Could Dust Be Responsible for the Pioneer Anomaly?

[SJGooch]

I have looked through the on-line documentation of the Pioneer Anomaly, and have a simple question:

Could the apparent additional acceleration toward the Sun be due to an additional mass of dust which adhered to the spacecraft ?

I notice that the authors of the main papers ( http://arxiv.org/PS_cache/gr-qc/pdf/0512/0512121v2.pdf ) claim to have considered the possibility of dust as a cause. But the only references I can find regarding dust are related to gravitational effects in which the spacecraft s are gravitationally attracted to large dust clouds. Not effects in which additional mass is added to the spacecraft by adhering dust particles.

In a similar vein, could some part of the outer skin of the spacecraft react with the solar wind, trapping hydrogen (for example) as part of a chemical compound?

There appears to be no treatment of how little the actual mass of a spacecraft would have to deviate from its accepted mass for the "anomalous" additional attraction to the sun to be observed. The observed effect is exceedingly small, so I suspect very little dust would be required.

Additional force of attraction to the sun due to additional mass of the spacecraft could be ruled out by measuring the ratio of inertial mass of the spacecraft to its gravitational mass. I.e. late in the mission, does the modification of the spacecraft 's velocity as it passes near a massive object verify the supposed mass of the spacecraft ?

Is there some obvious reason, that I have missed, that this slight additional deceleration due to solar gravity cannot be due to a slight increase in the mass of the spacecraft ?

Thank you for your attention.

 

[Kracatoan]

It seems like a pretty decent hypothesis about the anomaly. Working out how much dust would be needed is beyond me, I would be interested to see if someone else here could work it out, which I expect they could.

My only concern would be that it might be difficult for the dust to adhere to the probe, perhaps due to materials used and high velocities of both probe and dust, seeing as I very much doubt they would be moving in the same direction with similar speeds which would make it easy for dust to adhere.