Mike, first of all, sorry, I accidentally hit delete instead of reply. Second, I thought it was push broom. At any rate, I could imagine it be slightly useful if it was for albedo studies of Io's polar regions (in other words, areas where Juno would have a unique angle and on Io, where things rapidly change), but it would otherwise be useless.

An article from Spaceflightnow: http://www.spaceflightnow.com/news/n0909/24juno/
I didn't realize that the launching date of MSL (Curiosity) could be affected by a late Juno launched (in her window).

It will be interesting to see the impact this has on the trajectory. I am sure Jason will be examining it to see if it creates any Io opportunities.

They haven't released a new reference trajectory, but I would imagine that even with a change in the arrival geometry, they aren't changing their science orbit very much, so it wouldn't setup opportunities that are too terribly different from what we see now.

No, but I was hoping that it might (by luck) make some of the better opportunities come sooner, while JunoCam is more likely to be operational.

Here's a question: does earlier departure really equate to earlier arrival? With both Voyager and (I thought) New Horizons, the later departure had the earlier arrival.

--Greg

They're not necessarily related. It depends on Jupiter injection velocity. VGR 1 and 2 had different trajectory requirements and different departure speeds. It's not impossible to time the arrival on the same date, but that wouldn't necessarily be a trajectory with lowest TCM delta-V requirements along the way.

I think that maintaining the science orbit will be a requirement.

The issue is whether the specific timing allows any providentially close approaches to the moons, but that probably won't be determinable until after launch.

I was thinking about the extra large and sensitive solar arrays they are using - I assume the intent is to point these at the Sun, however would they get improved results by pointing them at the largest nearest emitter of indirect light, ie Jupiter itself?

Does Jupiter "collect" and radiate back in a way that would be advantategous?

Think of it this way; suppose Jupiter were a perfect, flat mirror. Then it would be equally good to orient the panels towards the Sun's image in that mirror. Make it a sphere -- still perfectly reflective -- and then the image is much worse than the real Sun, since it scatters the light. Now look at the real Jupiter, which reemits lots of the light at infrared frequencies that the solar panels can't use.

I'd be surprised if Juno could get even 1% as much energy from Jupiter as from the Sun, even at closest approach.

--Greg

I see that the end-of-mission plans for Juno call for a crash into Jupiter for planetary protection purposes. Am I the only one who thinks that sounds kind of unnecessary? We're flying this probe into a deep space high radiation environment. Is there really any possibility that Earth bugs could survive that radiation? And the probe is being parked in a polar orbit without close satellite flybys. Is there really any possibility that it would crash into (say) Europa in any not-extremely-distant future? And if it is only the really distant future, then magnify the point about earth bugs getting thoroughly sterilized by the high radiation. I don't see the harm in flying it as long as possible to squeeze all the science we can out of it. Or is there some good science to be done on a Jupiter dive?

Yes, and yes.

It's just not a risk worth taking, Europa is too important.

Does anyone have a copy of the paper "Planetary Protection Trajectory Analysis for the Juno
Mission" whose abstract is at http://pdf.aiaa.org/preview/CDReadyMAST08_...PV2008_7368.pdf ?
I'm curious now how the probabilities really work out for impact on a moon.

I suspect that the mission will be extended as long as the spacecraft systems can support the final disposal of the spacecraft, much like Galileo was. But the dose rates are pretty high, so Juno likely won't last a lot longer than its primary mission anyway.