[meteorite-list] All These Worlds Are Yours, Except Europa. Attempt No Landing There.

From: Sterling K. Webb <kelly_at_meteoritecentral.com>
Date: Mon Mar 21 13:24:56 2005
Message-ID: <4235EE2D.B0F268B7_at_bhil.com>

HI!

    I, for one, occasionally feel like we could do with a dose of monolith maker hijinks! Or any
evidence of others -- beyond a Martian bacterium.
    To quote another novel of wonder*, "The Universe is a pretty big place. So, if it's just us, it
seems like a terrible waste of space."

Sterling Webb

*Carl Sagan, CONTACT
-----------------------------------------------------

Darren Garrison wrote:

> The monolith makers aren't going to be happy with this:
>
> http://news.bbc.co.uk/2/low/science/nature/4347571.stm
>
> Monday, 14 March, 2005, 13:16 GMT
> Europe tells US: 'Come to Europa'
> By Jonathan Amos
> BBC News science reporter
>
> The next big cooperative European-US space mission will be to Europa, the ice-crusted moon of
> Jupiter.
>
> A joint working team is being set up to consider what sort of spacecraft would be needed and what
> each side could do.
>
> Officials in Washington and Paris are keen to follow up the spectacular success of Cassini-Huygens
> at Saturn.
>
> "It was a beautiful marriage and we really are looking to do a repeat," said Professor David
> Southwood, from the European Space Agency (Esa).
>
> Southwood told the BBC News website that "Europe could do Europa on its own", but that a cooperative
> venture was extremely attractive.
>
> "It's a natural for the next big international collaboration in space"
> Prof Fred Taylor, Oxford University
>
> Many scientists agree that Europa is now a high priority target for a major mission.
>
> The moon, discovered by Galileo, is slightly smaller than the Earth's Moon. Its covering of white
> and brownish-tinted ice is riven with cracks that are probably the result of stressing caused by the
> contorting tidal effects of Jupiter's strong gravity.
>
> Researchers speculate that tidal heating may even have produced vast oceans of water under the ice
> sheet and that this environment could harbour micro-organisms.
>
> Convenient time
>
> The Esa director of science held discussions about Europa with counterparts at the US space agency
> (Nasa) at the end of last week. "I've definitely piqued their interest," he said.
>
> The discussions are at a very early stage - and a mission that would launch no earlier than 2016 is
> some way off becoming a reality.
>
> Nevertheless, Professor Southwood said it was a good time to consider how the two agencies could
> build on their Saturn experience, which has produced stunning images of the ringed planet and put a
> lander on the surface of Titan.
>
> EUROPA - MOON OF JUPITER
>
> Orbit: 670,900km from Jupiter
> Diameter: 3,138km
> Discovered by Galileo and Marius in 1610
> Ice crust may be many tens of km deep
>
> The Americans had planned to go to Europa independently with their Jupiter Icy Moons Orbiter (Jimo).
> But the ambitious project, which would have used a nuclear propulsion system, has been shelved as
> Nasa re-focuses its budget on a White House initiative that could take humans back to the Moon.
> As a consequence, the European suggestion of a joint mission to Europa has been favourably
> entertained.
>
> As with Cassini-Huygens, Southwood envisages the new mission incorporating a double-spacecraft
> architecture.
>
> Surface imperative
>
> "You've got to have a relay satellite," he explained. "You go together; you fly out there in tandem.
>
> "They separate after Jupiter orbit insertion and then you leave the relay satellite in orbit around
> Jupiter, preferably in a resonance with Europa.
>
> "Then there's a debate about what you do at Europa. Personally, I would like deep-penetrating radar
> [on an orbiter]. But that's because I'm a remote-sensing man.
>
> "I believe you get more by getting the global picture than you do by scratching and sniffing the
> surface."
>
> But the pressure to go down to Europa's cracked and blotchy surface would be immense, said Professor
> John Zarnecki, the principal investigator on the surface science instruments loaded on to Huygens
> for its Titan descent.
>
> "If it is technically feasible to go to the surface, you would want to do that. Huygens' surface
> image on Titan says everything," the Open University researcher enthused.
>
> "But, it may be that what you want to do - to look below Europa's ice - you can do that better from
> orbit.
>
> "The Esa-Nasa group that's going to be set up will look at just these sorts of technical issues,"
> added Professor Zarnecki, who has been party to the initial trans-Atlantic discussions.
>
> Power needs
>
> Researchers at the German Aerospace Centre are already developing a prototype technology that could
> be used to melt through Europa's ice sheet. Any water might be a considerable (and possibly
> unreachable) way down - 20-30km down.
>
> Once under the sheet, the probe would take samples and drop mass to begin a slow climb back up the
> ice column. On the surface, it could then send data to an orbiter or relay satellite for onward
> transmission to Earth.
>
> DEVELOPING SPACE TECHNOLOGY
>
> Melting through Europa's ice
>
> Europe already has a major mission en route to Jupiter's orbit - the Rosetta mission, which will
> chase down a comet and put a lander on its surface. This has given Esa the confidence to go it alone
> to Europa if the Americans decide eventually not to participate in a joint mission.
>
> But a key factor is likely to be power systems. Although solar panels will work on spacecraft at
> that distance, the desire for sufficient energy to drive many instruments means any mission would
> really need to go with radioisotope thermal generators (RTGs) - solid state electrical generators
> powered by the heat of radioactive decay.
>
> Europe has no expertise with RTGs - the Americans have, and Cassini carries three to provide 700
> watts to its systems.
>
> "I'd much rather do this with RTGs," said Professor Southwood. "And that makes it almost certainly a
> joint venture with the Americans and why should we do it separately?
>
> "This was waiting to happen. Someone just had to say it."
>
> Professor Fred Taylor, of Oxford University, UK, said the case for going to Europa was compelling.
>
> "The attraction of Europa is that it is a water world - the surface is frozen, of course, because of
> its exposure to cold space, but not far underneath the ice is an ocean of warm water.
>
> "We have never explored such a place beyond our own Earth, and the technology required is not too
> different from the successful US-European Cassini-Huygens mission, so it's a natural for the next
> big international collaboration in space," commented the scientist, who worked on the 1990s Galileo
> mission to Jupiter.
>
> "It will be much cheaper than Jimo, which is more of a long-term project (and which has not been
> abandoned completely)."
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Received on Mon 14 Mar 2005 03:03:57 PM PST