What's the deal with Pioneer 9/10 ?

Factual Questions
1

This thread seems to spoof someone’s belief that the Pioneer probes are behaving erratically.

However, NASA in this article seems to be telling us that they have permanently lost contact with the probes.

So, fight my ignorance! Are these probes gone from (current) technological reach? Or is NASA still physically tracking them?

If they are still tracking them, how? And what’s the Straight Dope about that? (Meaning of course:

  1. The probes are moving as expected
  2. They’re moving faster than expected
  3. They’re slowing down
    )

Links would be appreciated!

2

Without radio contact, there’s no way of detecting them any more. At those kinds of distances, you’re lucky to find a dwarf planet, much less a probe a few meters across.

Meanwhile, the Pioneer Anomoly (which has been known for rather a while, from back when we were still getting data from the probe) is apparently real, but it’s small enough that there are an awful lot of potential explanations which need to be ruled out before we can go changing the laws of physics.

3

[QUOTE=Chronos]
Without radio contact, there’s no way of detecting them any more. At those kinds of distances, you’re lucky to find a dwarf planet, much less a probe a few meters across.

Meanwhile, the Pioneer Anomoly (which has been known for rather a while, from back when we were still getting data from the probe) is apparently real, but it’s small enough that there are an awful lot of potential explanations which need to be ruled out before we can go changing the laws of physics.
[/QUOTE]

Thanks. Just to get it straight: We don’t get data from the probe(s) since around 2003?

And this site which reports the facts (breathlessly, in present tense) is not that trustworthy?

4

When in doubt, try Wiki… Pioneer anomaly - Wikipedia

5

Did I miss something here? What about Voyager 1 & 2? Didn’t they suffer the same anomaly? If not, what’s the explanation?

6

[QUOTE=user_hostile]
What about Voyager 1 & 2?
[/QUOTE]

The pioneers use spin stabilization, the voyagers use thrusters to maintain alignment.

From the wikipedia article linked above:

From the article, the acceleration is sunward, so they are slowing down.

7

For background, here’s a great article on Pioneer 10 from the Winter 2001 issue of Invention & Technology:
The Spacecraft That Will Not Die

The article predicted the loss of communication by 2002.

I found this bit about the PDP-11 quite intriguing:

8

[QUOTE=user_hostile]
Did I miss something here? What about Voyager 1 & 2? Didn’t they suffer the same anomaly? If not, what’s the explanation?
[/QUOTE]

Wiki addresses that:

9

[QUOTE=minor7flat5]
For background, here’s a great article on Pioneer 10 from the Winter 2001 issue of Invention & Technology:
The Spacecraft That Will Not Die

The article predicted the loss of communication by 2002.

I found this bit about the PDP-11 quite intriguing:

[/QUOTE]
Huh? Have they never heard of a cross-compiler?

Methinks the article writer misunderstood something.

10

[QUOTE=Punoqllads]
Huh? Have they never heard of a cross-compiler?

Methinks the article writer misunderstood something.
[/QUOTE]
Or there are a whole mess of other factors that were left out. The writers in that magazine are fairly thorough; it’s not Popular Science.

11

[QUOTE=Punoqllads]
Huh? Have they never heard of a cross-compiler?

Methinks the article writer misunderstood something.
[/QUOTE]

Is it possible that the control software was written in assembly? If that’s the case then the only options would be to emulate it or re-write the whole thing.