Cato speculate?

Jack,

The question while a good starter is a bit too broad.
Any undertaking in large scale development will create
advances in science and technology. Whether it is in
putting up space habitats or underwater cities or a
global effort to cure cancer.

That being said, I believe it is best to look at this
question in terms of what advances that space
development can give us, that cannot be achieved
otherwise.

Jay has already picked out a few areas that I would
like to regroup to put some order to the list:

1) Development that monitor the Earth for scientific
purposes (weather, NASA's earth obs program,)

2) Development that provides new commercial services
to the Earth (remote sensing, commsats, sat tv/radio,
gps, manufacturing techniques)

3) Development leading to technologies for furthering
space exploration (propulsion, remote sensing
instruments, communication subsystems, power supplies,
etc)

4) Science goals obtainable from space (being able to
view high energy wavelengths, NASA's origin program,
astrobiology, search for life/intelligence, planetary
geology)

5) Military developments (important group if trying
to get whole picture, this includes warning system for
asteroid impacts, missile defense, remote sensing,
communication eavesdropping, radar)

These five categories can further be explored on an
individual basis for a more exhaustive listing, but it
does give a focus for discussing such a broad topic.

As Arthur has suggested, the most amazing developments
are often serendipous discoveries. One of my favorite
examples is to look at radio astronomy for a good
example as a serendipous discovery spawning a
scientific revolution. When Carl Jansky first
discovered radio waves interfering with his work at
Bell Labs in the 1930s, most scientists ignored him.
However, thanks to all the left over radio equipment
after WWII, radio astronomy was able to take off and
go on to discover quasars and pulsars and identify
many interstellar gases! (not to mention spawning
SETI)

Ryan