Pioneer 10/11 Dragging Their Feet

What could be slowing down Pioneer 10 and 11? Could it be that our understanding of physics as it relates to space is wrong in some subtle way?

Strange doings on the edge of the solar system.

Something strange is happening in the outer reaches of our solar system. The Pioneer 10 and 11 spacecraft are not where they are supposed to be. These missions, launched in 1972 and 1973, have covered hundreds of millions of kilometers, heading toward the edge of our solar system. But something is holding them back. Each year, they fall behind in their projected travel by about 5,000 kilometers (3,000 miles).
Jet Propulsion Laboratory scientist John Anderson and his colleagues have been searching for an explanation since 1980. But as of yet, they have found nothing conclusive; no spacecraft behavior or previously unknown property of the outer solar system can explain the deceleration of the Pioneer spacecraft. Scientists are being forced to consider the unthinkable: something may be wrong with our understanding of the laws of physics. An important line of inquiry will be to study mounds of Doppler (velocity) data and spacecraft status data (like temperatures) that have been unavailable to researchers—but that is about to change.


LINK

grammar edit

[edit on 24/2/07 by masqua]

I was only reading about this myself not a day or two ago. This to me is absolutely fascinating! Pioneer is getting real close to the heliosphere and I have a feeling it may come to a halt! Heres a pretty hardcore discussion on this, many ideas on why but nothing can be for sure until they send another probe or 50 that dont use thruster-stabilizers and see what happens.

TABLE II: Error Budget: A Summary of Biases and Uncertainties.

Item Description of error budget constituents
1 Systematics generated external to the spacecraft:
.. .. a) Solar radiation pressure and mass
.. .. b) Solar wind
.. .. c) Solar corona
.. .. d) Electro-magnetic Lorentz forces
.. .. e) Influence of the Kuiper belt’s gravity
.. .. f) Influence of the Earth orientation
.. .. g) Mechanical and phase stability of DSN antennae
.. .. h) Phase stability and clocks
.. .. i) DSN station location
.. .. j) Troposphere and ionosphere

2 On-board generated systematics:
.. .. a) Radio beam reaction force
.. .. b) RTG heat reflected off the craft
.. .. c) Differential emissivity of the RTGs
.. .. d) Non-isotropic radiative cooling of the spacecraft
.. .. e) Expelled Helium produced within the RTGs
.. .. f) Gas leakage
.. .. g) Variation between spacecraft determinations

3 Computational systematics:
.. .. a) Numerical stability of least-squares estimation
.. .. b) Accuracy of consistency/model tests
.. .. c) Mismodeling of maneuvers
.. .. d) Mismodeling of the solar corona
.. .. e) Annual/diurnal terms

Electric Universe theory reckons it has solved the mystery.

here's a good graphic, showing different crafts (pioneers, voyagers..)
and their location & direction in relation to 'Sol'
www.heavens-above.com...


i think it, the slowing of the craft, has to do with the Termination Shock Wave that builds up at the edge of the Heliosphere where the solar wind
rapidly slows to subsonic speed as it encounters particles and fields that make up the Local Interstellar Medium...there are some illustrations here;

spacephysics.ucr.edu.../sw/swq6.html


*[this (shock)wave, is nothing to do with the 'tsunami' wave from space, that others are talking about]*




[edit on 24-2-2007 by St Udio]

Really cool topic!!



Ok so they cannot confirm the same anomaly on either of the Voyager craft because the Voyager craft seem to be thruster stabilised and that supposedly complicates the effect of the solar winds.
Having said that, this is NOT happening on either of the Voyager craft, and infact V2 is around 10 AU further out than P10.

Now another point:

The Sun is moving in an elliptic orbit oscillating about the galactic plane.Hence I presume the types of forces on the termination shock, HelioPause and bowshock would be considerably different at the advancing front up ahead as compared to the receding front at the back.

V2 and P10 have a angular separation of ~130Deg(no need for a solid angle as both trajectories are approximately in one plane). So if we could determine whether one is progressing to the advancing or receding front, then maybe this would introduce another important factoring component.
Also notably P10 shares a similar angular separation with all other probes(V1,P11,V2).

Is there something inherently different about the front P10 is advancing toward?How is wish P11 was still active!! Data from P11 would answer most of these Qs straight off!!

Great link on current probe positions St Udio

Just a confirmation:
Tel,Oph and Sct constellations stand for Telescopium,Ophiucus and Scutum aye?
Just did a brief google for this and have never of these constellations before so confirming!



[edit on 24-2-2007 by Daedalus3]

Originally posted by Daedalus3
Ok so they cannot confirm the same anomaly on either of the Voyager craft because the Voyager craft seem to be thruster stabilised and that supposedly complicates the effect of the solar winds.
Having said that, this is NOT happening on either of the Voyager craft, and infact V2 is around 10 AU further out than P10.

Yup, to reiterate, all the voyagers use thruster-stablizers whereas P 10 and 11 do not have them. Its been pretty much accepted that it is the reason for the pull back towards the sun, not enough forward push to compensate for the anomalous pull. So comparing with the other probes is a moot point unfortunately.

Is there something inherently different about the front P10 is advancing toward?How is wish P11 was still active!! Data from P11 would answer most of these Qs straight off!!

Isnt is a crying shame! We need to send more probes out asap. We need to know!!

V2 is the furthest from the sun but I wonder which probe is actually closer to the heliosphere.

^^
Ah you mean to say that one may be heading along the major axis of the heliosphere ellipse and the other minor?
hmmm...

For example, the spiral arms of a galaxy must carry the electric current that lights the stars.

That's the sentence in the "Electric Universe" theory that puzzled me. What exactly do they mean by that ?

Interstellar winds may act as a source of flowing energy(just like electrons in electricity?) and when they impact a star system's electro/magnetic/gravitational boundary, they pass on this energy to the star.
I suppose the general direction of the winds could be from the inward spiral to the outward side. That could explain how the star density reduces as you move out from the galactic center.
Now whether these winds actually assist in the nuclear fusion within a star or just cause variations in the general macroscopic electromagnetic galactic scene is another thing.

^^Just my plausible interprtation of this theory. Haven't read anything about the theory though!