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Ranging and Pioneer
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Oz
science forum Guru Wannabe


Joined: 30 Apr 2005
Posts: 155

PostPosted: Thu Jul 20, 2006 8:59 am    Post subject: Re: Ranging and Pioneer Reply with quote

Oh No <NotI@charlesfrancis.wanadoo.co.uk> writes
Quote:
One might have thought the New Horizons mission an ideal opportunity, as
the craft was powered straight into an escape trajectory

Arrives pluto 2015.

Jupiter slingshot to 32 jovian radii.

Presumably a slingshot that went to say 3 jovian radii would result in a
very significant exit velocity compared to the 11km/s achieved here.

--
Oz
This post is worth absolutely nothing and is probably fallacious.
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Oh No
science forum addict


Joined: 06 Apr 2006
Posts: 82

PostPosted: Wed Jul 19, 2006 2:43 pm    Post subject: Re: Ranging and Pioneer Reply with quote

Thus spake Oz <Oz@farmeroz.port995.com>
Quote:
It seems to me that a repeat test simply requires a modest satellite to
exit the solar system as rapidly as possible.

Since the direction and basic design would appear to be uncritical the
key issue appears to be speed.

I imagine a modern design would be rather small and light and comprise
little more than a small box of electronics, a radioactive power source
and a large dish.

Given the direction is uncritical presumably a multiple slingshot path
could be devised so as to achieve maximum speed despite using a modest
launcher. It is (for example) plausible to do multiple slingshots
skimming (say) mercury, the moon and jupiter?

It would be quite helpful if we didn't have to wait 30 years for a
result....

One might have thought the New Horizons mission an ideal opportunity, as
the craft was powered straight into an escape trajectory

http://ccar.colorado.edu/~nerem/zipfiles/hunkins/

Launched in January, New Horizons has already crossed the orbit of Mars
and is now crossing the asteroid belt. It will reach Jupiter next
February. It's the fastest spacecraft ever flown.

Alas, the spacecraft will very likely be unsuitable for Pioneer Effect
experiments for another reason: "Unfortunately, New Horizons suffers
from a similar drawback in this respect to the Cassini spacecraft -
namely, that its RTGs are mounted close to the spacecraft's body, so
infrared radiation from them, bouncing off the spacecraft, will produce
a systematic thrust of a not-easily predicted magnitude, several times
as large as the Pioneer effect."

From:
http://www.daviddarling.info/encyclopedia/P/Pioneer_anomaly.html

I don't know, but this may be a problem with all recently built fission-
powered space vehicles.

Nieto et al have been campaigning for a special mission, but I don't
know if they have even got as far as formally applying for funding.


Regards

--
Charles Francis
substitute charles for NotI to email
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Oz
science forum Guru Wannabe


Joined: 30 Apr 2005
Posts: 155

PostPosted: Wed Jul 19, 2006 7:29 am    Post subject: Re: Ranging and Pioneer Reply with quote

It seems to me that a repeat test simply requires a modest satellite to
exit the solar system as rapidly as possible.

Since the direction and basic design would appear to be uncritical the
key issue appears to be speed.

I imagine a modern design would be rather small and light and comprise
little more than a small box of electronics, a radioactive power source
and a large dish.

Given the direction is uncritical presumably a multiple slingshot path
could be devised so as to achieve maximum speed despite using a modest
launcher. It is (for example) plausible to do multiple slingshots
skimming (say) mercury, the moon and jupiter?

It would be quite helpful if we didn't have to wait 30 years for a
result....

--
Oz
This post is worth absolutely nothing and is probably fallacious.
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John Bell
science forum addict


Joined: 31 Dec 2005
Posts: 84

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

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

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.

Notwithstanding the fact that Anderson et al. claimed (I think in 2004)
that Pioneer 10 was still functional, with its antenna turned off to
conserve energy, the fact remains that, if their reported apparent
anamolous acceleration is real, this should mean that the effect of
turning the antenna on or off should, by now, be observable on Earth
more than 1 second before originally expected.

Knowledge of the antenna turn on/off times to an accuracy better than
this, is, I suggest, not too much to ask for the adequate pre-launch
documentation of a piece of kit (and space program) of this cost.

Performing such a proposed test is hardly drastic, and far from
expensive (if adequate pre-launch documentation exists), given that
NASA/JPL have already turned off the antenna, and plan on switching it
on again at some unspecified time in the future.

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


Joined: 31 Dec 2005
Posts: 84

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

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

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)

According to Anderson et al. contact was not lost with Pioneer 10. The
transmitter was switched off via ground control to conserve energy,
thereby allowing it to be switched on again at a later date, for
further tests.

Quote:
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.

No, but they could now, if they knew switch on/off times accurately, in
order to test whether the unexpected apparent anomalous acceleration
had real consequences in terms of resultant reduced elapsed distance.

John (Liberty) Bell
http://global.accelerators.co.uk
(Change John to Liberty to respond by email)
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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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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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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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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

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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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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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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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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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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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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