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PIONEER chronology
Liss
post May 4 2009, 07:58 PM
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QUOTE (dmuller @ Apr 30 2009, 06:21 AM) *
After consulting JPL's NSSDC and Horizons websites, it seems that Saturn closest approach was at
01 Sep 1979 16:29:34 UTC at an altitude of 20,591 km (using a Saturn radius of 60,268 km).

Umm, in http://trs-new.jpl.nasa.gov/dspace/bitstre...5/1/03-0282.pdf actual TCA is given as 16:30:34.
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dmuller
post May 7 2009, 02:28 AM
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Pioneer 11 had a fairly close flyby of Atlas at 45,960km on 1 Sep 1979 15:06:32. To put it into perspective ... Cassini got closer to Atlas only once so far AFAIK!

QUOTE (Liss @ May 5 2009, 05:58 AM) *
Umm, in http://trs-new.jpl.nasa.gov/dspace/bitstre...5/1/03-0282.pdf actual TCA is given as 16:30:34.

I suspect that time is ET, which converts to 16:29:44 UTC. That's just 10 seconds off the times in Horizons. And at the time of C/A, the altitude doesnt change much so I'd take both times as being "equal enough" :-)


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Guest_PhilCo126_*
post Jun 17 2009, 03:38 PM
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Guests






We're ready for the upcoming 30th anniversary of the Pioneer 11 - Saturn flyby:

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dmuller
post Jun 17 2009, 11:18 PM
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Beautiful! And we're nearly there, 75 days and 57 million km to go ... historic realtime simulation (well, 30 years "late")


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Liss
post Jul 22 2009, 01:39 PM
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QUOTE (dmuller @ May 7 2009, 06:28 AM) *
QUOTE (Liss)

Umm, in http://trs-new.jpl.nasa.gov/dspace/bitstre...5/1/03-0282.pdf actual TCA is given as 16:30:34.

I suspect that time is ET, which converts to 16:29:44 UTC. That's just 10 seconds off the times in Horizons. And at the time of C/A, the altitude doesnt change much so I'd take both times as being "equal enough" :-)

The really strange thing is that NASA Release 79-108 issued August 22, 1979, lists all the events of Pioneer 11 Saturn encounter of September 1 against the TCA time of 18:00 UTC ERT = 16:34 UTC SCET, even if DSN Progress Report 42-53 lists the future TCA as 17:56 UTC ERT = 16:30 UTC SCET which fits nicely with post-flyby estimates. I cannot understand why NASA was off by four minutes just 10 days before the event.
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