The HST's space mission will end in a decade or so, but NASA has not been idle. The ultimate goal of the NGST is to gain an understanding of how our universe evolved after the Big Bang. Because the light that comes to us from the very distant first stars and galaxies in the universe has a frequency lower than the frequency range of visible light, their study requires observations to be made in the infrared portion of the spectrum. The NGST is designed to have these capabilities, unlike the HST, which operates from the ultraviolet to the near infrared. But you don't have to be part of a NASA mission to study the stars.
Astronomy is one area of science where amateurs regularly contribute to the body of knowledge.
Amateur astronomers all over the world have their telescopes poised to discover new comets and to patrol distant galaxies for supernovas. They then send the data to professional astronomers, who use the information in their research. Another astronomical activity that is gaining popularity is watching the sky for space objects such as comets and asteroids. If you simply want to use a telescope to enjoy the beauty and mystery of the heavens, you can view the four largest moons of Jupiter and the rings of Saturn through most commercially available telescopes. With respect to constellations, the seasonal skies provide a changing light show.