to get precise relative position in the sky is differential interferometry, where one vehicle, say a mars orbiter, is a reference source, and the approaching vehicle's position relative to the reference can be measured.

The problem with Climate orbiter was not with the tracking data, it was modelling the trajectory based on that data when bogus information <incorrect spacecraft peturbation values from the momentum wheel offloading with thruster firing) was included in the solution. The nav team had recognized and been bothered the entire flight by considerably (several times?) larger trajectory calculation variations than normal, but not been able to find a cause of the error with available time and resource.

Polar Lander wiped out due to either 1.) a programming error in the descent software that was almost guaranteed to eat their lunch. or 2.) any of considerable number of design defects that added risk to the landing but weren't "smoking gun" errors.

The Pioneer anomaly is just that.. it's a departure of observations from very precise, but known imperfect calculations. We don't know if there's a physical something based on "deep" important physics, or if our engineering models of non-gravitational forces on the spacecraft are subtly wrong.

It will cost at least a few hundred million dollars to fly a mission that will convincingly and unambiguously prove an "important" physics cause is either present or not, and *PRECISELY* measure that effect if it exists as a function of distance from the sun. *** NOT TRIVIAL ***.

There are a lot of other research proposals and proposed space missions with equal or greater chances of testing and getting an important answer to "deep" physics questions that would cost the same or less than a Pioneer Anomaly mission. The best strategy is to pick the strongest tests with the greatest likelyhood of surprise, for the least amount of money and do or fly those..... and to pick tests that test fundamentally different possible suprises in deep physics. Things like dark matter detection experiments, gravity wave observatories, Dark energy investigations have far more chance per doller of real surprises than a pioneer anomaly mission. We need to keep it as an open question with the possibility of a mission, but right now, it seems a high risk, probably low yield mission for the money.
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Mongo
post Aug 30 2005, 07:12 PM
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QUOTE (edstrick @ Aug 30 2005, 08:52 AM)
There are a lot of other research proposals and proposed space missions with equal or greater chances of testing and getting an important answer to "deep" physics questions that would cost the same or less than a Pioneer Anomaly mission.  The best strategy is to pick the strongest tests with the greatest likelyhood of surprise, for the least amount of money and do or fly those..... and to pick tests that test fundamentally different possible suprises in deep physics.  Things like dark matter detection experiments, gravity wave observatories, Dark energy investigations have far more chance per doller of real surprises than a pioneer anomaly mission.  We need to keep it as an open question with the possibility of a mission, but right now, it seems a high risk, probably low yield mission for the money.

The problem with a 'dark matter' mission is that the putative dark matter is entirely hypothetical, and may not (I would say probably doesn't) exist. Stanley Milgrom's MOND theory or Jakob Bekenstein's TeVeS theory seems to me to explain the observations in question much more easily than any dark matter theory does. There are also indications that the effects ascribed to 'dark energy' may also be a natural result of a full MOND or TeVeS theory.

http://xxx.lanl.gov/abs/astro-ph/0504130

On the other hand, the so-called 'Pioneer Anomaly' appears to be genuine. The alternative explanations (solar wind, asymmetrical thermal radiation, etc.) appear to be several orders of magnitude too small to adequately explain the observed acceleration. I personally would say that a proper investigation of the 'Pioneer Anomaly' would be at least as important as Gravity Probe B, and could be mounted at a reasonable cost too. The spacecraft itself would be relatively inexpensive; the biggest cost would be the launch vehicle.

Here are links to papers discussing possible approaches to a mission:

http://xxx.lanl.gov/abs/astro-ph/0504634
http://xxx.lanl.gov/abs/astro-ph/0409373
http://xxx.lanl.gov/abs/gr-qc/0409117

Bill
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Bob Shaw
post Aug 31 2005, 11:28 AM
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Bill:

Your links, er, don't!

Bob Shaw


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Remember: Time Flies like the wind - but Fruit Flies like bananas!
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Mongo
post Aug 31 2005, 02:45 PM
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That's strange; I just clicked on them and they sent me to the reports that I had referenced...

If they still don't work, I suppose that you can just go to

http://xxx.lanl.gov/find/astro-ph

and do a search for 'Pioneer Anomaly'. Or else just type out the links on your address bar.

Bill
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Posts in this topic
- remcook   The Pioneer Anomaly   Aug 16 2005, 04:27 PM
- - remcook   Some background reading... http://arxiv.org/find/...   Aug 16 2005, 04:40 PM
|- - tedstryk   Won't New Horizons be spin stabilized when not...   Aug 16 2005, 06:53 PM
|- - Jeff7   QUOTE (remcook @ Aug 16 2005, 11:40 AM)Some b...   Aug 17 2005, 07:09 PM
- - remcook   Quote from alan stern: QUOTE Yes, we spin most of...   Aug 16 2005, 07:43 PM
- - Richard Trigaux   Could not the Pioneer tapes be saved on a more mod...   Aug 17 2005, 06:37 AM
- - remcook   QUOTE It looks like the Pioneers have long stopped...   Aug 17 2005, 08:09 PM
- - deglr6328   QUOTE (remcook @ Aug 17 2005, 08:09 PM)that...   Aug 17 2005, 11:10 PM
|- - Bob Shaw   QUOTE (deglr6328 @ Aug 18 2005, 12:10 AM)Not ...   Aug 18 2005, 08:24 AM
- - Richard Trigaux   As far as I understand from readings in the press,...   Aug 18 2005, 06:59 AM
|- - The Messenger   QUOTE (Richard Trigaux @ Aug 17 2005, 11:59 P...   Aug 26 2005, 09:08 PM
|- - antoniseb   QUOTE (The Messenger @ Aug 26 2005, 04:08 PM)...   Aug 26 2005, 10:42 PM
|- - The Messenger   QUOTE (antoniseb @ Aug 26 2005, 03:42 PM)The ...   Aug 29 2005, 05:25 PM
|- - algorimancer   It seems to me that a simple means of checking thi...   Aug 29 2005, 05:40 PM
|- - The Messenger   QUOTE (algorimancer @ Aug 29 2005, 10:40 AM)I...   Aug 29 2005, 06:12 PM
- - edstrick   Climate orbiter was not radar tracked, it was tran...   Aug 30 2005, 08:52 AM
|- - Mongo   QUOTE (edstrick @ Aug 30 2005, 08:52 AM)There...   Aug 30 2005, 07:12 PM
|- - Bob Shaw   Bill: Your links, er, don't! Bob Shaw   Aug 31 2005, 11:28 AM
|- - Mongo   That's strange; I just clicked on them and the...   Aug 31 2005, 02:45 PM
|- - Bob Shaw   QUOTE (Mongo @ Aug 31 2005, 03:45 PM)That...   Aug 31 2005, 03:42 PM
|- - Mongo   QUOTE (Bob Shaw @ Aug 31 2005, 03:42 PM)I pro...   Aug 31 2005, 03:57 PM
- - The Messenger   I am at least as interested in the flight path ecc...   Aug 31 2005, 06:56 PM
|- - antoniseb   QUOTE (The Messenger @ Aug 31 2005, 01:56 PM)...   Aug 31 2005, 09:58 PM
- - dvandorn   Hmmm... well, the effect must be very, very minor ...   Aug 31 2005, 07:24 PM
- - Richard Trigaux   Thanks to recent posters this thread took an inter...   Sep 3 2005, 09:07 AM
|- - jamescanvin   QUOTE (Richard Trigaux @ Sep 3 2005, 07:07 PM...   Sep 5 2005, 12:13 AM
- - Richard Trigaux   A rather interesting prospective explanation of th...   Sep 3 2005, 10:07 AM
- - remcook   some people seem to agree and applied for funding ...   Sep 3 2005, 10:18 AM
- - The Messenger   Richard's proposed test of the Pioneer Anomaly...   Sep 3 2005, 05:00 PM
- - Richard Trigaux   Messenger, my idea was intended to detect a gravi...   Sep 4 2005, 07:03 AM
- - Richard Trigaux   The LISA observatory project will use three test m...   Sep 5 2005, 08:57 AM
- - The Messenger   All of these approaches use assumptions we should ...   Sep 5 2005, 04:28 PM
|- - jamescanvin   Heading off topic but... QUOTE (The Messenger ...   Sep 6 2005, 12:17 AM
|- - The Messenger   QUOTE (jamescanvin @ Sep 5 2005, 05:17 PM)Hea...   Sep 6 2005, 05:53 AM
- - Richard Trigaux   Thanks jamescanvin for the image and the info it c...   Sep 6 2005, 06:37 AM
|- - jamescanvin   QUOTE (Richard Trigaux @ Sep 6 2005, 04:37 PM...   Sep 7 2005, 12:27 AM
|- - Richard Trigaux   QUOTE (jamescanvin @ Sep 7 2005, 12:27 AM)Yes...   Sep 7 2005, 05:42 AM
- - dvandorn   Once again, I'm asking a question that I proba...   Sep 7 2005, 07:36 AM
|- - Richard Trigaux   QUOTE (dvandorn @ Sep 7 2005, 07:36 AM)Does a...   Sep 7 2005, 10:28 AM
|- - The Messenger   QUOTE (Richard Trigaux @ Sep 7 2005, 03:28 AM...   Sep 8 2005, 06:21 PM
|- - Richard Trigaux   QUOTE (The Messenger @ Sep 8 2005, 06:21 PM)I...   Sep 9 2005, 07:21 AM
|- - The Messenger   QUOTE (Richard Trigaux @ Sep 9 2005, 12:21 AM...   Sep 12 2005, 01:49 PM
|- - Richard Trigaux   QUOTE (The Messenger @ Sep 12 2005, 01:49 PM)...   Sep 12 2005, 02:23 PM
|- - The Messenger   QUOTE (Richard Trigaux @ Sep 12 2005, 07:23 A...   Sep 12 2005, 06:56 PM
|- - Richard Trigaux   QUOTE (The Messenger @ Sep 12 2005, 06:56 PM)...   Sep 13 2005, 10:15 AM
|- - ljk4-1   QUOTE (Richard Trigaux @ Sep 13 2005, 05:15 A...   Sep 13 2005, 01:17 PM
- - edstrick   I'd have to check, but I think the Apollo 17 i...   Sep 7 2005, 08:22 AM
|- - Bob Shaw   QUOTE (edstrick @ Sep 7 2005, 09:22 AM)The in...   Sep 7 2005, 09:42 AM
||- - dvandorn   QUOTE (Bob Shaw @ Sep 7 2005, 04:42 AM)Oooh, ...   Sep 7 2005, 06:33 PM
||- - Bob Shaw   QUOTE (dvandorn @ Sep 7 2005, 07:33 PM)Oh, th...   Sep 7 2005, 08:47 PM
|- - dvandorn   QUOTE (edstrick @ Sep 7 2005, 03:22 AM)I...   Sep 7 2005, 06:41 PM
- - edstrick   When the gravimeter was proposed, selected and des...   Sep 7 2005, 10:38 AM
|- - Richard Trigaux   QUOTE (edstrick @ Sep 7 2005, 10:38 AM)When t...   Sep 7 2005, 02:38 PM
- - edstrick   "From what I understand, though, even with th...   Sep 8 2005, 10:49 AM
- - edstrick   It has been hoped that cosmic sources of gravitati...   Sep 9 2005, 07:45 AM
|- - Richard Trigaux   QUOTE (edstrick @ Sep 9 2005, 07:45 AM)As far...   Sep 9 2005, 08:17 AM
- - The Messenger   Suggestions, by anyone, of engineering on this sca...   Sep 13 2005, 04:16 PM
|- - Richard Trigaux   QUOTE (The Messenger @ Sep 13 2005, 04:16 PM)...   Sep 13 2005, 06:06 PM
- - The Messenger   Returning to the Pioneer Anomally: You may or may...   Sep 14 2005, 03:31 PM
|- - Richard Trigaux   Messenger, yes the Earth does have a "gravita...   Sep 14 2005, 03:46 PM
|- - ljk4-1   http://www.issi.unibe.ch/teams/Pioneer/ The Pione...   Oct 3 2005, 04:46 AM
- - edstrick   ljk4-1: "...The Pioneer Explorer Collaboratio...   Oct 3 2005, 07:15 AM
- - Richard Trigaux   Thanks ljk4-1 for your interesting contribution. A...   Oct 3 2005, 08:15 AM
- - deglr6328   sooooo did the planetary soc. get the data or what...   Oct 3 2005, 09:53 AM
|- - elakdawalla   QUOTE (deglr6328 @ Oct 3 2005, 02:53 AM)soooo...   Nov 10 2005, 01:29 AM
|- - ljk4-1   QUOTE (elakdawalla @ Nov 9 2005, 08:29 PM) We...   Nov 10 2005, 02:33 PM
|- - elakdawalla   QUOTE (ljk4-1 @ Nov 10 2005, 07:33 AM)De...   Nov 10 2005, 04:46 PM
- - edstrick   <grin> by "anomaly" I mean an ord...   Oct 3 2005, 09:57 AM
|- - Richard Trigaux   QUOTE (edstrick @ Oct 3 2005, 09:57 AM)<gr...   Oct 3 2005, 12:40 PM
- - edstrick   Aliens?... I thought it was the CIA and FBI.... or...   Oct 4 2005, 06:27 AM
|- - Richard Trigaux   QUOTE (edstrick @ Oct 4 2005, 06:27 AM)Aliens...   Oct 4 2005, 07:37 AM
- - edstrick   You know what the problem is with make-believe par...   Oct 4 2005, 10:51 AM
|- - Richard Trigaux   QUOTE (edstrick @ Oct 4 2005, 10:51 AM)You kn...   Oct 4 2005, 04:41 PM
|- - ljk4-1   Astrophysics, abstract astro-ph/0504367 From: Gary...   Oct 4 2005, 07:35 PM
|- - ljk4-1   Paper: astro-ph/0506281 replaced with revised ve...   Oct 26 2005, 02:08 PM
|- - ljk4-1   Paper (*cross-listing*): gr-qc/0511026 Date: Sun...   Nov 9 2005, 04:32 PM
- - Myran   Calculations using the 'MOND' theory (Modi...   Nov 9 2005, 09:10 PM
- - Richard Trigaux   I wonder if we could do any theory of any kind, ad...   Nov 9 2005, 09:21 PM
- - mike   That's what a theory is.   Nov 9 2005, 09:42 PM
- - Myran   QUOTE Richard Trigaux said: I wonder if we could d...   Nov 10 2005, 05:21 AM
- - lyford   Call me old fashioned, but I am a bit wary of jett...   Nov 10 2005, 06:41 AM
|- - The Messenger   QUOTE (lyford @ Nov 9 2005, 11:41 PM)Call me ...   Nov 10 2005, 04:44 PM
|- - lyford   QUOTE (The Messenger @ Nov 10 2005, 08:44 AM)...   Nov 10 2005, 10:06 PM
|- - ljk4-1   Astrophysics, abstract astro-ph/0505310 From: Mic...   Dec 20 2005, 04:05 PM
|- - ljk4-1   General Relativity and Quantum Cosmology, abstract...   Jan 3 2006, 02:31 AM
|- - tfisher   I just read through the last paper linked. They...   Jan 3 2006, 07:10 AM
|- - ljk4-1   Paper: astro-ph/0504367 Date (v1): Sun, 17 Apr 20...   Jan 4 2006, 06:18 PM
- - tasp   I bet it is not as simple as this, but I will pos...   Jan 5 2006, 04:14 AM
|- - mchan   QUOTE (tasp @ Jan 4 2006, 08:14 PM)Any possib...   Jan 5 2006, 06:06 AM
|- - ugordan   QUOTE (mchan @ Jan 5 2006, 07:06 AM)One probl...   Jan 5 2006, 08:52 AM
|- - Bob Shaw   QUOTE (ugordan @ Jan 5 2006, 09:52 AM)Wasn...   Jan 5 2006, 01:16 PM
|- - ljk4-1   Can New Horizons participate in this experiment? ...   Jan 5 2006, 02:22 PM
|- - djellison   QUOTE (ljk4-1 @ Jan 5 2006, 02:22 PM)Can...   Jan 5 2006, 02:43 PM
|- - ugordan   QUOTE (djellison @ Jan 5 2006, 03:43 PM)That...   Jan 5 2006, 02:50 PM
- - tasp   If an objection to putting a Voyager into a slow s...   Jan 5 2006, 02:45 PM
- - djellison   Damn good point actually UG - hadnt thought of tha...   Jan 5 2006, 02:58 PM
- - ugordan   QUOTE (djellison @ Jan 5 2006, 03:58 PM)Then ...   Jan 5 2006, 03:05 PM
- - NMRguy   QUOTE (Alan Stern @ Feb 23 2005, 09:20 AM)Yes...   Jan 5 2006, 05:19 PM
|- - AlexBlackwell   QUOTE (NMRguy @ Jan 5 2006, 05:19 PM)Alan add...   Jan 5 2006, 05:56 PM
- - tty   QUOTE (ugordan @ Jan 5 2006, 05:05 PM)Might h...   Jan 5 2006, 06:47 PM
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