[X] My Assistant

[Guest_PhilCo126_*]

Just thought I would start a similar topic as the 'VOYAGER chronology' ... of course with nice diagrams

[belleraphon1]

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

[dmuller]

Pioneer would take the relatively safe "outside" trajectory. "

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

[tedstryk]

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.

[dmuller]

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.