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PIONEER chronology
tedstryk
post Apr 19 2008, 07:19 PM
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QUOTE (PhilCo126 @ Apr 19 2008, 04:59 PM) *
( Saturn's rings appear much narrower in 2008 & 2009 )

No, it is exactly the same pass as the 1979-80 crossing.


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belleraphon1
post Apr 21 2008, 10:56 PM
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Interesting to note that CASSINI XXM end trajectory will be quite similar to the INSIDE ring passage
rejected for PIONEER 11 at Saturn... smile.gif

http://planetary.org/blog/article/00001392/


The Perils of PIONEER 11
http://www.geocities.com/CapeCanaveral/Lau.../2099/9711.html

"The more daring trajectory would take Pioneer inside the rings, with closest approach about halfway between the cloud tops and the innermost edge of the main rings. This was a relatively dangerous area, because there was known to be at least one faint ring inside the main ones. The estimated probability of spacecraft survival ranged from over 99% to under 1%, depending on whose ring-density model you believed. The payoff was a unique opportunity to observe Saturn and its magnetosphere up close, using an old spacecraft whose useful life was nearly over anyway. However, actually losing the spacecraft at the ring-plane crossing would considerably reduce the data return. After a long debate, the principal investigators who ran Pioneer's instruments voted 11 to 1 in favor of this "inside" mission.

The more conservative "outside" plan specified two ring-plane crossings, both well outside the visible rings. The chosen distances for the crossings matched the flyby distance needed for Voyager 2 if it were to reach Uranus. The Voyager planners, given a unique and irreplaceable opportunity to visit two more planets, badly wanted to know if that distance presented any risks to their spacecraft. Such a flyby was also much safer for Pioneer, assuring Saturn data return after ring-plane crossing and also providing for a continued mission on into deep space. The final decision was made at NASA Headquarters: Using Pioneer as a pathfinder for the Voyager Uranus-Neptune mission was more important than getting maximum return from the Pioneer flyby alone. Pioneer would take the relatively safe "outside" trajectory. "

In 1979, my son David turned two...... my daughter was a plan in waiting....

Craig
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dmuller
post Apr 21 2008, 11:47 PM
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QUOTE (belleraphon1 @ Apr 22 2008, 08:56 AM) *
Pioneer would take the relatively safe "outside" trajectory. "


Only to nearly crash into a then-unknown but photographed moon, possibly being Janus or Epimetheus


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tedstryk
post Apr 22 2008, 08:44 PM
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QUOTE (dmuller @ Apr 22 2008, 12:47 AM) *
Only to nearly crash into a then-unknown but photographed moon, possibly being Janus or Epimetheus


Well, ~2500 km isn't exactly the near miss it is often made out to be, but it still led to some nail-biting.


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dmuller
post Apr 23 2008, 07:00 AM
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QUOTE (tedstryk @ Apr 23 2008, 06:44 AM) *
Well, ~2500 km isn't exactly the near miss it is often made out to be, but it still led to some nail-biting.

Any good reference on the latest analysis of that "encounter"? It would make a good line on my website. Just by looking at it, it remained the closest flyby of an outer-planet moon until Galileo's Io swing-by during its Jupiter orbit insertion.


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ustrax
post Apr 24 2008, 03:54 PM
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QUOTE (nprev @ Apr 19 2008, 02:00 AM) *
What a year 1979 was...


At least it gave the title to one of my 10 favourite musics ever... rolleyes.gif
...And I was about to go to school...those were the days... smile.gif


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tedstryk
post Apr 24 2008, 04:08 PM
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QUOTE (ustrax @ Apr 24 2008, 03:54 PM) *
At least it gave the title to one of my 10 favourite musics ever... rolleyes.gif
...And I was about to go to school...those were the days... smile.gif


I love that song.


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ustrax
post Apr 24 2008, 04:25 PM
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That's my Ted "Smashing" Stryk! cool.gif
I sure need an extra top 10 only for them...


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nprev
post Apr 24 2008, 11:57 PM
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<dancing in my seat>...yeah, I love that song, too! smile.gif


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A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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Guest_PhilCo126_*
post Dec 7 2008, 10:03 AM
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With the passed 35th anniversary of Pioneer 10 Jupiter flyby ( 03 Dec 1973 ) it's time to look forward to the 30th anniversary of the Pioneer 11 Saturn flyby ( 01 Sep 1979 ) as illustrated here:





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Guest_Enceladus75_*
post Dec 8 2008, 04:09 AM
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If I remember from reading an article years ago there was a proposal to fly Pioneer 11 through the Cassini Division of Saturn's rings as it was thought to be clear. Lucky they didn't because of course the Voyagers later found that it was by no means a clear division. blink.gif

The historic Pioneer 10 flyby of Jupiter took place just over a year before I was born (and Pioneer 11 the month before) and for some reason in my mind the band Wings's song "Jet" seems to be a very appropriate number for the Pioneer 10 encounter.... cool.gif

Jet By Wings (1973)

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4th rock from th...
post Dec 8 2008, 06:30 PM
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Here are two P10 images (A5 and A7) that I tried to correct for the planet's rotation and spacecraft motion. Still very rough, but I think that the relative positions of the cloud features are closer to reality, although there are still some scale issues.

Attached Image

Attached Image


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Liss
post Mar 1 2009, 10:15 AM
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Well, a side question to Pioneer chronology...

In SP-446, Pioneer -- First to Jupiter, Saturn and Beyond, at p.79 one reads:

On November 7, Pioneer crossed the orbit of Sinope, the outermost satellite of Jupiter. In the following few days, the
spacecraft successively crossed the orbits of Pan (renamed Carame) and Andrastea (renamed Ananke). By November 21,
Pioneer 11 had crossed the orbit of Hera (renamed Elara) at just over 11.75 million kilometers (7 million miles) from Jupiter;
it later crossed the orbits of Demeter (renamed Lysithea) and Hestia (renamed Himalia).


So what are those forgotten names for the satellites of Jupiter, what is the history behind? And what is "Pan (renamed Carame)" in the context of the 1974 flyby of Jupiter?

And another quote from 1973:

Early in the encounter, Pioneer crossed the orbit of Hades, first of Jupiter's four outer moons; the following day, it crossed the orbit of Pan.
On November 11, it crossed Amdrastea's orbit. On November 22, eleven days later, Pioneer will reach and cross the orbits of the three middle moons, Demeter, Hera, and Hestia, located 11.3 million kilometers from Jupiter.
On December 3, the day of encounter, the spacecraft will make its closest approach to all five of Jupiter's inner moons.


Which one of the outer satellites is not mentioned?
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Guest_PhilCo126_*
post Mar 1 2009, 06:34 PM
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Check: http://en.wikipedia.org/wiki/Moons_of_Jupiter
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Liss
post Mar 3 2009, 08:12 PM
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QUOTE (PhilCo126 @ Mar 1 2009, 09:34 PM) *

No, PhilCo126. This reference does not contain the names in question.
Of course, it's not a problem to find that names Hestia, Hera, Demeter, Andrastea, Pan, Poseidon, and Hades were given to the seven Jupiter moons, J VI through J XII, in 1955 and replaced in 1975 by the names we are used to see. I was asking about the story behind this short-lived nomenclature that was in official use during the Pioneer flybys.
By the way, here in Russia I never heard of those old names earlier. Not because I was young in 1975 -- I've read a lot of books in astronomy which could contain them.
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