Pioneer missions & one last attempt to contact P10.

**Analoguesat** · 20-01-2006

Older members will remember the Pioneer 10 & 11 missions - shot out into space in the mid 1970's they returned the first close up pics of Jupiter.

They were tracked and monitored until 2002 with occasional success in downloading telemetry from 10. Increasing distance (P10 is 87AU out now) and the slow decay of the nuclear reactors on board led to the last attempt at contact in 2003 failing.

P10 was tracked for 7.6 billion miles(!) and has now travelled 8 billion miles and it travelling at over 27000 mph......

_http://spaceprojects.arc.nasa.gov/Space_Projects/pioneer/PNhome.html

There will be one last effort on March 6th to contact Pioneer 10 and this really is the last chance - the spacecraft trajectory will soon mean that the antenna is no longer pointing at the Earth.

_http://www.planetary.org/programs/projects/pioneer_anomaly/update_200511.html

Incredible all but one of the earlier Pioneers which were launched in the mid 1960's were nominally partially operational into the mid 1990's

Pioneer 6-9
Pioneers 6-9 were launched into Solar orbit between 1965 and 1968. Their prime mission completed years ago, the spacecraft were then tracked only occasionally.

Pioneer 6 was launched on 16 December 1965. Some time after 15 December 1995 (almost 30 years after it was launched) the primary transmitter (TWT) failed. During a track on 11 July 1996 the spacecraft was commanded to switch to the backup TWT, and the downlink signal was re-acquired. The spacecraft and a few of the science instruments were again functioning.

Pioneer 6 was featured on the Star Date radio broadcast by the University of Texas McDonald Observatory on 16 December 2000 - the 35th anniversary of its launch. Pioneer 6 is the oldest NASA spacecraft extant. There was a successful contact of Pioneer 6 for about two hours on 8 December 2000 to commemorate its anniversary.

Pioneer 7 was launched on 17 August 1966. It was last tracked successfully on 31 March 1995. The spacecraft and one of the science instruments were still functioning.

Pioneer 8 was launched on 13 December 1967. Its primary TWT failed several years ago, but on 22 August 1996 the spacecraft was commanded to switch to the backup TWT, and the downlink signal was re-acquired. The spacecraft and one of the science instruments were again functioning.

Pioneer 9 was launched on 8 November 1968. The spacecraft failed in 1983.

spiney · 20-01-2006

remember this?

Oh heck - lets edit that link to this

Coz that does weird things to my screen

spiney · 20-01-2006

Fair enough, thanks Analoguesat!

(usually, I check the link works ok, but didn't quite have enough time here, apologies!).

**Analoguesat** · 20-01-2006

No problem - I did the same thing earlier this week & one of the other mods had to alter it

spiney · 20-01-2006

Yeah, any of us can trip up and fall over (bang, crash, laughter ......).

However, the replacement link, doesn't that say it changes daily (or have I misunderstood)?

**Channel Hopper** · 20-01-2006

One has to wonder what time the clock on board says, compared to that on Earth.

And of course New Horizons will overtake it in a matter of fourteen years or so.

spiney · 22-01-2006

OK, thanks Analoguesat, your replacement link seems fine, maybe I misunderstood about it changing daily .....

That "Pioneer plaque" occasioned much mirth and sarcasm, I remember! OK, the pulsars diagram is a good idea, that would locate Earth (but do we want "them" coming "here"?). Not so sure about the figures, maybe ET will think that's what we eat ......

**Analoguesat** · 22-01-2006

Originally Posted by spiney

OK, thanks Analoguesat, your replacement link seems fine, maybe I misunderstood about it changing daily .....

That "Pioneer plaque" occasioned much mirth and sarcasm, I remember! OK, the pulsars diagram is a good idea, that would locate Earth (but do we want "them" coming "here"?). Not so sure about the figures, maybe ET will think that's what we eat ......

I just parsed the link onto the word "here". Due to the length of the original link it pushed all the margins way out of line

spiney · 24-01-2006

Anyway, whatever, the problem of sending/receiving data from distant spacecraft is the same - in principle - as digital tv !!!

Convolutional codes are used, so a limited number of "already known" data words can assessed for "reception probability". In digital tv, that's same as "outer coding". "Inner coding" isn't used for spacecraft, (I think!), because we don't want to transfer lots of numeric data using "wasteful" (!) CRC codes, just receive from as far away as possible!

As spacecraft gets further away, within a power-limited bandwidth-limited communications channel, it's possible to keep slowing down the data transmission speed, to keep "received error" probability low, until the Shannon "minimum rate" is finally reached, after which the link finally fails!

See: http://deepspace.jpl.nasa.gov/techno...5_20/95-20.pdf , especially fig 10.

**Analoguesat** · 24-01-2006

Ah I can see it now - "Pioneer 10 TV" - the ultimate DX signal!

**Channel Hopper** · 24-01-2006

Originally Posted by spiney

See: http://deepspace.jpl.nasa.gov/techno...5_20/95-20.pdf , especially fig 10.

That link seems to have gone out of range

The Shannon limit is based upon an equation that includes time, and you can of course get all the info you need within an infinite number of seconds.

I studied this in depth (sic) during college, but it was yonks ago. Will try to find some updated stuff - Semantec rings a bell though, as the new idea behind data retrieval , and a few SciFi techi terms.

spiney · 26-01-2006

Sorry, channelhopper! I tested the link again, and it worked, but is a large pdf file from a slow link, and may fail on non-wideband connections.

Basically, it's about updating the NASA "deep space network", especially to keep contact with the distant robotic probes. FIg 10 just shows a trolley full of 19 inch rach mounted stuff, this being a new receiver for improved reception.

**Analoguesat** · 06-03-2006

Well today was the final attempt to contact Pioneer 10 - I wonder if they got anything?

**Channel Hopper** · 06-03-2006

http://www.planetary.org/programs/pr...te_200603.html

Any data will probably take a week or so to sift from the background noise.

**Analoguesat** · 30-03-2006

Well nothing seems to have been announced so I think we can safely say Pioneer 10 is now just so much intergalactic garbage heading off to Aldebaran in Taurus

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