The First Europa Lander, What can be done first, cheapest & best? Options

[ugordan]

There's more to radiation shielding than x-rays and gamma rays. In fact, I'd wager the primary damaging mechanism of Jupiter's radiation belts is directly via charged particles trapped in the belts (not secondary photons they produce when braking) and secondary particles. A low-Z material would be better suited for slowing down those suckers. In that vein it doesn't strike me as odd titanium would be used. In the end, it's always a tradeoff between different characteristics like primary absorption cross-section, secondary radiation production, etc.

[nprev]

Low-Z also means low weight. Ti's got a number of excellent, complementary properties.

[hendric]

I'll bet these guys have some good pointers on choosing radiation tolerant electronics

http://bura.brunel.ac.uk/bitstream/2438/14...rd06_hobson.pdf

[helvick]

Which is a very fair point - casual scanning of the usual sources didn't yield anything that indicated Titanium was often used for radiation shielding but that's not a surprise - most of the tech\materials stuff that crop up here tends to be in the "hard to find on google" category and I resisted the temptation to dig into the NTRS - anytime I do that months seem to disappear.

I was just looking at Doug's other point - the 1x1x0.8m safe masses 130kg - if that was _just_ titanium it would only be about 5.5mm thick plate. Making things out of solid metal, even a fairly low density one like Titanium, pushes total mass up awfully quickly.

[djellison]

http://opfm.jpl.nasa.gov/files/Y-McAlpine-...s%20Learned.pdf - big pdf containing a flash based presentation from http://opfm.jpl.nasa.gov/europajupitersyst...umentresources/ - they talk all about it.

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[helvick]

Ah no, I've been sucked in - see you guys sometime in February. At least I've found the high-Z vs low-Z discussion points and why high-Z has some particularly bad downsides for Juno which seems to explain the choice of Titanium rather than the Tungsten\Tungsten Copper that crops up in the bits I've found so far.

[Marz]

JEO (Jupiter Europa Orbiter) launch in 2020 land in 2026! let's light this candle!

"NASA is considering dropping two robotic landers on the surface of Jupiter's moon Europa..."
http://news.yahoo.com/jupiters-moon-europa...-212201869.html

[centsworth_II]

let's light this candle!

I take it this is a vote for an orbiter mission over a lander mission.

While the lander mission is exciting, the much longer lived and broader ( multiple moon flybys) orbiter mission is more interesting and will provide plenty of excitement in its own right.

[SFJCody]

Agreed that a broad reconnaissance would be preferable. But a short lived lander with a similar mission scope to MSL might well be able to find enough through detailed in-situ analysis as to make the case for a super-duper flagship very strong indeed, whereas an orbital only mission might merely find suggestive/ambiguous evidence.
Might being the operative word of course...

[Paolo]

the problem is: without an orbital reconnaissance you don't even know what are the most suitable sites where to land and make in situ analyses

[Drkskywxlt]

The bigger problem right now, Paolo, is there's no money for this unless a Europa lander can be proposed for a Discovery mission.