≡ Menu

Reconstructing the Pioneer Anomaly

New Scientist is running an interesting piece [subscription required for full access] on Slava Turyshev (JPL), who plans to investigate the so-called Pioneer Anomaly by re-flying the mission virtually. It’s a fascinating tale for various reasons, not the least of which is how close we came to losing much if not all of the precious Pioneer data. For one thing, 400 reels of magnetic tapes housing information about the trajectories of the two spacecraft had to be saved from years of neglect and transferred to DVD.

And that was just the beginning. When Turyshev visited NASA’s Ames Research Center, his search for project records from the 114 onboard sensors that recorded the Pioneers’ spin rate and other data turned up the floppy disks that mission engineer Larry Kellogg had saved. But Ames managers were close to destroying the disks because of lack of space. Having interceded to save this material, Turyshev then turned to programmer Viktor Toth to write a program to extract 40 gigabytes of data from the old floppies, to be recorded like the tapes onto DVD.

So now we can re-fly the missions, correlating each spacecraft event with tracking data in hopes of finding something that might tell us why Pioneer 10, when last heard from, was off-course by about 400,000 kilometers, and why its sister spacecraft is also not quite where it ought to be. A new challenge for Einsteinian gravity, or an effect created within the spacecraft themselves? Prime candidates for scrutiny are the radioisotope thermoelectric generators (RTGs) that power the Pioneers, and the possibility that their waste heat could raise the temperature of one side of the spacecraft, producing a tiny thrust.

The data should tell us whether we can rule out onboard effects and start contemplating a tweak to current gravitational theories. Such a tweak seems unlikely to Centauri Dreams given the lack of evidence of any such effect on other objects in the outer Solar System, but the investigation is well worth making, and could be further developed in a future space mission. On that score, be aware of Dario Izzo (European Space Agency), whose paper “Options for a nondedicated mission to test the Pioneer anomaly,” written with Andreas Rathke and scheduled to appear in the Journal of Spacecraft and Rockets, is available here.

And get this comment from Izzo on the size of the malfunction (if it exists) aboard the Pioneers: “The leak of a single molecule of gas from the spacecraft will give a momentary acceleration similar in size to the Pioneer anomaly.” That’s not much to work with, but as New Scientist writer Stuart Clark points out, the force acting on the spacecraft is a persistent one, so any malfunction would have to be similarly long-lived. The article is “Have We Got Gravity All Wrong?” in the magazine’s June 3 issue.

Comments on this entry are closed.

  • tibor June 5, 2006, 15:14

    It may be interesting to note that dedicated mission concepts are also studied. Two of them are available at http://arxiv.org/abs/gr-qc/0205059 and http://arxiv.org/abs/gr-qc/0506139, respectively. One obstacle against dedicated missions is the expected high costs.

  • Administrator June 5, 2006, 15:21

    A good point, and a dedicated mission would surely be preferable if money could be found. But I suspect it will be hard to make the case for a dedicated mission without some evidence of related anomalies in the orbits of other outer system objects. Wouldn’t it be grand, though, if our ancient Pioneers had given us one last discovery? Thank goodness the data were preserved!

  • nduriri August 11, 2006, 16:52

    Dear Sir,
    I have now solved the pioneer anomaly and also other 5 cosmological blunders of the last 85 years, see the summary page 8, new Newton law page 1, http://www.gravitomagnetism.com
    Joseph Nduriri ++33(0)6-31-13-61-55

  • nduriri August 24, 2006, 2:14

    Allais Effect has been solved

    1) The pioneer anomaly (hidden matter)
    2) The Allais Effect (gravity shield)
    3) The galaxy disk shape flatness (no explanation).
    4) The spiral form aspiration of matter by the accretion disk (frame dragging, science fiction).
    5) The matter bipolar jets trajectory (magneto hydrodynamics theory, incoherent theory since the magnetic field cannot deflect neutral matter = circumstantial theory = confusion).
    6) Galaxy rotation curve flatness (dark matter, MOND theory).
    7) The source of matter bipolar jets (contradicts event horizon theory, science fiction)
    See summary page 9 and page 1 for new Newton law

  • nduriri September 23, 2006, 13:27

    By using the light dynamics, the radiation pressure for any reflective surface can be derived. By using the same approach the light rocket engine thrust equation can be derived.
    See light dynamics.PDF http://www.gravitomagnetism.com

  • nduriri November 18, 2006, 16:43

    Dear Friend,
    Thanks alot for your comments in the forum, I done pretend to be right. I have now define the Earth dipole gravitational radiation. Please see topic: New Newton and gravitaional radiation page 5 http://www.gravitomagnetism.com
    Please tell your friends and advise.
    My kindest regards. I love physics.
    Joseph NDURIRI
    89 avenue Crampel
    Appt 11
    31400 Toulouse France

  • nduriri December 1, 2006, 2:30

    Since the gravitomagnetic force component Fg is not radial, it exerts a moment of force on the two-body system. This moment of force is negative during half cycle A and positive during half cycle B. This moment of force induces a negative rate of change of momentum known as torque during half cycle A and positive one during half cycle B. Thus an alternating torque, hence an alternating rate of change of angular momentum of the two-body system. There is no conservation of angular momentum as stated by the Newton law. The positive moment of force is always greater than the negative one. This explains the mercury perihelion advance. For more details see gravitational waves radiation http://www.gravitomagnetism.com

  • ljk January 4, 2007, 13:35

    General Relativity and Quantum Cosmology, abstract

    From: Marc Lachieze-Rey [view email] [via CCSD proxy]

    Date: Tue, 2 Jan 2007 16:00:09 GMT (8kb)

    Cosmology in the Solar System: Pioneer effect is not cosmological

    Authors: Marc Lachieze-Rey (APC)

    Does the Solar System and, more generally, a gravitationally bound system follow the cosmic expansion law ? Is there a cosmological influence on the dynamics or optics in such systems ? The general relativity theory provides an unique and unambiguous answer, as a solution of Einstein equations with local sources (e.g., the Sun), and with the correct (cosmological) limiting conditions. This solution has no analytic expression. A Taylor development of its metric allows a complete treatment of dynamics and optics in gravitationally bound systems, up to the size of galaxy clusters, taking into account both local and cosmological effects. In the solar System, this provides an estimation of the (non zero) cosmological influence on the Pioneer probe: it fails to account for the ” Pioneer effect ” by about 10 orders of magnitude. We criticize contradictory claims on this topic.


  • ljk February 6, 2007, 12:59

    General Relativity and Quantum Cosmology, abstract

    From: Lorenzo Iorio [view email]

    Date (v1): Wed, 23 Aug 2006 09:38:51 GMT (17kb)
    Date (revised v2): Thu, 7 Sep 2006 22:13:14 GMT (17kb)
    Date (revised v3): Tue, 9 Jan 2007 22:44:26 GMT (17kb)
    Date (revised v4): Sat, 3 Feb 2007 00:19:36 GMT (19kb)

    The Lense-Thirring effect and the Pioneer anomaly: Solar System tests

    Authors: Lorenzo Iorio

    Comments: WS LaTex macros for proceedings, 3 pages, no figures, no tables, 31 references. Paper submitted to the Eleventh Marcel Grossmann Meeting on General Relativity, 23-29 July, Freie Universitaet Berlin, 2006. Abridged version to meet page limits. Some changes in the Lense-Thirrings section including the new results from MGS. Thanks to Daniela Taeuber for useful correspondence about the Pioneer anomaly

    Subj-class: General Relativity and Quantum Cosmology; Geophysics; Space Physics

    We report on a \lessim 1% test of the Lense-Thirring effect with the Mars Global Surveyor (MGS) spacecraft and on certain features of motion of Uranus, Neptune and Pluto which contradict the hypothesis that the Pioneer anomaly can be caused by some gravitational mechanism.


  • nduriri February 26, 2007, 5:53

    By using relativity, gravity waves have quantitatively been determined during the solar eclipse. The gravity waves are induce at a supersonic speed (1000m/s), they induce gravitomotive force g.m.f. in gases and liquids, thereby creating masse currents which is converted into sound waves; they also induce electromotive force e.m.f. in electric conductors, plasma, ionosphere and metals thereby creating electric currents.
    Since the quasi stationary orthodox gravity shield theories do not offer a global and coherent explanation concerning gravity perturbations, can there be a physical science work of more importance than obtaining an understanding of these perturbations and seeking interaction with the remote forces of gravity?
    The facts are there, the facts remain the keystone in which the stability of a theory must be tested.
    See http://www.gravitomagnetism.com
    Joseph Nduriri, Paris, FRANCE

  • ljk June 27, 2007, 10:12

    Exotic cause of ‘Pioneer anomaly’ in doubt

    08:00 22 June 2007

    NewScientist.com news service

    David Shiga

    The ‘Pioneer anomaly’ – the mystifying observation that NASA’s two Pioneer spacecraft have drifted far off their expected paths – cannot be explained by tinkering with the law of gravity, a new study concludes.

    The study’s author suggests an unknown, but conventional, force is instead acting on the spacecraft. But others say even more radical changes to the laws of physics could explain the phenomenon.

    Launched in the early 1970s, NASA’s Pioneer 10 and 11 spacecraft are drifting out of the solar system in opposite directions, gradually slowing down as the Sun’s gravity pulls back on them.

    But they are slowing down slightly more than expected and no one knows why. Some physicists say the law of gravity itself needs revising, so that gravity retains more strength in the outer solar system. But there has been disagreement about whether such modifications would accurately predict the orbits of the outer planets.

    Now, Kjell Tangen, a physicist at the firm DNV in Hovik, Norway, says tweaking the law of gravity in a variety of ways cannot explain the anomaly – while also getting the orbits of the outer planets right. After modifying gravity in ways that would match the Pioneer anomaly, he inevitably got wrong answers for the motion of Uranus and Pluto.

    Full article here: