The Hubble Telescope's wide-field planetary camera took this image in 2007 of the "last hurrah" of a star like our sun. The white dwarf is ending its life by casting off its outer layers of gas, which form a cocoon around the star's remaining core. Blue corresponds to helium, blue-green to oxygen, and red to nitrogen and hydrogen. Ultraviolet light makes the material glow. *
Image: NASA, ESA, and K. Noll (STScI) * View Slideshow 
1990: The Hubble Space Telescope is launched, beginning a new era of deep space observation that opens up the universe to prying eyes as never before.
NASA's telescope, named for American astronomer Edwin Hubble, was placed into Earth orbit by the space shuttle Discovery. Despite some early teething problems and more recent, well-publicized maintenance issues, Hubble remains a crown jewel in NASA's tiara.
Hubble was not the first space telescope but it is by far the most sophisticated, providing earthlings with unprecedented detail and spectacular views of their universe. The images sent back by Hubble have not only advanced the cause of space research, their haunting, spectacular beauty has boosted the popularity of astronomy in general.
The idea for a space-based observatory goes back at least to the 1920s, when German rocket scientist Hermann Oberth discussed the possibility in The Rocket Into Planetary Space.
In 1946, astrophysicist Lyman Spitzer spelled out the advantages such an observatory had over its earthbound counterparts: Being free of atmospheric interference, a space telescope is able to bring distant objects such as stars into much sharper focus. Additionally, the absence of an atmosphere makes it possible for a telescope to observe unrestricted infrared and ultraviolet light.
Spitzer, a passionate advocate of the orbiting space telescope (so much so that he is referred to as its father), eventually headed a committee that laid out the objectives for what would become the Hubble Space Telescope.
During the 1960s, a number of smaller telescopes found their way into orbit, with NASA’s Orbiting Astronomical Observatory 2 perhaps the most successful.
Despite enthusiasm in the scientific fraternity for a more powerful Large Space Telescope, or LST, the politicians who would provide the funding were not so easily impressed. In 1974 the project was scrapped altogether as part of deep congressional budget cuts. When it was revived and green-lighted four years later, the project was given a budget of $36 million, half the original request.
Consequently, Hubble was built to more modest specifications than originally envisioned. Nevertheless, innovative design features (the ability to be serviced and upgraded by astronauts being a big one) represented a quantum leap in space telescopes.
The road to success had a few potholes, though. Hubble’s early years were plagued by production delays and cost overruns. After the telescope became operational, it was discovered that the main mirror had been made to the wrong specs, causing a blurring of images. That resulted in the first of several shuttle visits to the orbiting telescope by a maintenance-and-repair crew.
The mirror problem resolved, Hubble finally began earning its keep. The story since then has been a nearly unbroken string of successes.
Among them, Hubble has provided the deepest view of the universe yet, allowing astronomers to measure its precise age. It has also confirmed the existence of dark energy. And then there are all those pretty pictures, of course.
Hubble's recent troubles owe more to the vagaries of the space shuttle program than to any organic problem. After several delays, the telescope will finally receive some long-overdue maintenance when Servicing Mission 4 arrives next month.
This will likely be the final servicing mission, as Hubble reaches the end of its working life. The plan now is to decommission and de-orbit sometime during the next decade, while preparing for the launching of its next-gen replacement, the James Webb Space Telescope, in 2013.
Source: NASA, Hubblesite.org
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