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Ranging and Pioneer
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Spud
science forum beginner


Joined: 30 May 2005
Posts: 47

PostPosted: Mon Jul 03, 2006 12:29 am    Post subject: Re: Ranging and Pioneer Reply with quote

Oh No wrote:
Quote:
The position of Pioneer was calculated from Doppler information. Ranging
was not available. Can anyone explain why ranging could not be used? Is
this just a limit on available technology, or is there a more
fundamental reason?

gr-qc/0104064

Spud
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Oh No
science forum addict


Joined: 06 Apr 2006
Posts: 82

PostPosted: Mon Jul 03, 2006 12:13 pm    Post subject: Re: Ranging and Pioneer Reply with quote

Thus spake Spud <omeganumber@yahoo.co.uk>
Quote:

Oh No wrote:
The position of Pioneer was calculated from Doppler information. Ranging
was not available. Can anyone explain why ranging could not be used? Is
this just a limit on available technology, or is there a more
fundamental reason?

gr-qc/0104064

Many thanks. If I understand Anderson correctly it is merely an

engineering constraint. With a (perhaps greatly) amplified signal it
should be possible to reduce integration times to achieve correlation so
that the signal can be returned without a substantial range delay.
Anyway that is the basis on which I am working at the moment.

But I am not an engineer, and I was hoping this might be confirmed. My
arguments would take quite a different form if this was a fundamental
constraint.




Regards

--
Charles Francis
substitute charles for NotI to email
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Uncle Al
science forum Guru


Joined: 24 Mar 2005
Posts: 1226

PostPosted: Tue Jul 04, 2006 3:57 am    Post subject: Re: Ranging and Pioneer Reply with quote

Oh No wrote:
Quote:

Thus spake Spud <omeganumber@yahoo.co.uk

Oh No wrote:
The position of Pioneer was calculated from Doppler information. Ranging
was not available. Can anyone explain why ranging could not be used? Is
this just a limit on available technology, or is there a more
fundamental reason?

gr-qc/0104064

Many thanks. If I understand Anderson correctly it is merely an
engineering constraint. With a (perhaps greatly) amplified signal it
should be possible to reduce integration times to achieve correlation so
that the signal can be returned without a substantial range delay.
Anyway that is the basis on which I am working at the moment.

But I am not an engineer, and I was hoping this might be confirmed. My
arguments would take quite a different form if this was a fundamental
constraint.

http://arxiv.org/abs/gr-qc/0205059
Pioneer anomaly
http://arXiv.org/abs/gr-qc/0307042
Rationalized Pioneer anomaly
http://arXiv.org/abs/gr-qc/9810085
Believable rationalized Pioneer anomaly
http://arXiv.org/abs/gr-qc/gr-qc/0310088
Believable Pioneer anomaly updated
http://www.arxiv.org/abs/gr-qc/0411020
Pioneer anomaly
http://arXiv.org/abs/physics/0502123
Commentary on Pioneer anomaly minutia
http://arXiv.org/abs/gr-qc/0506139
http://math.ucr.edu/home/baez/open.questions.html

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Richard Saam
science forum Guru Wannabe


Joined: 20 May 2005
Posts: 137

PostPosted: Wed Jul 05, 2006 3:18 am    Post subject: Re: Ranging and Pioneer Reply with quote

Oh No wrote:

Quote:
The position of Pioneer was calculated from Doppler information. Ranging
was not available. Can anyone explain why ranging could not be used? Is
this just a limit on available technology, or is there a more
fundamental reason?


Regards


Here is an extreme case
in terms of Beta Pictoris
at many light years distance

arXiv:astro-ph/0601244 v1 11 Jan 2006

Dynamic motions are inferred from
atomic molecular quantum transitions.

The time (frequency) of such transitions are assumed the same
there and here
from which observed differences in frequencies
are related to dynamic motions.

The problem is the same as you identify.
How does one "range" the motions of Asteroid size objects
(which do not have quantum transitions) in Beta Pictoris
other than observing the gross newtonian gravity motions of the system
as a whole.

The problem could be solved if only a radar signal could be sent,
reflected for obtaining active ranging information.

Such a procedure is performed with the earth's moon
which is aided by a corner reflector positioned there.
Moon position is ranged from earth within centimeters.

Could such a ranging procedure be conducted
on a Pioneer size object at > 10 AU.
If so, then a dedicated spacecraft mission would not be necessary.
One would only have track various objects
of Pioneer size and smaller that are at > 10 AU.
(area to mass ratio may be a very important parameter)

Such questions are important.
It could be the reason that our solar system is essentially dust free
at 5 billion years old
and Beta Pictoris has lots of dust at ~10 million years old.

Richard
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Spud
science forum beginner


Joined: 30 May 2005
Posts: 47

PostPosted: Wed Jul 05, 2006 3:18 am    Post subject: Re: Ranging and Pioneer Reply with quote

Oh No wrote:
Quote:
The position of Pioneer was calculated from Doppler information. Ranging
was not available. Can anyone explain why ranging could not be used? Is
this just a limit on available technology, or is there a more
fundamental reason?

Interesting

astro-ph/0501626

Spud
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Nanook
science forum beginner


Joined: 08 Jul 2006
Posts: 1

PostPosted: Sat Jul 08, 2006 2:37 pm    Post subject: Re: Ranging and Pioneer Reply with quote

In article <1151862325.211802.139320@a14g2000cwb.googlegroups.com>, Spud <omeganumber@yahoo.co.uk> writes:
Quote:

Oh No wrote:
The position of Pioneer was calculated from Doppler information. Ranging
was not available. Can anyone explain why ranging could not be used? Is
this just a limit on available technology, or is there a more
fundamental reason?

gr-qc/0104064

Spud

Just wanted to ask something about this. In order to measure Doppler
shift, you need to measure frequency accurately right? And in order to
measure frequency accurately you have to have an accurate clock.

I founded an IRC network (Newnet Internet Relay Chat). We had a problem
with servers being out of sync, clocks didn't agree.

Part of our network was using national institute of standards and
technologies NIST time server, others were using a time server at Nasa.

The root of the problem turned out that NASA's time server was about
five seconds off of NIST's.

Now I thought NIST was supposed to be THE gold standard, which would
mean that NASA's clock is off. And if NASA's clock isn't accurate, then by
extension neither is the precise measure of frequency and thus Doppler shift.

So I can't help but wonder while we're re-writing the laws of
cosmology on the basis of the unexpected Doppler shift of Pioneer I and II,
if we might be really doing so on the basis of an incorrectly calibrated
clock at NASA.

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Aidan Karley
science forum beginner


Joined: 02 Jun 2005
Posts: 18

PostPosted: Tue Jul 11, 2006 4:35 pm    Post subject: Re: Ranging and Pioneer Reply with quote

In article <e8lbpj$4fj$1@eskinews.eskimo.com>, Nanook wrote:
Quote:
Part of our network was using national institute of standards and
technologies NIST time server, others were using a time server at Nasa.

The root of the problem turned out that NASA's time server was about
five seconds off of NIST's.

Now I thought NIST was supposed to be THE gold standard, which would
mean that NASA's clock is off. And if NASA's clock isn't accurate, then by
extension neither is the precise measure of frequency and thus Doppler shift.

I was under the impression that the "gold standard" for time is a

collaborative thing between a number of national and international time
services, not tied to any one machine or even site.
A five *second* difference between clocks that are meant to be accurate
to microseconds per year/ millennium (I can't remember which) I don't think is
credible. More credible would be that your network topology either had some
sort of horrible delay-inducing asymmetric loop in it to one of the time
sources, or that you were asking the wrong questions of one of the machines.
E.g., getting time according to UTC from one machine, but something corrected
to local noon from the other (that would give time differences of up to several
minutes a day, if I remember my horology correctly, but variable at different
times of the year).

--
Aidan Karley, FGS
Aberdeen, Scotland
Written at Tue, 11 Jul 2006 03:13 +0100, but posted later.
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Spud
science forum beginner


Joined: 30 May 2005
Posts: 47

PostPosted: Tue Jul 11, 2006 4:35 pm    Post subject: Re: Ranging and Pioneer Reply with quote

Nanook wrote:

Quote:
Just wanted to ask something about this. In order to measure Doppler
shift, you need to measure frequency accurately right? And in order to
measure frequency accurately you have to have an accurate clock.

I founded an IRC network (Newnet Internet Relay Chat). We had a problem
with servers being out of sync, clocks didn't agree.

Part of our network was using national institute of standards and
technologies NIST time server, others were using a time server at Nasa.

The root of the problem turned out that NASA's time server was about
five seconds off of NIST's.

Now I thought NIST was supposed to be THE gold standard, which would
mean that NASA's clock is off. And if NASA's clock isn't accurate, then by
extension neither is the precise measure of frequency and thus Doppler shift.

So I can't help but wonder while we're re-writing the laws of
cosmology on the basis of the unexpected Doppler shift of Pioneer I and II,
if we might be really doing so on the basis of an incorrectly calibrated
clock at NASA.

There may have been a clash of using different server config files
causing the problem.

The DSN uses its own time server.

See page 13 http://hdl.handle.net/2014/39083

Spud
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David M. Palmer
science forum beginner


Joined: 19 Jun 2005
Posts: 16

PostPosted: Wed Jul 12, 2006 4:05 am    Post subject: Re: Ranging and Pioneer Reply with quote

In article <e8lbpj$4fj$1@eskinews.eskimo.com>, Nanook
<nanook@eskimo.com> wrote:

Quote:
The root of the problem turned out that NASA's time server was about
five seconds off of NIST's.

Now I thought NIST was supposed to be THE gold standard, which would
mean that NASA's clock is off. And if NASA's clock isn't accurate, then by
extension neither is the precise measure of frequency and thus Doppler shift.


NASA is a big organization. They don't have 'a clock'.

Are the timeservers you were using supposed to be public timeservers?
What stratum are they? If you are setting up a large IRC network, you
shouldn't be hitting high level time servers. Get one of your machines
to be the only one to contact a good server (or some other source like
a cheap GPS clock) and have others contact that machine.

Anyway, when I got to my current job, I pointed my NTP client at
time.where.I.work , which worked as an NTP server. When I noticed that
the time on my computer was way off, I tracked down the owner of that
machine. He didn't know his computer's NTP server port was active, he
just had a desktop computer named 'time' and a laptop named 'space'.

So anyway, it is unlikely that the Pioneer anomaly is due to an
inaccurate NTP server.

--
David M. Palmer dmpalmer@email.com (formerly @clark.net, @ematic.com)
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Aidan Karley
science forum beginner


Joined: 02 Jun 2005
Posts: 18

PostPosted: Wed Jul 12, 2006 2:28 pm    Post subject: Re: Ranging and Pioneer Reply with quote

In article <110720062035087637%dmpalmer@email.com>, David M. Palmer
wrote:
Quote:
So anyway, it is unlikely that the Pioneer anomaly is due to an
inaccurate NTP server.

Doesn't the Pioneer anomaly predate the development of NTP

anyway?

--
Aidan Karley, FGS
Aberdeen, Scotland
Written at Wed, 12 Jul 2006 09:30 +0100, but posted later.
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John Bell
science forum addict


Joined: 31 Dec 2005
Posts: 84

PostPosted: Mon Jul 17, 2006 3:32 pm    Post subject: Re: Ranging and Pioneer Reply with quote

Oh No wrote:
Quote:
The position of Pioneer was calculated from Doppler information.

This statement is misleading. The position(s) of Pioneer(s) at any
given time was calculated using classical trajectory dynamics (with GR
corrections taken into account). So was the anticipated velocity hence
Doppler shift of antenna signal at any given time. What was observed by
NASA/JPL was an accumulating deviation from predicted Doppler shift,
which led Anderson et al. to infer an apparent classically anomalous
acceleration of the probes.

These apparent classically anomalous accelerations were tabulated
against predicted positions, not against altered positions inferred
from such apparent classically anomalous accelerations of the probes.

John (Liberty) Bell
http://global.accelerators.co.uk
(Change John to Liberty to respond by email)
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Richard Saam
science forum Guru Wannabe


Joined: 20 May 2005
Posts: 137

PostPosted: Mon Jul 17, 2006 3:32 pm    Post subject: Re: Ranging and Pioneer Reply with quote

Oh No wrote:

Quote:
The position of Pioneer was calculated from Doppler information. Ranging
was not available. Can anyone explain why ranging could not be used? Is
this just a limit on available technology, or is there a more
fundamental reason?


Regards

The following reference provides a mission

to quantify the anomalous effect with ranging capability:

ref1:A MISSION TO EXPLORE THE PIONEER ANOMALY
H. Dittus, S.G. Turyshev, J.D. Anderson et al
http://arxiv.org/pdf/gr-qc/0506139
3.3. A Dedicated Mission Concept

Quote
"In particular,
we emphasize a precision formation flying as a feasible
flight system concept for the proposed mission. For
this architecture, a passive sphere covered with cornercube
retroreflectors is laser-ranged from the primary craft."
Unquote

This is an excellent idea.
My fear is that 'area to mass' ratio
will not be designed into the "passive sphere"

If the "passive sphere" is designed
as a bowling ball rather than a soccer ball
the anomalous deceleration effect will not be measured above the noise.

Why not have several passive objects
with an array of geometric shapes (Platonic solids for a start)
with a range of 'area to mass' ratios
all fitted with cornercube retroreflectors
and ranged from the primary craft.

Ref2:
Seconds of Data, Years of Trying
Photonics Spectra, May 2006 Vol 40, Issue 5, p 56

This reference provides a good perspective
on capability of detecting laser space ranging data
within the context of receiving ranging information from the
Messenger Mission to Mercury.
After much effort, the distance
to the Laser Altimeter Instrument
on the Messenger Mission to Mercury
was measured at 23,964,675,433.9 +/- .2 m.
(14,890,958.9 statute miles)
(~.16 AU)

Ref1 would appear to be the only reasonable approach
for ranging small distant (from earth) space object trajectories

Richard Saam
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John Bell
science forum addict


Joined: 31 Dec 2005
Posts: 84

PostPosted: Mon Jul 17, 2006 3:32 pm    Post subject: Re: Ranging and Pioneer Reply with quote

Richard Saam wrote:
Quote:
Oh No wrote:

The position of Pioneer was calculated from Doppler information. Ranging
was not available. Can anyone explain why ranging could not be used? Is
this just a limit on available technology, or is there a more
fundamental reason?


Regards


Here is an extreme case
in terms of Beta Pictoris
at many light years distance

arXiv:astro-ph/0601244 v1 11 Jan 2006

Dynamic motions are inferred from
atomic molecular quantum transitions.

The time (frequency) of such transitions are assumed the same
there and here
from which observed differences in frequencies
are related to dynamic motions.

The problem is the same as you identify.
How does one "range" the motions of Asteroid size objects
(which do not have quantum transitions) in Beta Pictoris
other than observing the gross newtonian gravity motions of the system
as a whole.

The problem could be solved if only a radar signal could be sent,
reflected for obtaining active ranging information.

In fact, with the (still functional) Pioneer, the possibility of
obtaining ranging data is enhanced by the fact that it contains a
narrow beam broadcast antenna directed towards the Earth, which can be
turned on and off via ground control.

Whether or not NASA thought to accuirately design and measure such turn
on/off delays prior to launch, in order to facilitate such a ranging
test, is, of course, another matter.

John (Liberty) Bell
http://global.accelerators.co.uk
(Change John to Liberty to respond by email)
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Jonathan Silverlight
science forum addict


Joined: 06 May 2005
Posts: 51

PostPosted: Mon Jul 17, 2006 11:30 pm    Post subject: Re: Ranging and Pioneer Reply with quote

In message <1153038223.243208.252860@s13g2000cwa.googlegroups.com>,
"John (Liberty) Bell" <john.bell@accelerators.co.uk> writes
Quote:

Richard Saam wrote:
Oh No wrote:

The position of Pioneer was calculated from Doppler information. Ranging
was not available. Can anyone explain why ranging could not be used? Is
this just a limit on available technology, or is there a more
fundamental reason?


Regards


Here is an extreme case
in terms of Beta Pictoris
at many light years distance

arXiv:astro-ph/0601244 v1 11 Jan 2006

Dynamic motions are inferred from
atomic molecular quantum transitions.

The time (frequency) of such transitions are assumed the same
there and here
from which observed differences in frequencies
are related to dynamic motions.

The problem is the same as you identify.
How does one "range" the motions of Asteroid size objects
(which do not have quantum transitions) in Beta Pictoris
other than observing the gross newtonian gravity motions of the system
as a whole.

The problem could be solved if only a radar signal could be sent,
reflected for obtaining active ranging information.

In fact, with the (still functional) Pioneer, the possibility of
obtaining ranging data is enhanced by the fact that it contains a
narrow beam broadcast antenna directed towards the Earth, which can be
turned on and off via ground control.

Whether or not NASA thought to accuirately design and measure such turn
on/off delays prior to launch, in order to facilitate such a ranging
test, is, of course, another matter.

Even when Pioneer 10 and 11 were fully functional (and contact was lost
with 11 in 1995 and 10 in 2003) the fact remains that they couldn't do
the type of ranging involving transmitting and receiving a modulated
signal that was done with Galileo and Ulysses. They certainly wouldn't
have used anything as drastic as turning the transmitter on and off.
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Craig Markwardt
science forum addict


Joined: 16 Jun 2005
Posts: 66

PostPosted: Tue Jul 18, 2006 5:48 pm    Post subject: Re: Ranging and Pioneer Reply with quote

"John (Liberty) Bell" <john.bell@accelerators.co.uk> writes:
Quote:
Oh No wrote:
The position of Pioneer was calculated from Doppler information.

This statement is misleading. The position(s) of Pioneer(s) at any
given time was calculated using classical trajectory dynamics (with GR
corrections taken into account). So was the anticipated velocity hence
Doppler shift of antenna signal at any given time. What was observed by
NASA/JPL was an accumulating deviation from predicted Doppler shift,
which led Anderson et al. to infer an apparent classically anomalous
acceleration of the probes.

These apparent classically anomalous accelerations were tabulated
against predicted positions, not against altered positions inferred
from such apparent classically anomalous accelerations of the probes.

Your statement is also misleading. While it is true that the
trajectory was "predicted" by classical mechanics, what you don't say
is that the parameters of the trajectory (initial conditions) were
adjusted in order to provide the best possible fit of the model to the
Doppler observations. Thus in a very real sense, the Doppler
observations can be used to "calculate" the position of the Pioneer
spacecraft. Despite the adjustment of all possible classical "knobs"
in the model, the anomaly remains.

CM
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