While it would be easy to blame
the events of September/11 on what's happening with plans for ambitious "space science"...but actually, plans to send humans to Mars,
even before September/11, were of extremely low priority inside NASA...
so nothing's really changed.

BUT!! If you divide future ambitious "space science" projects into ROBOTIC
or MANNED, the ROBOTIC missions planned
or underway are proceeding nicely.
EXAMPLES: [ESA] The Ulysses mission
has received another extension; the
Mercury Orbiter project is approved;
The Mars Express/Beagle-2 project
is now at the assembly & building. stage. And there's the European
Comet-Lander [what's its name?] that is
also in the R&D stage...and there's
even the modest SMART lunar-orbiter
now being assembled in Great Britain.

As far as ambitious unmanned NASA
projects?...
There's Mars Odyssey, already orbiting Mars; the successful NEAR
and DS1 missions; the future Mars Rover
missions; Cassini is nearing Saturn;
the Pluto flyby mission is finally approved; the CONTOUR comet flyby mission is in the R&D stage; STARDUST
is on its way to another comet; the NGST space-astronomy project is also
approved; and other missions too.

I haven't even mentioned Japan's
ambitious asteroid, lunar and martian
robotic missions...Nor have I mentioned
that India's and China's spaceprograms
BOTH have dedicated plans to sent unmanned spacecraft to the moon.

So it's more easy to be positive than negative about these "space science" projects now planned or underway, considering the political climate today.

Jacob