> Take for example asteroid mining, how long have we heard about that?
It's been a feature of science fiction since the early days. But making a serious effort at it depends on several things that are more recent:
* The discovery of 15,000 Near Earth asteroids, 90% of which have been found in the last 15 years : http://neo.jpl.nasa.gov/stats/ The Near Earth group are much easier to reach than the Main Belt asteroids. The more of them you find, the better the chance of some of them being the right composition and right orbit to mine.
* The development of higher power electric propulsion (ion and plasma) and high efficiency solar arrays, in order to power space tugs to bring back asteroid rock to a high Earth orbit. This has also happened over the last 15 years.
* Improvements in space robotics and high-bandwidth communications, which would allow real-time control of a processing plant in high orbit from the ground. This reduces the need for astronauts on site and lowers the cost.
* Growth of a market for the products of asteroid mining. There are now about 1400 active satellites in space : http://www.sia.org/wp-content/... (see page 8) and the number is growing. Without a way to refuel or repair them, they have to be replaced at great cost. Asteroid mining can supply fuel, both for the satellite itself, and to bring them to a repair station. That market is worth billions a year, but again, 15 years ago it was much smaller.
Not surprisingly, now that the pre-conditions exist, people are making serious efforts to develop asteroid mining.