Where to search for life on Europa

Much of Europa's surface is relatively unscarred by craters. Some think
volcanic activity resurfaces the moon.

With Europan volcanoes, the "lava" would be liquid water from beneath
the moon's surface. The "basalt" would be frozen water ice, like the
stuff we find mammoths in.

IMO, we don't need to drill through Europa's icey crust to search for
life. Surface ice in regions of recent volcanic activity would be a good
place to look.

--
Hop David
http://clowder.net/hop/index.html

I think we should drop a rover in one of those deep cracks. It's a
likely place to find relatively fresh material from below the ice.
It would be a waste of resources to not include at least a lander if
not a rover on JIMO. I think it should have several in fact.


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In article ,
Buck Galaxy wrote:
It would be a waste of resources to not include at least a lander if
not a rover on JIMO. I think it should have several in fact.

Trouble is, landing on Europa is *hard*. It's a big moon with no
significant atmosphere, so you'll need a lot of rocket braking for a soft
landing. All the more so if you come in at greater than Europa escape
velocity. (If memory serves, none of the Europa-mission concepts, not
even JIMO, envisions actually orbiting Europa -- rather, the intent is to
orbit Jupiter and make repeated Europa encounters.)

That means that a lander is not a compact little spacecraft, but a compact
little spacecraft on top of a big multistage rocket. This is not a minor
add-on to an orbiter mission.

Survival on the surface is also a bit problematic, since it's a high-
radiation environment. (Orbiters can mitigate this by using elliptical
orbits and spending most of their time at higher altitude.)
--
"Think outside the box -- the box isn't our friend." | Henry Spencer
-- George Herbert |

Henry Spencer wrote:
Trouble is, landing on Europa is *hard*. It's a big moon with no
significant atmosphere, so you'll need a lot of rocket braking for a soft
landing. All the more so if you come in at greater than Europa escape
velocity. (If memory serves, none of the Europa-mission concepts, not
even JIMO, envisions actually orbiting Europa -- rather, the intent is to
orbit Jupiter and make repeated Europa encounters.)

Nope. The intention is "[l]ow altitude, high inclination
orbits of all three icy moons." JIMO will brake into a
very high orbit of one of the moons, slowly spiral down,
then spiral back up and move along. I'm pretty sure the
final state will be a low orbit around Europa. Seeing as
how Europa is the cornerstone of the mission it wouldn't
make a whole lot of sense to get the least science there.

It's right on the main JIMO website in the short list of
"key capabities of the mission":
http://ossim.hq.nasa.gov/jimo/

Additionally, the JIMO SDT report* includes a
recommendation for a "Europa surface science package".
Which, this early in the design phase, could potentially
be anything from a drop zond to a surface station to an
ice melter with a DSRV.

(*) http://ossim.hq.nasa.gov/jimo/JIMO_SDT_REPORT.pdf

(Henry Spencer) wrote in message ...
(If memory serves, none of the Europa-mission concepts, not
even JIMO, envisions actually orbiting Europa -- rather, the intent is to
orbit Jupiter and make repeated Europa encounters.)

That would put the lie to the name of the mission, don't you think?
It's to be called the Jupiter Icy Moons Orbiter!

--
Rainforest laid low.
"Wake up and smell the ozone,"
Says man with chainsaw.
John J. Ladasky Jr., Ph.D.

Henry Spencer wrote:

...(If memory serves, none of the Europa-mission concepts, not
even JIMO, envisions actually orbiting Europa -- rather, the intent is to
orbit Jupiter and make repeated Europa encounters.)

As others have pointed out, JIMO proposes to orbit Europa, as well as
Ganymede and Callisto. Indeed, even the now-defunct original Europa
Orbiter mission concept proposed to insert into europan orbit. Looks
like you'll be handing out an ICH T-shirt to Christopher ;-)

--


Alex R. Blackwell
University of Hawaii

On 2004-07-07, Alex R. Blackwell wrote:
Henry Spencer wrote:

...(If memory serves, none of the Europa-mission concepts, not
even JIMO, envisions actually orbiting Europa -- rather, the intent is to
orbit Jupiter and make repeated Europa encounters.)

As others have pointed out, JIMO proposes to orbit Europa, as well as
Ganymede and Callisto. Indeed, even the now-defunct original Europa
Orbiter mission concept proposed to insert into europan orbit.

I'd love to see the pitch for the mission if they didn't.
Attention-grabbing, sure, but it'd be a little misleading otherwise...

--
-Andrew Gray

Alex R. Blackwell wrote:
Henry Spencer wrote:

...(If memory serves, none of the Europa-mission concepts, not
even JIMO, envisions actually orbiting Europa -- rather, the intent is to
orbit Jupiter and make repeated Europa encounters.)


As others have pointed out, JIMO proposes to orbit Europa, as well as
Ganymede and Callisto. Indeed, even the now-defunct original Europa
Orbiter mission concept proposed to insert into europan orbit. Looks
like you'll be handing out an ICH T-shirt to Christopher ;-)

Nah, he hedged before hand so it doesn't count.

"Christopher M. Jones" wrote in message ...
Henry Spencer wrote:
Trouble is, landing on Europa is *hard*. It's a big moon with no
significant atmosphere, so you'll need a lot of rocket braking for a soft
landing. All the more so if you come in at greater than Europa escape
velocity. (If memory serves, none of the Europa-mission concepts, not
even JIMO, envisions actually orbiting Europa -- rather, the intent is to
orbit Jupiter and make repeated Europa encounters.)

Nope. The intention is "[l]ow altitude, high inclination
orbits of all three icy moons." JIMO will brake into a
very high orbit of one of the moons, slowly spiral down,
then spiral back up and move along. I'm pretty sure the
final state will be a low orbit around Europa. Seeing as
how Europa is the cornerstone of the mission it wouldn't
make a whole lot of sense to get the least science there.

It's right on the main JIMO website in the short list of
"key capabities of the mission":
http://ossim.hq.nasa.gov/jimo/

Additionally, the JIMO SDT report* includes a
recommendation for a "Europa surface science package".
Which, this early in the design phase, could potentially
be anything from a drop zond to a surface station to an
ice melter with a DSRV.

(*) http://ossim.hq.nasa.gov/jimo/JIMO_SDT_REPORT.pdf

I wonder whether three almost identical vehicles would be cheaper,
possibly using one to relay information to the others.

Alex Terrell wrote:
I wonder whether three almost identical vehicles would be cheaper,
possibly using one to relay information to the others.

Unlikely. The enabling technology for a Jovian Moon
orbiter mission is nuclear electric propulsion.
The Isps involved are sufficiently high so that in this
delta V range the mass ratio scales pretty close to
linearly with regard to delta V increases. More
importantly, if you max out the achievable mass ratio
(within reason) on a NEP mission you end up with a hell
of a lot more delta V capability than is needed for
orbiting a single Galilean moon.

Potentially, an all-chemical propulsion set of
missions could be cheaper with more spacecraft,
depending on the details. With NEP the added cost
of bigger tanks with more propellant is likely to
be small compared to the cost of duplicate
spacecraft and propulsion systems.