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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Member ![]() ![]() ![]() Group: Members Posts: 220 Joined: 13-October 05 Member No.: 528 ![]() |
It is tough to know just what 700 million Euros will buy on a mission like this. Several things about ESA make apple to apple comparisions with the US rather dicey. It was on this forum that I first heard that ESA planetary missions do not factor in the cost of instruments directly. If I'm understanding that correctly it means that the 700 million Euros goes for the launch vehicle, spacecraft, and possibly operation costs, but does not include the instruments. That has got to be giving you a healthy boost on effective budge (I'm thinking an insturment suite for this mission could run 50-100 million Eurios). Secondly, there is the European aversion to nuclear power on their spacecraft (largely a political hot potato, I think). I think most of the Billion Dollar Box studies that NASA did envisioned nuclear powered shipts. Not sure if solar power would be cheaper or not, but in any event the Europeans do not always think the same way that the JPL engineers do (for better or worse) and it's tough to be sure that the studies we did on outer planet orbiters would be directly applicable. When I read read the Laplace Report (a long time back, memory is vague) it struck me that they were coming up with missions very different from our concepts, and were estimating much smaller vehicles (launched on a Soyuz) and cheaper costs. It will be very interesting to see how these design studies turn out. |
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