Bruce on flagship mission proposals

From Bruce Moomaw:

Not really all that much new in them, but there is some.

(1) Nothing at all on the release timing of the "New Frontiers 3" AO.

(2) The plan is still for NASA to pick its mission in February, while the ESA wouldn't decide whether to cooperate until the end of 2012 (and would in fact reduce its "L-Mission" choices from 3 to 2 in number only in late 2010). ESA's other two choices are still an ESA collaboration with NASA's "LISA" gravity-wave mission, or with Japan's "XEUS" X-ray astronomy mission. (This implies that there's some feedback between which OP Flagship mission NASA picks and whether it picks LISA, which is a very high-priority astrophysics mission for us.)

(3) Our Europa Orbiter could make Io flybys as low as 75 km to directly sample an eruption plume -- if it retains its onboard mass spectrometer, which is one of its lowest-priority instruments.

(4) The ESA really is apparently serious about a solar-powered Ganymede Orbiter to complement NASA's Europa Orbiter, and with a hefty 73-kg science payload (same presentation). It would spend 13 months making repeated Callisto flybys in 1:1 or 2:3 resonant orbits before turning its attention to Ganymede, where it would end up in a low circular orbit. I think that, once again, ESA's eyes are bigger than its wallet; but who knows?

(5) The ESA's Titan Lander would indeed be a lake floater, which would make a leisurely 6-hour atmospheric descent by parachute (to examine Titan's atmosphere in more detail), and then work for only 3 hours on the lake itself: (They're talking about putting a camera on it, which strikes me as an exercise in futility; but then the camera would only weigh 1 kg.)

(6) They're quite serious about dropping off the Balloon during the main spacecraft's first Titan flyby -- after its Saturn orbit insertion -- and then dropping off the Lake Lander on the next Titan flyby. Although the Balloon's projected lifetime wouldn't be nearly as long as the 2 years the main spacecraft would spend in Saturn orbit before inserting itself into orbit around Titan, the Balloon would have a small gimballed high-gain dish antenna on its gondola that could relay data back to the main craft at 2000 bps even at a distance of 5 million km -- that is, almost wherever the main craft happened to be in the Saturn system. During the Orbiter's close flybys of Titan, the Balloon could relay data at up to 1 million bps.

(7) The Balloon would indeed hang at 10 km altitude, making no attempt to approach the surface and pick up samples -- but ESA is talking about a possible auxiliary small flat "Geosaucer" that would be dropped from its gondola onto Titan's solid surface with a seismometer and magnetometer onboard.

(8) The Titan Orbiter would make a series of 7 Enceladus flybys during a period of a single month -- and, oddly, they are talking about subsurface radar sounding of the plume region, despite the problems that the Titan aerobraking would then cause the radar sounding antenna. I don't know whether this is a glitch in the presentation, but they mention it twice. Maybe the antenna would be retractable?

(9) The baseline plan is for the Titan Flagship to be attached to a SEP stage that would allow it to reach Saturn in 9 years -- without that, it would take 18 months longer to reach Saturn (and its time in orbit around Titan would be clipped from 20 months to 16 months).