New Theory About the Source of Pioneer Space Probe Deceleration

First time accepted submitter deathcow writes "After forty years, a fresh perspective on old Pioneer data leads to new conclusions as to why the Pioneer probes are decelerating. Many theories to the slowing probes have persisted over the years — was it gravity? some type of unforeseen radiation? dark matter? Thanks to the data backup preservation efforts of a NASA Ames Research engineer, mountains of old telemetry data were still available for studying this curious anomaly."

Regardless - the science is fascinating

[blanchae]

The design of these spacecrafts is simply amazing. No wonder the US was the technological marvel of the world at the time. Considering the tools that were available then and the thought that was put into the effects of space on the motion, is mind boggling. Not to mention a power source that will last 88 years and the fact that they are still going and communicating while using a 1 bit camera to create fantastic pictures. I am humbled. The technology that was created and developed as a side effect of this monumental tasks is what made the US a technology giant. We need more of this positive vision and less of the negative sabre rattling.

Re:I hate IEEE Spectrum

[tloh]

I too, stopped reading Spectrum a few years ago when real science article dropped to a trickle. However, this particular article is not bad. Not only was it authored by one of the original problem solvers, it was very readable despite the length. I was intrigued particularly by their description of how they modeled the craft. It struck me as they described having to contend with blueprints rather than CAD files and consulting retired engineers from the original mission, that they appeared to have forgotten there is a very nice physical model of the craft hanging from the ceiling of the Smithsonian:

http://en.wikipedia.org/wiki/Pioneer_H [wikipedia.org]

I'm sure given the stakes involved (the real likely hood of discovering exotic physics) they wouldn't have minded taking the "replica" down for examination.

Re:Article too long, let me save you some time

[bostonsysadmin]

Seriously... it is just so laughably insane. If you were to tell someone from even just the 1940s that we would have an object doing this and that we could measure its progress to an incredible degree of precision, they would laugh at you and think that you were insane. Seriously... how is there still religion in this world? JFC... wake up already.

Here's something sad

[argStyopa]

....the entire mission cost -all the years in total - for Pioneer 10 was approximately $350 million (2001) USD. (It'll reach Aldebaran in about 2 million years.)

That's a little bit under a single week of NASA's budget this year. ($19bill) ...or about 4 hours of the Defense budget ($677 bill) ...or about an hour of the Social Security+Medicare budgets ($1.92 trillion).

Thermal force

[Geoffrey.landis]

It's thermal recall force from heat generated by components on Pioneer.

Right. and the headline is a little misleading, it's a "new" explanation only if you weren't following; since it was announced in late 2010. The "anomaly" is solved.

Popular Science article about Toth and Turyshev's work here: http://www.popsci.com/pioneeranomaly [popsci.com]

More detailed calculations supporting the explanation:
Phys Rev Letters paper by Toth and Turyshev here: http://prl.aps.org/abstract/PRL/v108/i24/e241101 [aps.org]
ArXIV paper confirming the work with more details: http://arxiv.org/abs/1103.5222v1 [arxiv.org]

JPL press release: http://www.jpl.nasa.gov/news/news.php?release=2012-209&cid=release_2012-209&msource=12209 [nasa.gov]
Centauri Dreams article: http://www.centauri-dreams.org/?p=23720 [centauri-dreams.org]

Still, it's a nice article to read about how the work is done.

Re:Article too long, let me save you some time

[wvmarle]

That is 55 ms on some 16 hours, seven orders of magnitude less. And it's not measured by round trip, but by Doppler effect.

Then the calculations to where it is expected to be are so mighty accurate that we can actually know that this is an anomaly, and not within error. To be able to calculate where the craft should be, you must know very accurately the gravitational constant, the masses of the Sun and the respective planets, effects of the solar wind pushing the craft out (actually that's what they were trying to measure as well), the speed of the Earth relative to Voyager, and probably some relativistic effects. Probably I missed some variables that have to be taken into account here. That overall accuracy is simply mind boggling as there are so many variables involved that with the slightest error in some of them, you end up with a much larger error in the final result.