Pioneer Anomaly, still?

[Enthalpy]

Sensei mistook W for W/m². I politely corrected the claim. Is that worth two negs?

 

If this computation needs an explanation:

Sunlight power density is a mean 1367W/m² at one AU (=Sun-Earth distance), hence 0.838W/m² at 40.4AU.

The craft exposes to sunlight its D=2.74m antenna (5.90m²) and the RTG (5% of the antenna's surface), together 6.19m².

The incoming sunlight (my original wording) on this area at 40.4AU is 5.2W.

The Pioneer Anomaly: an inconvenient reality or NASA‟s 12 year misconception? http://arxiv.org/ftp/arxiv/papers/1307/1307.0537.pdf

 

Done, thanks! Though, this paper brings little scientific material, it's more a compilation of what other people say.

But it's nice to know than Anderson, the maint author of the 1998 paper to which Turyshev contributed, disagrees with Turyshev's 2012 claim that thermal recoil would explain the anomaly.

[Bjarne]

Sensei mistook W for W/m². I politely corrected the claim. Is that worth two negs?

 

If this computation needs an explanation:

Sunlight power density is a mean 1367W/m² at one AU (=Sun-Earth distance), hence 0.838W/m² at 40.4AU.

The craft exposes to sunlight its D=2.74m antenna (5.90m²) and the RTG (5% of the antenna's surface), together 6.19m².

The incoming sunlight (my original wording) on this area at 40.4AU is 5.2W.

 

Done, thanks! Though, this paper brings little scientific material, it's more a compilation of what other people say.

But it's nice to know than Anderson, the maint author of the 1998 paper to which Turyshev contributed, disagrees with Turyshev's 2012 claim that thermal recoil would explain the anomaly.

Right, I notice the same, and this is maybe the most obvious place the conclusion could be wrong.

I am also wondering, as you, - if we can be on the threshold to new physic, this anomaly should be further tested.

It should be pretty easy to test radiation from all possible angles, from a similar space craft, - in a lab.

To be able to understand whether the radiation could have such impact like the lasts NASA report concludes.

I mean it only require a similar construction (and temperatur) to detect how isotropic or anisotropic the radiation really is / was.

It should off course be possible to test for much less than sending out new spacecraft, as you suggested.

[Sensei]

Sensei mistook W for W/m². I politely corrected the claim. Is that worth two negs?

 

If this computation needs an explanation:

Sunlight power density is a mean 1367W/m² at one AU (=Sun-Earth distance), hence 0.838W/m² at 40.4AU.

The craft exposes to sunlight its D=2.74m antenna (5.90m²) and the RTG (5% of the antenna's surface), together 6.19m².

The incoming sunlight (my original wording) on this area at 40.4AU is 5.2W.

 

Enthalpy, if you don't want to introduce misunderstanding you should always provide calculations in Latex, so everybody can follow it step by step. We're not reading in your mind.

Antenna has no area 5.9 m²

because it's not flat surface (circle area with radius r=1.37m), but has depth 46 cm, so it's actually cone.

Area of such cone, without base, is

[math]A=\pi*r*\sqrt{r^2+h^2}=\pi*1.37*1.4451643505=6.2199612583 m^2[/math]

 

Another thing is that antenna is not pointing at the Sun, but to the Earth, as it's sending and receiving data to/from us.

 

Yet another thing is that anomaly just started at distance ~40 AU. And then is continuing to 67 AU and further.

While light from the Sun is dramatically decreasing.

 

[michel123456]

 

Enthalpy, if you don't want to introduce misunderstanding you should always provide calculations in Latex, so everybody can follow it step by step. We're not reading in your mind.

Antenna has no area 5.9 m²

because it's not flat surface (circle area with radius r=1.37m), but has depth 46 cm, so it's actually cone.

Pioneer Antenna.png

Area of such cone, without base, is

[math]A=\pi*r*\sqrt{r^2+h^2}=\pi*1.37*1.4451643505=6.2199612583 m^2[/math]

 

Another thing is that antenna is not pointing at the Sun, but to the Earth, as it's sending and receiving data to/from us.

 

Yet another thing is that anomaly just started at distance ~40 AU. And then is continuing to 67 AU and further.

While light from the Sun is dramatically decreasing.

 

I really wonder what Enthalpy will respond but:

_I think that the surface of the cone doesn't matter, what matters is the diameter. If you were to calculate the amount of rain instead of photons, you wouldn't receive more water because it is a cone.

_Also if you draw a sketch to scale of the sattelite-Earth-Sun combination, it may result that the Sun is so huge and the Earth so small, so that your remark about the antenna pointing to the Earth has no importance at all, in fact at 40 AU the antenna is always roughly pointing to the Sun (I think).

Edited December 6, 2014 by michel123456

[Sensei]

I really wonder what Enthalpy will respond but:

_I think that the surface of the cone doesn't matter, what matters is the diameter.

More precisely it's not cone but something like this:

 

Cone had 5.45% bigger area than flat circle area.

Satellite dish will have even higher difference in area.

 

Once we have area, we can calculate normal vectors of that curved surface and use it to calculate Sun's emitted/absorbed energy.

Flat circle area would have normal vector pointing directly to Sun. But antenna has curved surface.

 

_Also if you draw a sketch to scale of the sattelite-Earth-Sun combination, it may result that the Sun is so huge and the Earth so small, so that your remark about the antenna pointing to the Earth has no importance at all, in fact at 40 AU the antenna is always roughly pointing to the Sun (I think).

Satellite dish is very picky about rotation. It's directional antenna.

I have such for Hot Bird satellite. It must be very precisely adjusted (and I hate doing this!)

1mm difference in any axis, and there is no signal. It has 4.6 times smaller diameter than Pioneer. But Hot Bird is much closer to us.

 

Make right triangle with a=40.4 and b=1. And calculate angle.

Angle is -1.44 degrees at one moment, and +1.44 degrees half year later, when Earth is on opposite side of its orbit.

[Enthalpy]

It's the projected antenna's area that count. Cone, parabola.. don't chance anything.

 

At 40AU, pointing to Earth instead of the Sun multiplies by cos(1/40 rad) or 0.9997: who cares.

[Bjarne]

New Horizons wakes up for historic Pluto encounter

 

New Horizons woke up from hibernation on December 6, 2014 after a 4.8 billion km voyage (3 billion miles) and almost nine years after launch. The spacecraft is now preparing for a six-month encounter with Pluto that begins in January 2015.

http://thewatchers.adorraeli.com/2014/12/08/new-horizons-wakes-up-for-historic-pluto-encounter/

So when do we get the trajectory anomaly news ?
Before newyear ?
I think so..

Acelerating or decelerating space prove anomaly ? - Starting after or before Jupiter fly by ? - Easy.

 

 

My nick name is Silencio, it have to be

Edited December 9, 2014 by Bjarne

[Bjarne]

There are two features of the anomaly, as originally reported, that are not addressed by the thermal solution: periodic variations in the anomaly, and the onset of the anomaly near the orbit of Saturn.
First, the anomaly has an apparent annual periodicity and an apparent Earth sidereal daily periodicity with an amplitude greater than the error budget.[36] However, the same paper also states this problem is most likely not related to the anomaly: "The annual and diurnal terms are very likely different manifestations of the same modeling problem. [...] Such a modeling problem arises when there are errors in any of the parameters of the spacecraft orientation with respect to the chosen reference frame."

Source http://en.wikipedia.org/wiki/Pioneer_anomaly

 

Does anybody have more info about the values of the annual variations?

Edited December 10, 2014 by Bjarne

[Bjarne]

I read som time ago (but forgot where) that there is also a seasonal anomaly in the data, - can someone firfirm that ?