Ranging and Pioneer

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.

Thus spake Oz
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/encyclo...r_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

Oh No writes
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.

"John (Liberty) Bell" writes:
Jonathan Silverlight wrote:
In message .com,
"John (Liberty) Bell" 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.

Your claim is incorrect. From Turyshev et al (gr-qc/0512121),

... The power source on Pioneer 10 finally degraded to the point
where the signal to Earth dropped below the threshold for detection
in its latest contact attempt on 7 February, 2003. The previous
three contacts had very faint signals with no telemetry
received. The last telemetry data point was obtained from Pioneer 10
on 27 April 2002 when the craft was 80 AU from the Sun.


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.


The spacecraft antenna was not "switched off." From Anderson et al.,

"The two spacecraft transmit continuously at a power of eight watts."
(sect. II. D.)

"The radiated power has been kept constant in time, independent of
the coverage from ground stations. That is, the radio transmitter is
always on, even when not received by a ground station."
(sect. VIII. A.)

Furthermore, it was never possible to do accurate ranging to the
Pioneer spacecraft (Anderson et al), so your claims are entirely
unsubstantiated.

CM

In message .com,
"John (Liberty) Bell" writes

Jonathan Silverlight wrote:

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,

Would you like to cite a source for that? Anyway, what do you mean "with
its antenna turned off"? The Pioneers used travelling wave tubes in
their transmitters, and although they were occasionally turned off
everyone was surprised when they were turned on again and still worked
:-)

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.

Quite apart from more formal publications, the Pioneer anomaly has been
discussed on Usenet for at least five years
http://groups.google.com/group/sci.p...hread/a88ae76f
f5a0f575/c3f9417441fff44e?lnk=st&q=%22pioneer+anomaly%22+tu ryshev&rnum=1#
c3f9417441fff44e
http://tinyurl.com/pdk47 and it's been established by correspondence
with Slava Turyshev that a simple round-trip time measurement isn't
sufficiently accurate to solve the problem, even if it could be done.
You _have_ done some research on this topic, haven't you?
--
Mail to jsilverlight at the address shown is more likely to be seen!

Craig Markwardt wrote:
"John (Liberty) Bell" writes:
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.

As is yours.

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.

And, presumably, to match with the known positions of planets at the
times they were used to catapault these probes into their final
trajectories.

Whilst Anderson et al. did not clarify how initial conditions were
established in the papers I read, they did confirm that such anomalous
accelerations have been known about since the 1980's. I saw no
evidence of later attempts to revise these initial conditions, to
provide a better match to subsequent Doppler observations.

If you know otherwise, I would appreciate references.

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

Uncle Al wrote:

http://arXiv.org/abs/gr-qc/0307042
Rationalized Pioneer anomaly
http://arXiv.org/abs/gr-qc/9810085
Believable rationalized Pioneer anomaly

I fail to see the logic of these explanations. Expansion of the
universe is signalled by increasing redshift at greater distances. If
the Pioneers are 'swept along' by this universal expansion, then they
too should exhibit an increasing classically unmodelled redshift. If
they are not, then no resultant Doppler shift should be experienced.
However, what was observed was an increasing classically unmodelled
blue shift.

It seems to me that these authors have assumed a coordinate system
where the universal expansion is transparent, assumed that the Pioneer
trajectories do not participate in that universal expansion, concluded
therefrom that they will thus appear to experience a classically
unmodelled deceleration, and have then conveniently forgotten that said
universal expansion gives a redshift, thus concluding that failure to
participate in said expansion will result in the observed increasing
blueshift.

If I have missed something important here, I would like an explanation
of what it is.

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

Oh No wrote:


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/encyclo...r_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.

Presumably it should be considerably cheaper than other missions since
only a transmitter needs to be boosted to high speeds?

Dirk

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.

John (Liberty) Bell writes
I fail to see the logic of these explanations. Expansion of the
universe is signalled by increasing redshift at greater distances. If
the Pioneers are 'swept along' by this universal expansion, then they
too should exhibit an increasing classically unmodelled redshift. If
they are not, then no resultant Doppler shift should be experienced.
However, what was observed was an increasing classically unmodelled
blue shift.

Charles Francis' proposal (gr-qc/0604047 backed by gr-qc/0604047, gr-
qc/0605127) places the shift as a correction due to quantum gravity
since photons are essentially quantised. The same effect modified by
being seen "edgeways on" produces a shift that matches the doppler shift
that mond seeks to explain but with this explanation the galaxies rotate
in a newtonian manner when the doppler shift is properly interpreted.

--
Oz
This post is worth absolutely nothing and is probably fallacious.