Hi all
I have recently found this nice color image of Pioneer 5, which shows some mysterious blue cylinders on the solar panels, that I have never seen in any other picture. Any idea of what they may be?

I don't have a CLUE what they are - but I'll have a few guesses...

Attachments for cables to test array deployment in 1G environment.
Launch restraint bolts.
An instrument of some king for Mag etc?
They look a little like the sort of motors we see all over the MER's - but I don't think they would be that.

Doug

Without knowing the answer, I strongly suspect magnetometer coils, though I have a very very vague recollection that they only got mag field parallel and perpendicular to the spin axis.

The Pioneer 5 magnetometer is usually said to be mounted on the instrument deck on the inside of the sphere (which caused data to be quite garbled).
I think that they are some kind of solar panel extension dampers, but I am not sure

I'm inclined to agree. The first spacecraft to get REALLY good interplanetary field data were the Interplanetary Pioneers (6-9) and Mariner 10. Previous missions like Mariners 2, 4 and 5 had headaches separating spacecraft magnetic fields from the weak solar field. Building a "Magnetically Clean" spacecraft is a pain, and is expensive. Mariner 10 cheated. They installed two magnetometers, one halfway out the magnetometer boom, the other at the end of the boom. Comparing the two sets of readings reduced the spacecraft field interference to a small fraction of the solar wind's field.

Paolo:

They certainly look like pistons, whether used as dampers or during deployment.


Bob Shaw

this image
http://upload.wikimedia.org/wikipedia/en/d/db/Pioneer_5.jpg
Of P5 atop its LV without those features would suggest they're in the 'remove before flight' catagory.

This may only be a coin, but it doesn't have them either
http://www.farthestreaches.com/images/pioneer5f.jpg

Not sure if this is a model - but they're not here either
http://astro.zeto.czest.pl/sondy/pioneer5.jpg

Doug

Maybe they are some kind of handle for moving the solar panels?

Look like those silicone caulk dispensers to me.

Airbag

I looked at Explorer 6, which closely resembles Pioneer 5, but it does not have
those blue cylinders, either.

http://nssdc.gsfc.nasa.gov/planetary/image/explorer_6.jpg

http://www1.cira.colostate.edu/ramm/hillge...rer-6_image.jpg

http://www1.cira.colostate.edu/ramm/hillge...er-6_cover3.jpg


Two more Pioneer 5 images:

http://www1.cira.colostate.edu/ramm/hillge...eer-5_image.jpg

http://www1.cira.colostate.edu/ramm/hillge...er-5_image2.jpg

We all forgot that yesterday was the 50th anniversary of the launch of Pioneer 5, the first true interplanetary probe