Enceladus-3 (March 12, 2008) Options

[Guest_AlexBlackwell_*]

Excerpt from Cassini Significant Events for 02/16/06 - 02/22/06:

"As mentioned in previous weeks, the project has been working on adopting a new reference trajectory in order to raise the minimum Titan flyby altitude for various encounters. Today the project reached a decision to proceed with the 'optocc2' trajectory. Additional work is still to be performed before delivery of the final files. This will include minor tweaks that have been analyzed in other trajectories, adjusting orbit 68 timing, and capture of an Enceladus plume occultation on orbit 28."

For the record, the new reference trajectory will result in an even more spectacular Enceladus-3 flyby [61EN (t) E3] on March 12, 2008.

[Guest_BruceMoomaw_*]

TWENTY-FIVE KM?!! You guys are really taking this place seriously, aren't you? I hope the navigation is better than that on MCO...

In that connection, one catastrophe that has yet to strike the US space program is the failure of an long, expensive outer Solar System mission just before its arrival. What will the public and Congressional reaction be when that finally happens? It looked as though it might happen with Galileo, but JPL succeeded (to their unquestionable credit) in pulling enough chestnuts out of the fire to remove that impression in that case.

At the risk of setting off the dog (aka Alex) again: I mentioned this point to Spilker's subgroup on Europa lander design at the Europa Focus Group Workshop, and got an enthusiastic response from JPL's Karla Clark -- we do NOT want something as expensive and long-term as a Europa Astrobiology Lander to fail at the very moment it's trying to land on Europa, and for that reason the best role for a little piggyback lander attached to Europa Orbiter may well be to check out the engineering characteristics of Europa's surface rather than carrying out any specifically scientific studies.

[Guest_AlexBlackwell_*]

...JPL's Karla Clark -- we do NOT want something as expensive and long-term as a Europa Astrobiology Lander to fail at the very moment it's trying to land on Europa...

Now that's a visionary statement.

I'm wondering about this figure as well, I noticed volcanopele edited it out of his post. Does that figure really hold in the new updated trajectory?

"Officially," the new reference trajectory is still in review at the Project/Program level; a decision should be forthcoming very shortly. I won't speak for Jason, but unofficially, the 25 km figure is the new Enceladus-3 flyby C/A altitude under all options that were being considered.

What exactly is the scientific justification of such a dangerously close pass?

More on that later; however, sooner than 2008

[volcanopele]

Technically, that number is official (well, it isn't going to change). As the Sig. events report suggest, a few additional tweaks are planned, but nothing that will effect Enceladus-3.

[Guest_AlexBlackwell_*]

Technically, that number is official (well, it isn't going to change).

I meant officially released. As you note, though, it's not going to change, especially since that C/A altitude was the same under all options. And I am heartened that the new reference trajectory helps out RSS, too