PIONEER chronology |
PIONEER chronology |
Guest_PhilCo126_* |
Jan 4 2008, 05:35 PM
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Guests |
Just thought I would start a similar topic as the 'VOYAGER chronology' ... of course with nice diagrams
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Apr 21 2008, 10:56 PM
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Member Group: Members Posts: 813 Joined: 29-December 05 From: NE Oh, USA Member No.: 627 |
Interesting to note that CASSINI XXM end trajectory will be quite similar to the INSIDE ring passage
rejected for PIONEER 11 at Saturn... 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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