Re: Pioneer Anomoly



John C. Polasek wrote:
> On Sat, 25 Jun 2005 08:17:08 +0100, "George Dishman"
> <george@xxxxxxxxxxxxxxxxx> wrote:
> >"John C. Polasek" <jpolasek@xxxxxxxxxx> wrote in message
> >news:9hgpb1h9g61udsomekoic1di33ambnaqsi@xxxxxxxxxx
> >> On Fri, 24 Jun 2005 15:05:34 +0100, "George Dishman"
> >> <george@xxxxxxxxxxxxxxxxx> wrote:
> >>>"John C. Polasek" <jpolasek@xxxxxxxxxx> wrote in message
> >>>news:krnmb1hq717rutfupoctgc5j20teqi8tfm@xxxxxxxxxx
....
> >> I agree, with the transponder the doppler would be double the value.
> >> Unfortunately that also takes out any effect the gravitational field
> >> would have on the Pioneer clock. That is very probably where the
> >> secret is. Do you agree that gravitational effects woud be washed out?
> >
> >It cancels out the effect of the difference
> >in gravitational potential on the frequency
> >but doubles the Doppler due to the motion
> >of the craft. All sources of acceleration
> >still affect the motion of the craft and
> >hence the received frequency.
> >
> Not much to add except that between an Anderson, Turyshev and
> Markwardt there is evidence that using clock drift models, the Doppler
> was well modeled, but ranging was not. I conclude from that that the
> craft does not really decelerate.

That's the wrong way round. What they are saying
is that if you make a model in which the frequency
is directly affected rather than as a result of
motion, the distance is a poorer fit.

> The effect appears to be strictly in
> the clock arithmetic.

No, it appears that it is more likely that
the acceleration has really displaced the
craft (by 1/2 a t^2) but without the
dedicated ranging system, they cannot be
sure and both possibilities are still being
considered.

> It is hard to figure out since to simply the problem, the vehicle does
> not need to be moving at all, just accelerating.

If you cancel out all the other factors,
that is what is left. However, you have to
be very accurate in predicting the values
to subtract. Try doing those little sums I
suggestd to understand the difficulty. You
might also then be able to compare the
magnitude of the anomaly to the difference
between your theory and GR.

> Also it seems to me
> that's the same as putting the base xmtr right on the craft when as
> one paper says, the S-band signals were actively reflected
> (phase-locked) by a transponder on the craft.

It is equivalent to a perfect transmitter on
the craft other than the factor of two discussed
above.

> Another thing I noticed is that the polarity is sometimes backward,
> probably due to not affixing a minus sign to Ap. The acknowledge in a
> footnote.

The DSN convention is the opposite of what
everyone expects and has caused some
confusion. The clear statement is that the
acceleration appears to be towards the Sun,
not away from it. Markwardt also checked and
confirmed that.

> They use the formula
> fobs = fmodel(1 + A;*t/c)
> which implies a 1-way Doppler, contrary to your claim of 2--way,
> unless I have it wrong. Is fmodel the drift on the craft? It's phase
> locked.

They sometimes state the one-way formula and
then double it when using the result. All the
data was transponded, mostly what the call
"three-way" (using different ground stations)
but there may have been some "two-way" (same
ground station for tx and rx). I think you
will find statements saying the one-way data
was discarded in both papers. (I can't check
at the moment.)

> I am still working on it.

It isn't trivial !

Good luck
george

.

Relevant Pages

  • Re: Pioneer Anomoly
    ... >>>of the craft. ... >> Markwardt there is evidence that using clock drift models, the Doppler ... I think if the anomaly were due to real acceleration, ...
    (sci.astro)
  • Re: P10 Doppler,11.5 hours or a few seconds?
    ... the light travel time varies smoothly with time. ... >> estimating the solar plasma noise from the Doppler data, ... > apparent acceleration of P10 toward the earth and the sun is much ... > the sun craft line and the Madrid craft line would produce with the ...
    (sci.astro)
  • Re: Pioneer Anomoly
    ... >>>Suppose the craft is moving away from Earth. ... There is another Doppler red shift on the ...
    (sci.astro)
  • Re: Pioneer 10 test of light speed delay
    ... > The ephemeris of the craft is what is to be determined. ... > means we don't know the motion of the Earth relative to ... > isn't necessary as it's only the projection onto the ... a constant acceleration would change the ...
    (sci.astro)
  • Re: Inertial-dampening systems
    ... > Aside from field propagation time, ... > Consider the view of a disc-shaped craft, ... > acceleration of the craft in the plane of its diameter, ... > upon the cabin occupants, ...
    (sci.physics)