Cato speculate?

> What will the impact of space development be on science and
> technology? Why? How?
Imagine first a radio telescope one kilometer in diameter: thrice the diameter of Arecibo and about ten times its sensitivity; it can lock onto a source 24/7 rather than a few minutes per day as Arecibo can, since Arecibo is fixed in a bowl-shaped depression in the ground. Then imagine a number of these, creating an array the size of the Moon's orbit around the Earth.
Expand this to dishes several km in diameter, in orbits out beyond Pluto, cooled down to liquid nitrogen temperatures by the sheer distance from the Sun, and forming an array the size of the solar system.
Then imagine how radio astronomy may benefit from such sensitivity and resolution.
Imagine optical telescopes built on the same principle. Such arrays are already in use on Earth. Imagine an array of mirrors with an effective aperture of hundreds of meters. We could see the sunspots on nearby stars, or map planetary surfaces and monitor weather systems on planets of nearby stars. This would still be difficult and expensive, of course: perhaps kilometer sized arrays of mirrors, the distance between them fixed and known to an accuracy of a fraction of the wavelength of the light being detected.
A single optical telescope on each side of the Sun, at Pluto's distance, would enable us to measure the parallaxes of nearby stars to thirty times the present accuracy, thus determining their distances from us to this accuracy, and stars thirty times as distant as presently may have their distances measured by parallax. Since parallax measurements are the first step in measuring the distance to *any* distant object, this increased accuracy would benefit distance measurements out to the quasars. Or two or three such telescopes could be sent out in interstellar space: each year would bring greater accuracy as they receded from each other.
The gravitational constant could be measured to a very great accuracy by letting two metal balls orbit each other. The product of the gravitational constant and the Earth's mass are known to nine or more digits, but the gravitational constant itself is known to much lesser accuracy. It would certainly be a natural high school science experiment, to verify the gravitational constant to within one or two significant figures.
Of course the above instruments, particularly the optical telescopes, could be launched from the Earth without any industrial infrastructure in space. But it would be much cheaper to do so from space.
Space colonies could be sent into orbit around the various planets, to serve as bases from which to observe the planetary surfaces and send probes down, returning material for analysis at the base. Later, such bases would be excellent for manned landings.