[X] My Assistant

[Mark6]

Today I heard this on NPR: Exploring a moon by boat

The mission could launch around 2016 and be sailing on Titan around 2022 — if this team gets through a highly competitive selection process to get funding from NASA. Stofan and her colleagues are busy working up their proposal for when NASA begins to accept ideas for future Discovery-class missions.

Quick Google search on Dr. Stofan's name found this: What Next for Titan?

Ellen Stofan has a Discovery-class Titan lake lander proposal. I've not seen the presentation, but a friend who has tells me that it is less capable than the ESA lake lander proposed for TSSM. (This would make sense – ESA had a budget of ~$1B for just the lake lander and balloon. Stofan has just $450M and has to fit a carrier craft and launch vehicle into that budget.) The 2007 report did not look at lake landers. I know of Stofan by reputation, and she's highly competent. However, fitting in a carrier, lander (with entry shell), and launch vehicle within a Discovery mission budget seems ambitious. Perhaps this could be done with a New Frontiers budget ($650M with the launch vehicle provided by NASA outside this budget), although the 2007 budget suggested that a budget twice this amount would be needed just for an atmopheric probe.

Aside from above quote's understandable skepticism of the Discovery-class price tag, where would plutonium for this mission come from? I thought it is all already allocated?

[mcaplinger]

Aside from above quote's understandable skepticism of the Discovery-class price tag, where would plutonium for this mission come from?

From http://discoverynewfrontiers.nasa.gov/news...ews_051509.html

"Discovery Program investigations may propose the use of Advanced Stirling Radioisotope Generators (ASRGs) for missions enabled by radioisotope power systems. If selected for flight, NASA will provide up to two ASRGs, including the services associated with their provisioning on space missions, as GFE, and their costs will not be included in the cost cap."

ASRGs don't use as much Pu as thermocouple systems. NASA doesn't say where it's coming from, but presumably there is a source (I had thought that production was going to be resumed.)

As for skepticism about cost, IMHO the cost/risk pendulum has now swung to the extreme end of risk aversion and high cost, so anything that might help it swing back is a good thing.