Posted on 03/02/2007 4:30:53 PM PST by blam
Computer sleuths try to crack Pioneer anomaly
19:24 02 March 2007
NewScientist.com news service
Stuart Clark
Because the tracking system for the Pioneer probes changed so much since their launches in the early 1970s, researchers have to look at each data file individually to put them in the same format (Image: NASA/ARC)
Scientists and engineers remain on course in their efforts to determine what caused the twin Pioneer spacecraft to apparently drift off course by hundreds of thousands of kilometres during their three-decade missions. Within a year, they expect to be able to decide whether this drift was caused by a fault on the spacecraft.
Launched 35 years ago on Friday, Pioneer 10 was the first spacecraft to reach the outer Solar System and return pictures of Jupiter. It was followed by Pioneer 11, which launched on 5 April 1973 and also visited Saturn.
After these historic encounters, NASA kept track of the drifting spacecraft, finally losing contact with Pioneer 11 in 1995 and Pioneer 10 in 2003.
The so-called Pioneer anomaly showed up in the tracking data as a tiny deceleration for both spacecraft, even though they were heading in different directions. It was as if the Sun’s gravity was pulling a little harder than Newton’s laws predicted (see 13 things that do not make sense).
Escaping heat
The source of the deceleration has long been suspected to be heat escaping from the small nuclear generators onboard, known as RTGs (Radioisotope Thermal Generators). Previous analyses that claimed to rule out this effect have been contested.
(Excerpt) Read more at space.newscientist.com ...
Anyone think about the simple answer... they've both been picking up mass in the form of dust and particles for 30 years... variations in the particle density on the way through the solar system could easily have caused the drift.
Tech support keeps telling them, "Please for to be reobooting your computer, sir..."
Hi Alamo Girl:
Would an adjustment to the fine structure constant account for a slight increase in gravitational pull?
Easy...Bush's Fault!
I was going to say that the solar wind over time could blow them off course. I suppose that after time your gravity or electrical charge would pick up debris. Wonder if they accounted for either.
You're a Great American.
Oh great,
now were polluting outer space. Where's Gore!
thats--just--disturbing....
At the speed those thingas are going, wouldn't the dust just blow off?
Friction/resistance=de-acceleration. Space isn't totaly empty! Almost, but not quite.
microgravity would allow substantial amounts of material to accumulate under the right conditions.
Very interesting.
That would explain my need to buy larger pants sizes every few years...
.....global warming..?
In a word - no.
However, that is not the case here. This pops up off and on about every two years here. :-)
This was noted long before that.
that was easy ;-)
It's natural for the spacecraft to slow down. It's been a long green flag run, the tires are worn down, the track is cooling & they're getting a little loose off the corners. Time to pit for new rubber.
The world does revolve around you.
ah, but those variables were a known quantity, and part of the programed trajectory.
in her presence!My uncle worked on a portion of the power system for the Pioneer probe.
Who needs space? The heavenly body has descended.
Nice Pic.
We would see torques on the vehicle itself if the dust was thick enough to cause a delta-V. Also the instruments would have detected said dust.
Not with the mass of the probes nor the short time involved.
At these masses and velocities, the fine structure constant is just that. A constant.
Cool. I was in the Voyager control room during the Neptune flyby.
I taped the PBS special on Neptune at Night and would actually watch it when I came home after work. What was it, 20 minutes between new pictures being shown?
My kids used to bring friends over just to laugh at their crazy old man.
What a difference in generations.
Speaking of which, as of now, (04:47 UTC 3/3/2007), Voyager 1 is 102.03 AU from Earth, and 102.00 AU from the sun.
Voyager 2 is 82.619 AU from Earth and 82.112 AU from the sun.
Click HERE for what the solar system would look like from VGER1 if you could see the orbits of the planets from there...
To give an idea of how far Voyager 1 has travelled, consider that Pluto is currently 31.356 AU from Earth, and 31.273 AU from the Sun.
Wow! How cool. :-) Glad you enjoyed!!!! Whoohoo
We used to watch the pictures being built pixel by pixel as the data streamed in and was decoded.
Indeed it is. I have the original papers on this. I need to dig them out.
Possible explanations:
Explanations for the discrepancy that have been considered include:
observational errors, including measurement and computational errors, in deriving the acceleration
Approximation/statistical errors
a real deceleration not accounted for in the current model, such as:
gravitational forces from unidentified sources such as the Kuiper belt or dark matter
drag from the interplanetary medium, including dust, solar wind and cosmic rays
gas leaks, including helium produced by radioactive decay escaping from the spacecrafts' radioisotope thermoelectric generators (RTGs)
radiation pressure of sunlight, the spacecraft's radio transmissions, or thermal radiation pressure from the RTGs (See Radioisotope rocket)
electromagnetic forces due to an electric charge on the spacecraft
new physics
clock acceleration (gr-qc/0410084) between coordinate or Ephemeris time and International Atomic Time.
A modification of the law of gravity. The theory known as MOND (MOdified Newtonian Dynamics), states that the force of gravity deviates to a very different force law at very low accelerations of order: 10−10 m/s2from the traditional Newtonian value.
I was not calling you stupid. I did not have heaps of time to write a dissertation here. I have discussed this at length with some of the principal investigators and was relaying quick answers.
My apologies
That I can accept. Thanks.
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