Pioneer 11's 'near miss' at Saturn Options

[As old as Voyage...]

A couple of websites state that Pioneer 11 discovered a new moon of Saturn during its 1979 flyby and nearly collided with it.

http://www.uwgb.edu/DutchS/CosmosNotes/voyagr00.htm

The website says Pioneer 11 missed the previously unknown moon by only a few hundred km.

http://www.uwgb.edu/dutchs/planets/satslid.htm

Apparently the spacecraft inferred the moon's existance by the disturbances it created in Saturn's magnetic field.

Is this right? Did Pioneer 11 nearly end its mission in an unforseen Deep Impact style crash?

[belleraphon1]

Yes,

being older than Pioneer, I remember this and the Pioneer team even gave it an informal name....

quote from http://www.geocities.com/CapeCanaveral/Lau.../2099/9711.html

"Without warning, the outputs of several of Pioneer's radiation detectors suddenly plunged to nearly zero, held roughly steady for eight seconds, and then snapped back up to their former values. For the same eight seconds, the magnetometer recorded major disturbances in Saturn's magnetic field. Pioneer had streaked through the magnetic "wake" of a moon roughly 200 km across, at a distance of no more than a few thousand kilometers -- the closest it had come to any large object since leaving Earth. Later, the villain was tentatively identified as a moon discovered the previous day from Pioneer's imaging, and suspected from earlier observations by Earth-based telescopes. After the Voyager flybys, it became clear that there are two similarly-sized moons (now named Epimetheus and Janus) in the same orbit, and there is still some uncertainty about just which one was the object of Pioneer's near-miss. "

Will have to look up more references that do not exist online (books).

Craig

[dvandorn]

Yes,

being older than Pioneer, I remember this and the Pioneer team even gave it an informal name....

quote from http://www.geocities.com/CapeCanaveral/Lau.../2099/9711.html

The article doesn't give the informal name. Do you recall it? (I seem to recall the whole episode, but can't for the life of me remember the informal name.)

Good article, though -- especially as it's written by an old Usenet friend, Henry Spencer. As a proud virtual owner of several "I Corrected Henry" T-shirts from back in my Usenet days, I fondly recall his near-total and rarely-failing memory. (It's not true that I cribbed my writing style from Henry, though. When I encountered him on Usenet, I discovered that he and I have virtually identical writing styles -- another thing I enjoyed about him.)

-the other Doug

[GregM]

.

[belleraphon1]

If I recall correctly, it was dubbed "Pioneer Rock", and the gap between the "A" and "F" rings was called the "Pioneer Gap". Don't hold me to it - my synapses are a little fuzzy after nearly 30 years.

Yes Greg.... my synapses are probably even fuzzier but that was the name I am sure.

There was no possibility of getting good imaging of this moon during this event. First, it was unexpected and second the Pioneers used spin-scan for its camera..... there was a certain bit of rivalry between the science teams of Pioneer and Voyager, due to the simpler design of Pioneer and the heavy emphasis on particle and fields data from the Pioneers.

Pioneers were simpler spacecraft, but did a magnificent job by being first to directly probe the asteroid belt (no no knew back then whether the dust in the belts would be so dense as to damage spacecraft), first to direclty sense the radiation belts of Jupiter and Saturn, as well as determing whether the ring flyby at Saturn was safe for Voyagers (if one of these craft was go on to Uranus and Neptune). At one point in the Saturn flyby planning, one group was lobbying to send Pioneer 11 right thru the Cassini Division.

Fun thread.... brings back memories... once I get home I will check a recent book published about Pioneer...cannot remember the title right now, but I think participants of this thread will enjoy it.

PIONEER ROCK... I like that name.....

Craig