OPAG Reports, Formal proposals/evaluations of future outer SS missions |
OPAG Reports, Formal proposals/evaluations of future outer SS missions |
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![]() Senior Member ![]() ![]() ![]() ![]() Group: Members Posts: 2530 Joined: 20-April 05 Member No.: 321 ![]() |
http://www.lpi.usra.edu/opag/announcements.html
That's one little URL with a lifetime's worth of reading material. Three detailed studies are available in PDF format. The missing body is Titan, which will be the subject of a forthcoming report. The three focus missions are: Europa Explorer: Fairly detailed description of a mission that is pretty much what Europa Orbiter would have been. Jupiter System Observer: Basically, Galileo 2 (without the antenna mishap!). The craft would start with a 3-year tour of all the Galileans, then spend 1 year in an elliptical Ganymede orbit, then the rest of the mission in a tight, polar Ganymede orbit (like MGS at Mars). That would map the heck out of Ganymede, but also be close enough to the rest of the system to make long-range observations for years. Note that Ganymede would thereby provide a lot of radiation shielding. Enceladus: where three profiles are examined in depth: Enceladus Orbiter only; Enceladus Orbiter with soft lander; Saturn orbiter with Enceladus soft lander. There's more to chew on here than I have had (or may ever have) time for, but I'll throw in my two cents' worth: Seems like a Europa-only mission would only benefit from coming after a JSO. EE would explore Europa much better than JSO would; why even have JSO observations at Europa if EE came first? In many ways, these two missions are competitive. EE would have the big payoff, but JSO seems like basic recon that would prime EE, especially giving specs on radar performance. But if we waited til JSO was 4 years into its mission before completing design of EE, then put EE sometime mid-century. If an Enceladus mission included a Saturn orbiter, then maybe the same orbiter could provide data relay for separate Titan elements. However, a lot of the Enceladus science goals would require an Enceladus orbiter, so I don't think a Saturn orbiter for Enceladus/Titan will win out. Note that Enceladus orbital velocity is low enough that the craft could manage to take lots of hits from ice pellets and survive. Put a bulletproof vest on the craft and let it soar through the plumes endlessly. |
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Junior Member ![]() ![]() Group: Members Posts: 26 Joined: 13-August 05 Member No.: 464 ![]() |
The reports are both very exciting, from what I've been able to get through so far. I've read the rationale as to why there is no landed element with the JEO, and it is very logical, sensible, and well-argued. But nevertheless, in an irrational way, I do wish there had been some way of attempting it this time; the 300-350kg soft landers studied, admittedly only in a preliminary way, for the ESSP and Icy Moons Lander were exciting (more so than the JGO element, though I know it will do great science - hard to squeeze in to a 300kg lander). And my impression was that Huygens didn't have the benefit of a well understood surface during its design - though then again, it did have a very helpful atmosphere, and landing wasn't the primary goal from memory. Very pleased to see that deletion of the NAC is such a long way down the descope list, given that the absence of metre-scale imaging seems to be one of the reasons why a lander is out of the question for now.
Discussion of the choice of MMRTG c.f. ASRG was also intriguing, and one of the areas where I thought the JEO was really advancing its case as the safer choice. Equally, its readiness to launch at the earlier October 2018 opportunity was put forward with some confidence. Very much looking forward to hearing the results, I'd love Europa to get up this time, but Titan would hardly be a disappointment, Roly |
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