Big storm on Saturn Options

[john_s]

The solar system is a happening place this week! I just learned of a major storm in Saturn's northern hemisphere, being monitored by the usual band of talented amateurs. See this site for a list of recent images. Chris Go's site has a particularly nice image.

John

[stevesliva]

I hate to ask this question, but I'm really curious. If Cassini had a scan platform, would on-demand retargeting be a lot more feasible? I'm thinking, yes, we'd simply be trading off imaging vs. imaging, not imaging vs. the whole suite. But I don't know enough about the sequencing. Would a spacecraft with a scan platform have a separate sequence for the scan platform that could be modified by itself?

[john_s]

I hate to ask this question, but I'm really curious. If Cassini had a scan platform, would on-demand retargeting be a lot more feasible?

It would certainly be simpler, but nothing in spacecraft operations is simple. There would still be numerous issues to be resolved- what pre-planned observations would be displaced, where would the data be put and when would they be downloaded, thermal implications of the new scan platform orientation would have to be checked, and new command sequences would have to be developed and tested. The Mars Rovers are always responding to new information on ~24 hour timescales, but they and their operations are designed from the ground up to be able to do that. Orbital missions are never that flexible.

John

[FatSplenda]

It would certainly be simpler, but nothing in spacecraft operations is simple. There would still be numerous issues to be resolved- what pre-planned observations would be displaced, where would the data be put and when would they be downloaded, thermal implications of the new scan platform orientation would have to be checked, and new command sequences would have to be developed and tested. The Mars Rovers are always responding to new information on ~24 hour timescales, but they and their operations are designed from the ground up to be able to do that. Orbital missions are never that flexible.

John

Ah! Finally, someone gets it.
I am part of the tactical uplink operations and engineering team for the Rovers, and I'm glad to see that it's understood how different these things can be!
Based on the little I know about Cassini (I've never been acquainted with its sequencing process either, other than its pointing design and control suite for attitude constraints), I would guess that having a scan platform has just as many pros as cons. The pros would obviously include increased science -- you no longer have to move the whole spacecraft -- and maybe reduced usage of the reaction wheels. Would be tough to say without a high-fidelity analysis there. The cons would be adding more analyses and sequence flight rule checks for the operations team, and wear and tear for the engineering team.
No such thing as a free lunch.
In any case... pretty pics!