Talk:Flyby anomaly

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The Moon?

More speculation, but could this be due to the Earth's moon? —Preceding unsigned comment added by C.A.T.S. CEO (talk • contribs) 03:59, 17 October 2009 (UTC)[reply]

JPL's empirical formula and the Nov. 2007 Rosetta flyby

According to "Anomalous Orbital-Energy Changes Observed during Spacecraft Flybys of Earth" by John D. Anderson, James K. Campbell, John E. Ekelund, Jordan Ellis, and James F. Jordan[1], the authors made a prediction about the magnitude of the anomaly that Rosetta would experience during its November 13, 2007 flyby.

That was six months ago. By now, there should be some news about whether the predicion was accurate, but I haven't heard anything. Either way, it would be interesting. If you know something about this, please add it to the article.199.46.199.232 (talk) 21:46, 23 May 2008 (UTC)[reply]

No anomaly was observed during the last Rosetta flyby. —Preceding unsigned comment added by 145.238.204.239 (talk) 10:08, 27 May 2010 (UTC)[reply]

Indeed, no anomaly was observed during the 2009 Rosetta flyby. This doesn't contradict Anderson's equation, which predicted an anomaly smaller than 1mm/s. Lacking the data for the Rosetta flyby myself I can't perform the calculations to see just how wrong (or right) Anderson's formula is. I updated the article to say there was no anomaly detected, but made no mention of Anderson's formula (yet). Banedon (talk) 04:26, 10 March 2011 (UTC)[reply]

Cassini

The number for Cassini is incorrect. Cassini measured no effect, and they looked for it too. User:137:78:78:184 20:21 !9 August 2006

Date & IP address added for previous post. Wwheaton (talk) 20:52, 13 November 2009 (UTC)[reply]

Comparison to Pioneer anomaly

"Satellites" should be "space probes" or "spacecrafts". Also it doesn't seem right to claim that the Pioneer Anomaly is "very similar" - Pioneer Anomaly means change in acceleration while FA means change in velocity. Also we have no idea about causes, so they may be completely unrelated. Mandevil (talk) 14:30, 5 March 2008 (UTC)[reply]

How can you affect an object's velocity without affecting its acceleration? The two are, by definition, directly linked to each other.199.46.199.232 (talk) 21:46, 23 May 2008 (UTC)[reply]

Pure speculation on my part...

...But perhaps it has to do with the indications (recently mentioned on NOVA, on PBS) of a magnetic reversal soon to hit the planet within the next century. The magnetic field has been weakening, is the only extreme change I can see in Earth to cause a change in energy output and subsequent impact on incoming spacecraft. --Chr.K. 01:49, 12 November 2006 (UTC)[reply]

Units

What is 66mHz supposed to be- milli or mega? If the former it's so rarely used that it could usefully be specified explicitly. MarkMLl (talk) 14:44, 23 September 2008 (UTC)[reply]

Trajectories

Is it just me or is this still incomplete data in the table? I think the flyby trajectory angle around a sphere has two dimensions: towards equator (0 degrees should mean "following latitudes", 90 degrees "following longitudes", more than means backwards direction), and latitude of the perigee (where is the closest point), or alternatively angle of the perigee in the orbit plane vs. equator. We have the first parameter, but with the theory that it depends on inbound/outbound angle, we need the perigee latitude as well. Whoever has access to the paper with the current working hypothesis (it's just an equation, no explanation why) should be able to extract that from the paper. —Preceding unsigned comment added by Bernd Paysan (talk • contribs) 23:51, 10 January 2009 (UTC)[reply]

Flyby anomaly may be a radar anomaly

Eg See:

Resolving Spacecraft Earth-Flyby Anomalies with Measured Light Speed Anisotropy http://arxiv.org/abs/0804.0039

Doppler shift observations of spacecraft, such as Galileo, NEAR, Cassini, Rosetta and MESSENGER in earth flybys, have all revealed unexplained speed `anomalies' - that the doppler-shift determined speeds are inconsistent with expected speeds. Here it is shown that these speed anomalies are not real and are actually the result of using an incorrect relationship between the observed doppler shift and the speed of the spacecraft - a relationship based on the assumption that the speed of light is isotropic in all frames, i.e. invariant. Taking account of the repeatedly measured light-speed anisotropy the anomalies are resolved. The Pioneer 10/11 anomalies are discussed, but not resolved. The spacecraft observations demonstrate again that the speed of light is not invariant, and is isotropic only with respect to a dynamical 3-space. The existing doppler shift data also offers a resource to characterise a new form of gravitational waves, the dynamical 3-space turbulence, that has also been detected by other techniques. —Preceding unsigned comment added by 122.105.86.2 (talk) 12:06, 5 July 2009 (UTC)[reply]

This paper is not peer reviewed yet. None of the references for other measurements of an anisotropy of light speed is to a well-respected source. The explanation how this does not contradict special relativity theory sounds shady to me. I would not trust this paper, unless it gets published in a respected journal. I also found this: http://prl.aps.org/abstract/PRL/v60/i2/p81_1 The anistropy of light speed does not exist. —Preceding unsigned comment added by 134.36.15.74 (talk) 12:13, 18 January 2011 (UTC) (sorry I do not know the standard way to post a comment on this)[reply]

Error bars missing

The table lacks the 1-σ error intervals for row "Speed increment at perigee, mm/s" in columns Cassini, Messenger, Rosetta-II. Could someone please look them up? Thx Paradoctor (talk) 16:33, 22 November 2009 (UTC)[reply]

Thanks for the quick response, but I was talking about "increment at perigee". The values listed are "≈−0.2", "~0" and "~0", which is uninformative at best. Paradoctor (talk) 17:30, 22 November 2009 (UTC)[reply]

But one is easily derived from the other, since they are related by a common energy gain. For these small dvs, the delta V at perigee is equal to the delta V at infinity time the ratio (speed at infinity/speed at perigee). So these are easily computed from the other table entries. Also, the speeds at infinity and perigee are very well known, so the error bars are related in the exact same way. This can be verified by checking the other entries, where these relationships hold. So I updated the missing entries where the data is published. LouScheffer (talk) 00:47, 23 November 2009 (UTC)[reply]

"easily derived" assumes that one is aware of this relationship. I wasn't, and that's probably true for the vast majority of the ~100 readers each day. Besides, what good is a lookup table if you have to calculate the values yourself? ;) Aside from that,

Thank you for updating the table. Paradoctor (talk) 10:21, 23 November 2009 (UTC)[reply]

Need for more data

The table regarding the respective data of the fly-by satellites doesn't give any indication of the direction of approach regarding the earth's rotation. For instance was Cassini approaching from a 'retrograde' direction.

Also, there is no data as to the relative position and direction of the moon. Was our moon's varying gravitational influence assisting or reducing the probe's velocity?

Nick Summers —Preceding unsigned comment added by 80.175.186.68 (talk) 12:53, 22 January 2010 (UTC)[reply]

I'd also like to have more data, including relative position/direction to the sun. The full set of data should be fairly easy to give: point on earth's surface for the object's closest distance, distance and speed at that point, direction vs. equator, exact time and date, and of course the effect itself (delta in speed). The rest is then easy to calculate. --Bernd (talk) 20:53, 23 January 2010 (UTC)[reply]

You can try the JPL web interface to solar system and spacecraft data, at [2] .This is an interface into their navigation software, and can give you all the info you want, and much more. LouScheffer (talk) 21:28, 23 January 2010 (UTC)[reply]

Calculate Percentage Of Ferrous Metals To Check Against Spurious Magnetic Effect

I have a possible solution based on the spacecraft being affected by a magnetic effect which is emitted around the Earth's equatorial region. This idea can be easily checked relatively easily by adding the % of ferrous metals into the calculation, as well as the duration of equatorial transit. The NEAR spacecraft must have a higher percentage of ferrous metals compared to the others to give the greatest increase in energy w.r.t. distance above the surface of the flyby. A supermagnetic effect must be emitted from the Earth which is affecting the craft as they traverse the plane of rotation imo. The explanation for this is from solid metastable metallic hydrogen deposited by comets. More comets were deposited over time along the equatorial regions due to the effect of the Moon. Metallic hydrogen is a state of hydrogen which results when it is sufficiently compressed and undergoes a phase transition; it is an example of degenerate matter. Solid metallic hydrogen is predicted to consist of a crystal lattice of hydrogen nuclei (namely, protons), with a spacing which is significantly smaller than the Bohr radius. (Alan lowey)