Flyby Anomaly Mystery Deepens

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alexjrgreen
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Post by alexjrgreen »

Excellent. The bug fix worked.
Ars artis est celare artem.

MSimon
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Post by MSimon »

The effect they are seeing is in the parts per million range.
Engineering is the art of making what you want from what you can get at a profit.

DeltaV
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Post by DeltaV »

http://arxiv.org/PS_cache/arxiv/pdf/090 ... 4184v1.pdf

"Multiple experiments performed by different teams using a variety of spacecraft have firmly
established the existence of an anomalous effect during Earth flybys. The cause of this effect
remains unknown. Lammerzahl et al. (2006) have considered, and dismissed, a variety of
possible conventional causes, including effects due to the atmosphere, tides, electric charge
and magnetic moment of the spacecraft, radiation pressure due to the Earth’s albedo, solar
wind, and spin-rotation coupling. Antreasian and Guinn (1998) have earlier dismissed
explanations involving the Moon, the Sun, and relativistic effects."
...
"By 2009, the existence of the flyby anomaly has been confirmed by a variety of teams
with several spacecraft.While it is unlikely that the origin of the flyby anomaly will prove to
be anything other conventional in nature, because of its importance for high-precision navigation
further investigations into the physics of this puzzling effect are certainly justified."

IntLibber
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Joined: Wed Sep 24, 2008 3:28 pm

Post by IntLibber »

DeltaV wrote:http://arxiv.org/PS_cache/arxiv/pdf/090 ... 4184v1.pdf

"Multiple experiments performed by different teams using a variety of spacecraft have firmly
established the existence of an anomalous effect during Earth flybys. The cause of this effect
remains unknown. Lammerzahl et al. (2006) have considered, and dismissed, a variety of
possible conventional causes, including effects due to the atmosphere, tides, electric charge
and magnetic moment of the spacecraft, radiation pressure due to the Earth’s albedo, solar
wind, and spin-rotation coupling. Antreasian and Guinn (1998) have earlier dismissed
explanations involving the Moon, the Sun, and relativistic effects."
...
"By 2009, the existence of the flyby anomaly has been confirmed by a variety of teams
with several spacecraft.While it is unlikely that the origin of the flyby anomaly will prove to
be anything other conventional in nature, because of its importance for high-precision navigation
further investigations into the physics of this puzzling effect are certainly justified."
The problem is they treat it as a three body problem between the spacecraft, the Earth and the Sun, when actually the Moon is involved which gives a bit of angular momentum up tidally to the spacecraft.

DeltaV
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Joined: Mon Oct 12, 2009 5:05 am

Re: Flyby Anomaly Mystery Deepens

Post by DeltaV »

Earth flyby of Juno spacecraft today.

http://www.lpi.usra.edu/opag/jul2013/pr ... _plans.pdf
Juno Gravity Science at Earth Flyby

• Most Earth fly-bys exhibit an unexpected energy gain change
– Equivalent to a maneuver of a few mm/s
– Easily detected in comparing 2-way Doppler data before and after flyby

• Cause of energy gain is unknown
– Most likely due to error in gravity models applied to hyperbolic orbits
– But might be some non-gravitational force not modeled

• Juno will gather unique data to investigate flyby anomaly
– Continuous DSN tracking for 7 days centered on periapsois, except for gap from 2.25 hours before periapsis to 1.5 hours after periapsis
– ESA tracking from 2.25 hours before periapsis to 7 minutes before periapsis and from 20 minutes after periapsis to 1.5 hours after periapsis
– Juno IMU (Inertial Measurement Unit) will be on during flyby, including accelerometers which can measure non-gravitational forces large enough to cause anticipated anomaly

Stubby
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Re: Flyby Anomaly Mystery Deepens

Post by Stubby »

Glad to know you knew where this thread was and that the shock paddles were still fully charged :D :D
Everything is bullshit unless proven otherwise. -A.C. Beddoe

DeltaV
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Re: Flyby Anomaly Mystery Deepens

Post by DeltaV »

T-P search worked this time. Maybe Joe has been tinkering.

GIThruster
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Re: Flyby Anomaly Mystery Deepens

Post by GIThruster »

I went to look up NASA's Copernicus program but the web site is down because of the intention to generate maximum pain.

In any event, I doubt it is true the flyby deviation is from neglecting the Moon. Copernicus is a GR treatment of multiple bodies on any flight path. NASA would not "forget" to factor in the Moon.

We had these deviations with the Pioneer spacecraft as well and they were not flying by but simply leaving after a slingshot maneuver. It does appear our model of gravity is not yet complete.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

Schneibster
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Re: Flyby Anomaly Mystery Deepens

Post by Schneibster »

DeltaV wrote:Earth flyby of Juno spacecraft today.
Have you ever heard of Gravity Probe B?

Now what anomaly was that, precisely?
We need a directorate of science, and we need it to be voted on only by scientists. You don't get to vote on reality. Get over it. Elected officials that deny the findings of the Science Directorate are subject to immediate impeachment for incompetence.

DeltaV
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Re: Flyby Anomaly Mystery Deepens

Post by DeltaV »

There's a new invention out, "Google".

Schneibster
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Location: Monterey, CA, USA

Re: Flyby Anomaly Mystery Deepens

Post by Schneibster »

DeltaV wrote:There's a new invention out, "Google".
OK, well, it appears you've never read about it.

Do so. I will point out there's no mention of a "flyby" effect on Gravity Probe B. And all it did was "flyby" the Earth for its entire lifetime.

After which provide evidence that this "flyby" effect is compensated for in the GPS network. GPS satellites essentially "flyby" the Earth continuously.

After which provide evidence that the spacecraft, Juno, was knocked into "Safe" mode by this anomaly.

Remember the "Pioneer Anomaly?" Turned out to be due to radiation pressure from its heat emissions, miscalculated the first time around, and confirmed by most of the original "discoverers." Red faces over that one.
We need a directorate of science, and we need it to be voted on only by scientists. You don't get to vote on reality. Get over it. Elected officials that deny the findings of the Science Directorate are subject to immediate impeachment for incompetence.

Schneibster
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Joined: Mon Jul 09, 2007 5:21 am
Location: Monterey, CA, USA

Re: Flyby Anomaly Mystery Deepens

Post by Schneibster »

One thing to keep in mind: yes, an "anomaly" happened.

No it wasn't "the flyby anomaly."

There is, wonder of wonders, more than one kind of anomaly.

Typical meshback science denier confusion.

Oh and BTW it's very unlikely the spacecraft even knows what its velocity is. There's no reason for the extremely crude robot brain on board to know; it's totally incapable of astrogation. It's not powerful enough. That's all done here and then commands are sent to it. So what exact anomaly is it you claim it detected?
We need a directorate of science, and we need it to be voted on only by scientists. You don't get to vote on reality. Get over it. Elected officials that deny the findings of the Science Directorate are subject to immediate impeachment for incompetence.

GIThruster
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Re: Flyby Anomaly Mystery Deepens

Post by GIThruster »

For those interested in how NASA does spacecraft trajectory design and thus also analyzes for trajectory anomalies, here's what you can read with NASA closed:

http://courses.ae.utexas.edu/ase333t/pa ... rnicus.pdf
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

paperburn1
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Re: Flyby Anomaly Mystery Deepens

Post by paperburn1 »

I don,t think the red faces were in NASA, more like the press hopping on the bandwagon of (your wrong). I think NASA take on the situation was "That's odd, what did we forget in our spacecraft trajectory model"
Don't we have someone here with an inside track on that....Maui?
I am not a nuclear physicist, but play one on the internet.

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