In just the past year, NASA has put a probe into orbit around Vesta, launched probes to the Moon, Jupiter, and Mars, and continues to get amazing data from probes currently orbiting Mercury, Mars, and Saturn. Plus, the Kepler mission has found more than 1,500 potential exoplanet candidates, and the New Horizons probe is on target for a 2015 rendezvous with Pluto.
I personally think that in the next 20 years it will be commercial companies that push the boundaries of space exploration. NASA the ESA etc. will push the boundaries of academic research of course, but the money that commercialisation of space will bring will advance our understanding and exploration faster than it has done in the recent past. Especially since the moon landings and Voyager satellites.
I am not sure why private companies would push the envelope, where is the profit? What they generally do is take a proven technology and make it cheaper, *if* there is a way to monetise it (like launching satellites).
The profit is in more efficient ways to get satellites into orbit, the potential mining of meteors or god forbid planets, space tourism if it becomes financially feasible for the regular person.
Space has so many commercial opportunities which is why companies will push the envelope. Cheaper methods to get into space will also mean that more of NASA, ESA budget can go towards pure research. Just my pennies worth.
I never said that it was NASA is a phenomenal organisation which has advanced space explorations, science and engineering in a way no other could, it will continue for many years to come to have an important role to play. Just my personal opinion is that it should focus on more pure and applied science instead of getting satellites into space for companies and governments.
Of course they're no where near closed down they do some superb and cutting edge research.
If China were to try to claim the moon, you would see how quickly the US would catapult past them. Europe on Mars?, the US could be there tomorrow. All they need is an incentive. I would love to see another country attempt going there.