NASA has approved two further robotic probes to the Outer
Planets. The first will be the Pluto New Horizons probe, to be launched in
January, 2006. If all goes well it will fly by Pluto, the only planet so far
never to have been explored by a robotic mission, around 2015, after a gravity
assist at Jupiter. The second is called Juno, which will launch by 2010 and
will enter a polar orbit around Jupiter five years later.
Further into the future, NASA hopes to build a launch the
Jupiter Icy Moons Orbiter (JIMO), a huge, nuclear powered space craft that is
envisioned to orbit and study several of the moons of Jupiter in turn. The mission
was at first designed to showcase NASA’s Prometheus nuclear power and
propulsion technology, but has been postponed indefinitely.
Will human beings ever venture to the Outer Planets, as once
imagined in the film, 2001: A Space Odyssey? Almost certainly they will,
eventually. But tremendous technological problems must be solved first. Even
with nuclear propulsion, trip times to the Outer Planets would be measured in
years. Either the lives and health of human explorers must be maintained over
that time, or new, faster propulsion techniques must be developed. And some
sort of active shielding against radiation must be built, perhaps an
electromagnetic field infused with plasma to simulate Earth’s magnetosphere. It
is certain, though, that given the human desire to see unknown places with
their own eyes, these challenges and other will, sooner or later, be overcome and
the great, human adventure in space that began over forty years ago will
continue to the edge of the Solar System.