Pioneer Anomaly Anomalous No More.

Max Keon wrote:

"George Dishman" wrote in message
ups.com...

Max, I doubt there is much more we can discuss. You
just keep repeating statements that are grossly wrong
and I can't help you see why until you learn what vectors
are and how to manipulate them. I'll respond this time but
I doubt I'll continue much longer. Your theory does not
predict any of the things you are claiming especially the
Pioneer anomaly and galactic rotation curves. You need
to revise your basic maths and mechanics before trying
to work on this.

The maths you are using is based on logic which is not applicable
in the zero origin universe.

The maths I am using is _your _equation.

A gravity anisotropy doesn't exist
according to you, so how could it possibly not cause conflicts
when it's introduced into your maths.

Maths is a tool independent of the physics. Your
equation is supposed to tell me what effect your
anisotropy has and I have just applied that.

The maths must be designed
to incorporate such a thing.

And I assume that is what your equation does.

None of what I propose is wrong in nature. It depends entirely on
how the evidence is interpreted.

The interpretation is supposed to be stated by your
equation. The equation only produces one result
which is what I have worked out for you.

According to the info provided by John Pazmino in a reply to this
thread, posted only to sci.astro, the Pioneer anomaly is the topic
of the 2007 Isaac Asimov Debate. It takes place on 26-3-07 in the
American Museum of Natural History. "A team of expert from
astrodynamics and astronautics will sit in panel in the Museum's
LeFrak theater to argue out what the hell IS this misbehavior of
the Pioneer spacecraft."

Let's hope something positive comes out of it, like the launching
of a proper mission to test the Pioneer anomaly.

That would be nice but unlikely. You don't seem to
understand the difficulty of getting funding.

It cannot
possibly be resolved any other way. Judging by Anderson's paper
http://arxiv.org/gr-qc/0104064 , conclusive proof either way is
not a possibility. That will obviously not change regardless of
what happens at the conference, unless a proper test eventuates.

We've had nearly 30 years to do it, so why hasn't it been done?
Would you like me to tell you what I think?

You've done nothing else for weeks and it is based on
a fantasy world weher unlimited money is available for
launching spacecrfat without having any idea what
instruments to put on board to resolve a question in
the hope of blundering across an answer. Anderson
and Turyshev have already made a number of proposals
for new missions but they haven't yet succeeded in
making the case that sufficient scientific return would
be obtained.

It's apparent that neither of us will concede one inch of ground
regarding the Pioneer anomaly, so I'll snip most of my reply.

There is no ground to be given, the anomalous motion
of the craft is measured and you have to explain that,
not invent some non-existent tangential effect just
because you don't like the fact that energy and
momentum are being lost.

One thing that really needs to be addressed though is the
instantaneous action at a distance that was proposed by Newton
to explain why the planets don't spiral into the Sun. That is
completely wrong of course.

Yes, but GR already does that very elegantly in the
form of the metric.

GR may well have tied itself up in knots trying to explain the
reverse of what would actually happen. So the fortress may begin
to tumble down after all.

The binary star pair diagram that I previously posted
demonstrates beyond any doubt that the two stars would spiral
away from each other.

+ 0-


. (center of mass)


-0 +

Each "0" is offset to the "+" and that's where each star appears
to be according to the other. Each "+" is the focal point of
their respective orbits.


No Max, you are off into fantasy world again. The
focal point of elliptical orbits is the barycentre. The
slight effect of a delay would move them from there
so you get a diagram like this:

0-


+ . +


-0



Now we have the problem of explaining why the planets don't
eternally spiral outwards. It shouldn't be too hard to understand
that, without invoking the ridiculous.

It isn't GR does it very nicely.

Truth has now raised its ugly head, and it will never go away.

The truth is that, before Christmas, you couldn't even simplify
your own equation or understand signed velocities which is
a level of algebra that you should have matered by the age
of 12. Hopefully that problem has gone away if you studied
the web page I gave you.

Right now, the fact is that you cannot handle vectors and
don't seem to know what they are. Since the acceleration in
your equation is a vector and so is the momentum that it
changes, you are incapable of working out what your
equation (theory) tells you about orbits or anything else.

You may have set out to demolish the zero origin concept, ..

Nope. I set out to explore its consequences to see whether
there was any existing evidence either for or against. The
result was that, if it explained the Pioneer anomaly, then it
also requires the planets to spiral into the Sun, Mercury
in about 1 million years. Your theory isn't dead but the
"mass of the rest of the universe" value you use must be
small enough to avoid the demise of the planets, and that
means the effect cannot be more than a tiny fraction of
the Pioneer anomaly, well below the noise.

The best way to test your theory remains with the change
it would cause in the _eccentricity_ of Mercury's orbit
which we haven't analysed fully.

George

"George Dishman" wrote in message
oups.com...
Max Keon wrote:
"George Dishman" wrote in message
ups.com...

Max, I doubt there is much more we can discuss. You
just keep repeating statements that are grossly wrong
and I can't help you see why until you learn what vectors
are and how to manipulate them. I'll respond this time but
I doubt I'll continue much longer. Your theory does not
predict any of the things you are claiming especially the
Pioneer anomaly and galactic rotation curves. You need
to revise your basic maths and mechanics before trying
to work on this.

The maths you are using is based on logic which is not applicable
in the zero origin universe.

The maths I am using is _your _equation.

But you are using my equation in the wrong universe.

A gravity anisotropy doesn't exist
according to you, so how could it possibly not cause conflicts
when it's introduced into your maths.

Maths is a tool independent of the physics. Your
equation is supposed to tell me what effect your
anisotropy has and I have just applied that.

Don't be ridiculous. Did the maths invent the big bang universe,
or did that universe determine how the maths would be applied?
If theory predicts a CMBR, the maths is applied accordingly. If
a gravity anisotropy is predicted, the maths is applied
accordingly. But when maths starts predicting things to fill
holes in a theory, that is cause for alarm, _don't you think_?
Such a thing would leave us completely in the dark.

The maths must be designed
to incorporate such a thing.

And I assume that is what your equation does.

It certainly does in the zero origin universe.

None of what I propose is wrong in nature. It depends entirely on
how the evidence is interpreted.

The interpretation is supposed to be stated by your
equation. The equation only produces one result
which is what I have worked out for you.

You are still in the wrong universe. My equation doesn't design
the zero origin universe, the universe designs the equation.

According to the info provided by John Pazmino in a reply to this
thread, posted only to sci.astro, the Pioneer anomaly is the topic
of the 2007 Isaac Asimov Debate. It takes place on 26-3-07 in the
American Museum of Natural History. "A team of expert from
astrodynamics and astronautics will sit in panel in the Museum's
LeFrak theater to argue out what the hell IS this misbehavior of
the Pioneer spacecraft."

Let's hope something positive comes out of it, like the launching
of a proper mission to test the Pioneer anomaly.

That would be nice but unlikely. You don't seem to
understand the difficulty of getting funding.

It cannot
possibly be resolved any other way. Judging by Anderson's paper
http://arxiv.org/gr-qc/0104064 , conclusive proof either way is
not a possibility. That will obviously not change regardless of
what happens at the conference, unless a proper test eventuates.

We've had nearly 30 years to do it, so why hasn't it been done?
Would you like me to tell you what I think?

You've done nothing else for weeks and it is based on
a fantasy world weher unlimited money is available for
launching spacecrfat without having any idea what
instruments to put on board to resolve a question in
the hope of blundering across an answer.

How hard would it be to send exactly the same Pioneer 10-11
configuration on a trip to Neptune and back? How hard would it be
to detect the anomalous acceleration on the outward and inward
legs? How hard would it be to notice that one is pointing in the
opposite direction to the other, relative to the Sun? Whatever is
the cause, there should be some sort of anisotropy evident in the
result.

It would be best if the new Pioneer's trajectory path for both
legs was as close as possible to a direct line between the Sun
and Neptune. And measurements only need to be taken between the
Uranus orbit radius and Neptune, where the anomaly is clearly
evident.

There must surely be something else we need to know about Neptune
while Pioneer is out there?

Anderson
and Turyshev have already made a number of proposals
for new missions but they haven't yet succeeded in
making the case that sufficient scientific return would
be obtained.

The scientific return is that theoretical physics has been put
to the test and has emerged victorious. Or it has failed. The
anomaly will remain a thorn in the side of physics while it's
left unresolved. All progress of any consequence will in fact
cease.

One thing that really needs to be addressed though is the
instantaneous action at a distance that was proposed by Newton
to explain why the planets don't spiral into the Sun. That is
completely wrong of course.

Yes, but GR already does that very elegantly in the
form of the metric.

But GR's amazing feat is quite irrelevant anyway because
instantaneous action at a distance was never a requirement in
anybody's gravity. The planets would naturally spiral outwards,
not inwards, and would always fall into a natural orbit
somewhere.

GR may well have tied itself up in knots trying to explain the
reverse of what would actually happen. So the fortress may begin
to tumble down after all.

The binary star pair diagram that I previously posted
demonstrates beyond any doubt that the two stars would spiral
away from each other.

+ 0-


. (center of mass)


-0 +

Each "0" is offset to the "+" and that's where each star appears
to be according to the other. Each "+" is the focal point of
their respective orbits.

No Max, you are off into fantasy world again. The
focal point of elliptical orbits is the barycentre. The
slight effect of a delay would move them from there
so you get a diagram like this:

+ 0-


+ . +


-0 +

I've fixed the diagram for you. The apparent position of each
star is along a direct line through each barycenter.

Now we have the problem of explaining why the planets don't
eternally spiral outwards. It shouldn't be too hard to understand
that, without invoking the ridiculous.

It isn't GR does it very nicely.

As does everyone else's theory.

Truth has now raised its ugly head, and it will never go away.

The truth is that, before Christmas, you couldn't even simplify
your own equation or understand signed velocities which is
a level of algebra that you should have matered by the age
of 12. Hopefully that problem has gone away if you studied
the web page I gave you.

Perhaps you should try living in my world for a while.

Anyway; This is how I described the cause of the anisotropy at
http://www.optusnet.com.au/~maxkeon/pionomor.html

---------
The story unfolds as a direct consequence of a universe which
came into being from absolutely nothing, a zero origin universe
in fact. In that universe, light doesn't actually propagate
anywhere, but it does move relative to a base that is set by the
combined input from all local matter, anywhere, i.e. the Earth.
According to the laws of that universe, the entire dimension
surrounding every bit of matter in the universe is shifting
inward into its own gravity well at the rate of (G*M/r^2)*2
meters in each second and is updated at the speed of light.
Meaning that its acceleration capability diminishes to zero for
anything moving at light speed toward its center of mass. The
shift rate of dimension is necessarily twice the shift rate of
the matter that the moving dimension carries along with it,
otherwise there would be no driving mechanism available to
perform the task.

The equation representing an upward moving mass relative to a
gravity source is ((c+v)^2/c^2)^.5*G*M/r^2-(G*M/r^2), while
((c-v)^2/c^2)^.5*G*M/r^2-(G*M/r^2) represents a downward moving
mass. Even matter in a fixed position relative to a gravity
source is traveling outward through dimension because dimension
is traveling inward through it, hence the action of gravity.

According to the conventional method of identifying gravity
force direction, and the conventional method of identifying
velocity direction relative to a gravity source, just the one
equation is all that's required. But what it attempts to describe
is not as clear. ((c+v)^2/c^2)^.5*(-G*M/r^2)+(G*M/r^2)
---------

That entire description is very easy to follow, for anybody,
right down to the final correction. I choose to not simplify it
because that would diminish its purpose. Why should I turn it
into this, v/c(-GM/r^2) ? That is certainly how it should be
used, but does it in any way represent the message I'm trying to
convey? It will stay as it is for now.

You may have set out to demolish the zero origin concept, ..

Nope. I set out to explore its consequences to see whether
there was any existing evidence either for or against. The
result was that, if it explained the Pioneer anomaly, then it
also requires the planets to spiral into the Sun, Mercury
in about 1 million years.

That wasn't the case at all. I'll try to explain each step of the
process in some detail (for my own benefit).

The conclusion was that no energy (or momentum) can be
immediately absorbed by the matter of the universe, so the force
remains like a spring which is applying a constant restraining
force on Mercury's orbital motion. That action will of course
initially slow Mercury, which in turn will begin a slow
acceleration toward the Sun. As you say, that reaction cannot be
elastic, and momentum is lost. But still no energy has been
transferred away from what can only be a locally closed system.
The momentum loss immediately converts to potential energy, which
in turn slowly converts to kinetic energy.

According to your maths, that process continues until Mercury
hits the Sun in a million years or so. But that's not the case at
all because centrifugal forces increase at a squaring rate per
velocity increase, while the orbit velocity is slowed at a linear
rate. When Mercury has fallen so far that it's orbit velocity per
orbit radius is such that the freefall rate to the Sun is
3.2e-9m/sec^2 greater than it would normally be for the orbit
radius (orbiting faster than expected according to your maths),
the added centrifugal force will counteract the elastic force
applied by the universe. Mercury will be thrown outwards as fast
as it falls inwards.

http://www.optusnet.com.au/~maxkeon/merc-un.gif

That's exactly why the planets arrive at a stable orbit
regardless of where the barycenter may be wandering, in a
_closed system_.

The best way to test your theory remains with the change
it would cause in the _eccentricity_ of Mercury's orbit
which we haven't analysed fully.

The eccentricity would not be affected by the universe generated
gravity anisotropy at all when Mercury arrives at a stable orbit.

The need for instantaneous action at a distance to overcome the
problem of the planets spiraling into the Sun should have
sounded alarm bells. It's a little disconcerting to think that
Newton chose the impossible over the obvious, that he really
didn't understand gravity at all. GR just sidesteps the issue.

-----

Max Keon

"Max Keon" wrote in message
...

"George Dishman" wrote in message
oups.com...
Max Keon wrote:
"George Dishman" wrote in message
ups.com...

Max, I doubt there is much more we can discuss. You
just keep repeating statements that are grossly wrong
and I can't help you see why until you learn what vectors
are and how to manipulate them. I'll respond this time but
I doubt I'll continue much longer. Your theory does not
predict any of the things you are claiming especially the
Pioneer anomaly and galactic rotation curves. You need
to revise your basic maths and mechanics before trying
to work on this.

The maths you are using is based on logic which is not applicable
in the zero origin universe.

The maths I am using is _your _equation.

But you are using my equation in the wrong universe.
....
Maths is a tool independent of the physics. Your
equation is supposed to tell me what effect your
anisotropy has and I have just applied that.

Don't be ridiculous. Did the maths invent the big bang universe,
or did that universe determine how the maths would be applied?
If theory predicts a CMBR, the maths is applied accordingly. If
a gravity anisotropy is predicted, the maths is applied
accordingly. ...

The maths must be designed
to incorporate such a thing.

And I assume that is what your equation does.

It certainly does in the zero origin universe.

Then when I use your equation, it will tell me what will
happen in the zero origin universe. That's what I do and
the result is a consequence you didn't anticipate and don't
like, but that's what it is.

You are still in the wrong universe. My equation doesn't design
the zero origin universe, the universe designs the equation.

Sure, and then the equation tells us what will happen to
the planets in your universe - they spiral into the Sun.
Theories often have consequences that weren't anticipated
by their originators. Planck could never have known the
consequences of his original lecture on quantisation as a
solution to black body radiation.

You've done nothing else for weeks and it is based on
a fantasy world weher unlimited money is available for
launching spacecrfat without having any idea what
instruments to put on board to resolve a question in
the hope of blundering across an answer.

How hard would it be to send exactly the same Pioneer 10-11
configuration on a trip to Neptune and back?

Several million dollars hard.

How hard would it be
to detect the anomalous acceleration on the outward and inward
legs? How hard would it be to notice that one is pointing in the
opposite direction to the other, relative to the Sun? Whatever is
the cause, there should be some sort of anisotropy evident in the
result

Sure, but that gets you no farther forward in identifying
the _cause_ of the effect. What instrumentation are you
proposing to fly to determine that?

There must surely be something else we need to know about Neptune
while Pioneer is out there?

Maybe, but that would mean changing a Neptune mission
to remove attitude control by thrusters and redesigning
an existing mission - who is going to pay for that? Why
would the mission agree to remove instruments designed
to study Neptune and replace them with instruments to
study the anomaly? Who would refund the cost of the
unused Neptune instruments? As I say, you seem to live
in a fantasy world of unlimited funds.

Anderson
and Turyshev have already made a number of proposals
for new missions but they haven't yet succeeded in
making the case that sufficient scientific return would
be obtained.

The scientific return is that theoretical physics has been put
to the test and has emerged victorious. Or it has failed.

Then you need to tell everyone what instruments you are
going to fly and how it will resolve one theory over
another. First though you need to have a competing theory
to test that doesn't send the planets into the Sun as your
equation does at present.

One thing that really needs to be addressed though is the
instantaneous action at a distance that was proposed by Newton
to explain why the planets don't spiral into the Sun. That is
completely wrong of course.

Yes, but GR already does that very elegantly in the
form of the metric.

But GR's amazing feat is quite irrelevant anyway because
instantaneous action at a distance was never a requirement in
anybody's gravity.

It was in Newton's.

The planets would naturally spiral outwards,
not inwards, and would always fall into a natural orbit
somewhere.

Nope, they spiral forever. You really need to go back
and learn vectors if you want to join in science groups.

GR may well have tied itself up in knots trying to explain the
reverse of what would actually happen. So the fortress may begin
to tumble down after all.

The binary star pair diagram that I previously posted
demonstrates beyond any doubt that the two stars would spiral
away from each other.

+ 0-


. (center of mass)


-0 +

Each "0" is offset to the "+" and that's where each star appears
to be according to the other. Each "+" is the focal point of
their respective orbits.

No Max, you are off into fantasy world again. The
focal point of elliptical orbits is the barycentre. The
slight effect of a delay would move them from there
so you get a diagram like this:

0-


+ . +


-0

I've fixed the diagram for you.

No, you have screwed it up again so I restored what
I wrote. Go and learn vectors, then read up on the
two-body problem

The apparent position of each
star is along a direct line through each barycenter.

The distance from the star to the focal point of
its orbit is much less than that to the other star.

Now we have the problem of explaining why the planets don't
eternally spiral outwards. It shouldn't be too hard to understand
that, without invoking the ridiculous.

It isn't GR does it very nicely.

As does everyone else's theory.

Except yours.

Truth has now raised its ugly head, and it will never go away.

The truth is that, before Christmas, you couldn't even simplify
your own equation or understand signed velocities which is
a level of algebra that you should have matered by the age
of 12. Hopefully that problem has gone away if you studied
the web page I gave you.

Perhaps you should try living in my world for a while.

No thanks, I like the Earth where it is.

The equation representing an upward moving mass relative to a
gravity source is ((c+v)^2/c^2)^.5*G*M/r^2-(G*M/r^2), while
((c-v)^2/c^2)^.5*G*M/r^2-(G*M/r^2) represents a downward moving
mass.

In which case the anisotropic force pushes the body
in the same direction regardless of the direction of
motion, the opposite of what you told me.

Even matter in a fixed position relative to a gravity
source is traveling outward through dimension because dimension
is traveling inward through it, hence the action of gravity.

Yes, gravity is always towards the other body but
the anisotropic part changes direction depending on
the velocity. Your two equations say the anisotropic
part is always in the _same_ direction.

According to the conventional method of identifying gravity
force direction, and the conventional method of identifying
velocity direction relative to a gravity source, just the one
equation is all that's required. But what it attempts to describe
is not as clear. ((c+v)^2/c^2)^.5*(-G*M/r^2)+(G*M/r^2)
---------

That entire description is very easy to follow, for anybody,
right down to the final correction. I choose to not simplify it
because that would diminish its purpose. Why should I turn it
into this, v/c(-GM/r^2) ? That is certainly how it should be
used, but does it in any way represent the message I'm trying to
convey?

For anyone who understands maths, it conveys it more
clearly than your version, but as long as you keep the
same equation you at least get the direction of the
anisotropy correct.

It will stay as it is for now.

You may have set out to demolish the zero origin concept, ..

Nope. I set out to explore its consequences to see whether
there was any existing evidence either for or against. The
result was that, if it explained the Pioneer anomaly, then it
also requires the planets to spiral into the Sun, Mercury
in about 1 million years.

That wasn't the case at all. I'll try to explain each step of the
process in some detail (for my own benefit).

The conclusion was that no energy (or momentum) can be
immediately absorbed by the matter of the universe,

That's fine, but energy is being removed by the anisotropy
immediately, it is up to you to say where it goes.

so the force
remains like a spring ..

No it isn't. A spring always pulls in the same direction
like gravity but your anisotropy changes direction. A
spring removes and stores energy while being stretched
and returns it while being relaxed because the force is
in the same direction as the speed. Your anisotropy
absorbs energy (and could store it though you haven't
said) while the bodies move apart, but when they move
towards each other, the force changes direction so still
opposes the velocity and continues to remove more energy.

There is no direction of motion in which energy is returned
to the body so the anisotropic force is not elastic.

which is applying a constant restraining
force on Mercury's orbital motion. That action will of course
initially slow Mercury, which in turn will begin a slow
acceleration toward the Sun. As you say, that reaction cannot be
elastic, and momentum is lost.

As is energy.

But still no energy has been
transferred away from what can only be a locally closed system.

You could hypothesise that the energy and momentum
are stored somewhere locally but that is for you to
work out.

The momentum loss immediately converts to potential energy, which
in turn slowly converts to kinetic energy.

Wrong, momentum and energy are not interchangeable, they
are separate quantities, both of which must be separately
conserved (as must the three spatial components of momentum).

According to your maths, that process continues until Mercury
hits the Sun in a million years or so.

No, according to _your_ equation, that's what happens.
I just applied it for you without making your mistake
of confusing energy and momentum.

The eccentricity would not be affected by the universe generated
gravity anisotropy at all when Mercury arrives at a stable orbit.

You won't be able to work out what it does until you
learn how to handle vectors, differential equations and
the difference between energy and momentum.

The need for instantaneous action at a distance to overcome the
problem of the planets spiraling into the Sun should have
sounded alarm bells.

It did and people were trying to resolve it for 200
years until Einstein found the solution.

It's a little disconcerting to think that
Newton chose the impossible over the obvious, ..

What you think is "obvious" doesn't work, and Newton
knew that, he invented the physics that you should
have learned at school which would stop you making
these errors.

George

George Dishman replied to Max Keon:

How hard would it be to send exactly the same Pioneer 10-11
configuration on a trip to Neptune and back?

Several million dollars hard.

The cost of building the spacecraft and the launch
vehicles, launching them, and communicating with them
for about 20 years-- Upwards of 2 billion dollars.
The cost savings of not having to design an entirely
new spacecraft from scratch would probably be balanced
by having to design the new spacecraft to retain the
desired properties of the Pioneers.

From http://saturn.jpl.nasa.gov/faq/mission.cfm
--------
The total cost of the Cassini-Huygens mission is about
$3.26 billion, including $1.4 billion for pre-launch
development, $704 million for mission operations,
$54 million for tracking and $422 million for the
launch vehicle. The U.S. contributed $ 2.6 billion,
the European Space Agency $500 million and the Italian
Space Agency $160 million.
--------

The Pioneers were funded by US federal taxes. Since
this new project is above and beyond anything that NASA
has funding for or could get funding for, it would have
to be funded privately. Since I suspect that the Deep
Space Network is already stretched to the limit, at
least one new 70-meter-class communications dish would
need to be built. That might actually be an incentive
to do the project. Each dish would probably cost from
50 to 100 million dollars to build, and could be for
other missions during the same time period that they
would be supporting the new project, and after.

-- Jeff, in Minneapolis

"Jeff Root" writes:
George Dishman replied to Max Keon:

How hard would it be to send exactly the same Pioneer 10-11
configuration on a trip to Neptune and back?

Several million dollars hard.

The cost of building the spacecraft and the launch
vehicles, launching them, and communicating with them
for about 20 years-- Upwards of 2 billion dollars.
The cost savings of not having to design an entirely
new spacecraft from scratch would probably be balanced
by having to design the new spacecraft to retain the
desired properties of the Pioneers.

From http://saturn.jpl.nasa.gov/faq/mission.cfm
--------
The total cost of the Cassini-Huygens mission is about
$3.26 billion, ...

A better mission to compare to would probably be New Horizons, the
"express" mission to Pluto. The comparison is good because one would
probably want a Pioneer-like mission to the outer solar system where
the cruise phase was shorter than the average person's career.
Wikipedia quotes a cost of $650M for New Horizons.

The Pioneers were funded by US federal taxes. Since
this new project is above and beyond anything that NASA
has funding for or could get funding for, it would have
to be funded privately. ...

NASA does have opportunities for new missions which are heavily
competed for, but those opportunities have ... er... decreased
significantly in frequency in the past few years.

One problem with a "new gravity" mission is that one would want a very
simple mission with few instruments and physical structures, in order
to avoid systematics like solar radiation pressure effects. On the
other hand, even simple deep space missions are very expensive (launch
services alone would be at least $150M, plus a deep space mission
can't rely on solar power), so NASA would want a lot of "bang for the
buck." It would be a delicate balancing act to get a simple "new
gravity" mission more highly ranked than other mission proposals with
well-stocked science portfolios.


... Since I suspect that the Deep
Space Network is already stretched to the limit, at
least one new 70-meter-class communications dish would
need to be built. That might actually be an incentive
to do the project. Each dish would probably cost from
50 to 100 million dollars to build, and could be for
other missions during the same time period that they
would be supporting the new project, and after.

I suspect that by the time a new mission would be ready for launch,
the subscription rate to DSN may be lower, but that really depends on
the actual spacecraft traffic to Mars.

Craig

Craig,

I made a mistake in thinking that Max was specifying
two spacecraft, because he said "Pioneer 10-11". I now
think he only meant one, which would cut the cost a lot,
not least because of the reduction in DSN time. It might
even cut the total cost in half. Not that my estimate was
much better than order-of-magnitude to begin with.

On the other hand, I wonder if you noticed that Max
specified "to Neptune and *back*"?

I don't know how much cost getting back would add, but
it would have to be a lot. I assumed that getting back
means a flyby within a few million km of Earth. I'm sure
that getting back means a slower trip out, thus my
estimate of "about 20 years" for the mission.

-- Jeff, in Minneapolis

"Jeff Root" writes:

Craig,

I made a mistake in thinking that Max was specifying
two spacecraft, because he said "Pioneer 10-11". I now
think he only meant one, which would cut the cost a lot,
not least because of the reduction in DSN time. It might
even cut the total cost in half. Not that my estimate was
much better than order-of-magnitude to begin with.

Hi Jeff,

The example you gave put the Cassini DSN time at $44M right, so it
ends up being significant, but still not the dominant component.


On the other hand, I wonder if you noticed that Max
specified "to Neptune and *back*"?

I don't know how much cost getting back would add, but
it would have to be a lot. I assumed that getting back
means a flyby within a few million km of Earth. I'm sure
that getting back means a slower trip out, thus my
estimate of "about 20 years" for the mission.


OK, I didn't notice that, and it makes the job much, much harder. I'm
not even sure it could be done. An orbit with perihelion at earth and
aphelion at Neptune has a period of about 60 years. I'm not sure if
gravity assist could be used, and of course the re-capture near earth
would be a major task.

Craig

--
--------------------------------------------------------------------------
Craig B. Markwardt, Ph.D. EMAIL:
Astrophysics, IDL, Finance, Derivatives | Remove "net" for better response
--------------------------------------------------------------------------

"Craig Markwardt" wrote in message
...
"Jeff Root" writes:
On the other hand, I wonder if you noticed that Max
specified "to Neptune and *back*"?

....

OK, I didn't notice that, and it makes the job much, much harder. I'm
not even sure it could be done. An orbit with perihelion at earth and
aphelion at Neptune has a period of about 60 years. I'm not sure if
gravity assist could be used, and of course the re-capture near earth
would be a major task.

Max's idea is to confirm that the anomaly changes direction
on an inward trip so to minimise systematics the plan would
be to launch on a fast, near radial trajectory out to say
Neptune, and then use a slingshot to bring the craft back
towards the Sun.

Re-capture would be unnecessary, all that's needed is a long
enough baseline to determine the anomaly on each leg. The
essential feature would be to have both Doppler and ranging
so that the two could be compared to eliminate or confirm
non-dynamic effects, i.e. things affecting the signal rather
than the craft.

That isn't too hard to envisage if all that is being flown is
a spin-stabilised transponder. The simplest craft might be
nothing more than a large corner reflector with just enough
thrusters to do a course correction and some autonomous
navigation facility, you wouldn't even need to communicate
with it.

My own thoughts on a mission have been on the lines of flying
a craft capable of receiving millisecond pulsar signals from
a number of sources simultaneously (using a synthetic aperture
technique) and using them like GPS to work out the location
and highly accurate timing on-board. Add an ensemble of atomic
clocks and you can measure and map the solar gravitational
potential by comparing the clocks to the pulsars to determine
the gravitational frequency shift. The self-determined location
could be radioed back and compared with the range and integrated
Doppler. It's a bit more expensive than the simpler reflector
but mapping the potential well of the Solar System might have a
chance of being seen as a new observation that could attract
some funds.

The problem I see with that is getting the timing resolution
from the pulsars. Pulse durations are quite large even for the
fastest repetition rates but on the other hand you get continuous
reception 24h a day. A 'millisecond' pulsar gives on the order of
10^6 pulses per hour so I guess maybe three orders of magnitude
improvement in timing, or roughly microsecond accuracy. It needs
tens of nanoseconds accuracy to be comparable to ranging data
which achieves tens of metres.

George

"George Dishman" writes:

"Craig Markwardt" wrote in message
...
"Jeff Root" writes:
On the other hand, I wonder if you noticed that Max
specified "to Neptune and *back*"?

...

OK, I didn't notice that, and it makes the job much, much harder. I'm
not even sure it could be done. An orbit with perihelion at earth and
aphelion at Neptune has a period of about 60 years. I'm not sure if
gravity assist could be used, and of course the re-capture near earth
would be a major task.

Max's idea is to confirm that the anomaly changes direction
on an inward trip so to minimise systematics the plan would
be to launch on a fast, near radial trajectory out to say
Neptune, and then use a slingshot to bring the craft back
towards the Sun.

That would be quite a difficult bit of maneuvering!

Re-capture would be unnecessary, all that's needed is a long
enough baseline to determine the anomaly on each leg. The
essential feature would be to have both Doppler and ranging
so that the two could be compared to eliminate or confirm
non-dynamic effects, i.e. things affecting the signal rather
than the craft.

That isn't too hard to envisage if all that is being flown is
a spin-stabilised transponder. The simplest craft might be
nothing more than a large corner reflector with just enough
thrusters to do a course correction and some autonomous
navigation facility, you wouldn't even need to communicate
with it.

Well begging to differ, but I think that having thrusters is probably
anathema to a sensitive anomaly measurement, especially autonomous
thrusters :-)

My previous point was that NASA gets a lot of competitive proposals
for missions, and it will be hard to get a "bare-bones" mission ranked
more highly than other missions, given the high fixed costs of each
planetary mission.


My own thoughts on a mission have been on the lines of flying
a craft capable of receiving millisecond pulsar signals from
a number of sources simultaneously (using a synthetic aperture
technique) and using them like GPS to work out the location
and highly accurate timing on-board. Add an ensemble of atomic
clocks and you can measure and map the solar gravitational
potential by comparing the clocks to the pulsars to determine
the gravitational frequency shift. The self-determined location
could be radioed back and compared with the range and integrated
Doppler. It's a bit more expensive than the simpler reflector
but mapping the potential well of the Solar System might have a
chance of being seen as a new observation that could attract
some funds.

The problem I see with that is getting the timing resolution
from the pulsars. Pulse durations are quite large even for the
fastest repetition rates but on the other hand you get continuous
reception 24h a day. A 'millisecond' pulsar gives on the order of
10^6 pulses per hour so I guess maybe three orders of magnitude
improvement in timing, or roughly microsecond accuracy. It needs
tens of nanoseconds accuracy to be comparable to ranging data
which achieves tens of metres.

I understand that the best ground based observations (with large
antennae) can achieve timing precisions of about 0.001 of a pulse
cycle. Unfortunately there are no "millisecond" pulsars with periods
of 1 millisecond or less. On the other hand, millisecond radio pulses
are typically quite sharp. On the third hand, any kind of
spin-stabilized spacecraft will be a pretty poor pulsar receiver,
since there would be no feasible way to use focussing optics that I
can see.

Craig

Craig Markwardt wrote:
"George Dishman" writes:
"Craig Markwardt" wrote in message
...
"Jeff Root" writes:
On the other hand, I wonder if you noticed that Max
specified "to Neptune and *back*"?

...

OK, I didn't notice that, and it makes the job much, much harder. I'm
not even sure it could be done. An orbit with perihelion at earth and
aphelion at Neptune has a period of about 60 years. I'm not sure if
gravity assist could be used, and of course the re-capture near earth
would be a major task.

Max's idea is to confirm that the anomaly changes direction
on an inward trip so to minimise systematics the plan would
be to launch on a fast, near radial trajectory out to say
Neptune, and then use a slingshot to bring the craft back
towards the Sun.

That would be quite a difficult bit of maneuvering!

Yep, I don't think he has got as far as considering how a
two way trip would be done.

Re-capture would be unnecessary, all that's needed is a long
enough baseline to determine the anomaly on each leg. The
essential feature would be to have both Doppler and ranging
so that the two could be compared to eliminate or confirm
non-dynamic effects, i.e. things affecting the signal rather
than the craft.

That isn't too hard to envisage if all that is being flown is
a spin-stabilised transponder. The simplest craft might be
nothing more than a large corner reflector with just enough
thrusters to do a course correction and some autonomous
navigation facility, you wouldn't even need to communicate
with it.

Well begging to differ, but I think that having thrusters is probably
anathema to a sensitive anomaly measurement, especially autonomous
thrusters :-)

Oh sure, I'm only thinking of a course correction good enough to
get the craft targetting the Neptune well enough for the slingshot
to be possble. Small corrections at either end with maybe 90%
in coast mode would be the idea, but I don't think such a mission
would have any value anyway, it's not a serious idea.

My previous point was that NASA gets a lot of competitive proposals
for missions, and it will be hard to get a "bare-bones" mission ranked
more highly than other missions, given the high fixed costs of each
planetary mission.

I entirely agree, that was what I was saying to Max.

My own thoughts on a mission have been on the lines of flying
a craft capable of receiving millisecond pulsar signals from
a number of sources simultaneously (using a synthetic aperture
technique) and using them like GPS to work out the location
and highly accurate timing on-board. Add an ensemble of atomic
clocks and you can measure and map the solar gravitational
potential by comparing the clocks to the pulsars to determine
the gravitational frequency shift. The self-determined location
could be radioed back and compared with the range and integrated
Doppler. It's a bit more expensive than the simpler reflector
but mapping the potential well of the Solar System might have a
chance of being seen as a new observation that could attract
some funds.

The problem I see with that is getting the timing resolution
from the pulsars. Pulse durations are quite large even for the
fastest repetition rates but on the other hand you get continuous
reception 24h a day. A 'millisecond' pulsar gives on the order of
10^6 pulses per hour so I guess maybe three orders of magnitude
improvement in timing, or roughly microsecond accuracy. It needs
tens of nanoseconds accuracy to be comparable to ranging data
which achieves tens of metres.

I understand that the best ground based observations (with large
antennae) can achieve timing precisions of about 0.001 of a pulse
cycle. Unfortunately there are no "millisecond" pulsars with periods
of 1 millisecond or less. On the other hand, millisecond radio pulses
are typically quite sharp.

The difference would be that ground based antennas have
limited time when the pulsar is above the horizon and of
course atmospheric effects and domestic RFI play a part,
but I wouldn't have thought much better than that could be
achieved in space.

On the third hand, any kind of
spin-stabilized spacecraft will be a pretty poor pulsar receiver,
since there would be no feasible way to use focussing optics that I
can see.

My thoughts were based on using a large near-spherical
structure like a C60 molecule with each facet being a fine
mesh ground plane with a small dipole and using a multi-
channel synthetic aperture technique to create a capture
area close to the diameter of the sphere. The craft wouldn't
need to spin, just be aware of its orientation and adjust the
phase of the antenna feeds accordingly. In fact the phase
could also be used to measure the orientation.

The same technique in reverse could be used to beam-form
the telemetry signal back to Earth, though choosing the
operating frequency would become a compromise.

Typically pulsars seem to need tens of metres of dish
diameter for good reception so facets of the order of a metre
or two would be needed giving frequencies in the 100MHz
to 1GHz range, maybe 408MHz?

http://zuserver2.star.ucl.ac.uk/~apo.../ap971214.html

http://www.georgedishman.f2s.com/astronomy/408MHz.png

The fun engineering challenge is to launch the craft "flat-pack"
and have the sphere deploy in space ;-)

George