OPAG Reports, Formal proposals/evaluations of future outer SS missions |
OPAG Reports, Formal proposals/evaluations of future outer SS missions |
Nov 9 2007, 08:28 PM
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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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Sep 2 2008, 04:04 PM
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Member Group: Members Posts: 706 Joined: 22-April 05 Member No.: 351 |
An August update on the two possible outer planet missions has been posted at: http://www.lpi.usra.edu/opag/flagshipOPF08.pdf
Both concepts are maturing and both look very feasible with compelling science. (I'm glad that I don't have to decide!) Report is only on the U.S. orbiter elements. Some highlights: Mission costs are being allowed to increase by a few hundred million dollars to enable more capable instrument packages. Selection between Jovian and Saturnian system destination is now Feb 2009. Risks for the Saturn mission are much lower (but appear to apply only to the orbiter element). Europa mission appears to have higher risk elements (assuming same scale used for both) because of the radiation environment. Current plan for the Titan in situ elements is to release them early in the Saturn Titan tour, which means a long period (12-18 months?) with only periodic relay by the orbiter and direct communication with Earth used in between. -------------------- |
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Sep 3 2008, 04:16 AM
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Senior Member Group: Members Posts: 1018 Joined: 29-November 05 From: Seattle, WA, USA Member No.: 590 |
Did you notice that Ares V was an allowed launch vehicle for this proposal? (It's on slide 26.) No one proposed anything using one, but it surprised me to see it as an option. Does that mean someone has an estimate for what that would cost?
--Greg |
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