JUICE, ESA's L-class mission to the Jovian system Options

[machi]

Yellow book is available (13.1.2012) - JUICE.

[tanjent]

Jupiter is the most distant target planet for which probes can manage on solar power without RTG's. So spacecraft going there need big panels, intricately folded prior to launch. Likewise I am guessing that the communications antennae need to be larger relative to the spacecraft itself than for probes heading to the inner planets and Mars. So the engineering challenges involved in powering and communicating with Jupiter-bound payloads are bound to be daunting.

[vjkane]

Jupiter is the most distant target planet for which probes can manage on solar power without RTG's. So spacecraft going there need big panels, intricately folded prior to launch. Likewise I am guessing that the communications antennae need to be larger relative to the spacecraft itself than for probes heading to the inner planets and Mars. So the engineering challenges involved in powering and communicating with Jupiter-bound payloads are bound to be daunting.

There have been several proposed solar powered Discovery and New Frontiers-class missions for the Saturnian system across 2-3 competitions. I've never heard that the reasons they weren't chosen was because of the proposed use of solar power. Two of the losing teams gave debriefs on the reviews of their proposals at an OPAG meeting, and solar power wasn't mentioned.

Given how small this community is, if solar power wasn't going to get past reviewers (and the reviews assess technical feasibility), I think that would be known by now in the community. The recent Decadal Survey Enceladus multiflyby concept used RTG, and they note was that RTGs were more mass efficient.

I don't think that we can say for certain about solar power at Saturn until a mission is selected, but there are good examples of professionals in the field believing they can will mission concepts using solar power.

BTW, NASA is offering up to two MMRTGs for the upcoming NF5 competition. Missions have been proposed to each of the candidate destinations using solar power. If the winning mission does use solar power, the fuel could be repackaged into a next get RTG and offered to a Uranus mission. (Repackage for more efficient and long lived thermocouples than MMRTGs.) This would give the mission about a third of what's been desired in most Uranus flagship orbiter concept designs, or about enough for a NF-class orbiter. The alternative, per the recent OPAG meeting is to miss the early 2030s window and wait until the mid or late 2030s and much long flight times.


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