Launched: March 2009
Cost: $520 million.
Claim to fame: It will search the skies for distant planets, especially Earth-sized planets thought to be capable of supporting life. Astronomers have currently found more than 300 planets outside our solar system, but none has a size or orbit similar to Earth's.
Factoid: Kepler looks for tiny changes in a star's brightness to see if planets are crossing in front of it.
James Webb Space Telescope
Launched: Scheduled for 2014
Cost: $4.4 billion
Claim to fame: Billed as NASA's successor to Hubble, the Webb will search for some of the first galaxies ever formed and examine the atmospheres of planets outside the solar system. The telescope uses infrared light to see objects even farther away than a telescope that uses visible light.
Factoid: It will orbit more than 1 million miles away from Earth, in a position called the second Lagrange point.
Herschel Space Telescope
Launched: May 2009
Cost: $1-5 billion (including some operational costs)
Claim to fame: Like the coming Webb telescope, this European Space Agency telescope seeks to use infrared to look at the earliest galaxies in the universe. It will also look at clouds and dust where new stars form.
Factoid: The mirror on the telescope is billed as the largest ever launched. It's headed to the second Lagrange point in the Earth-sun system.
Chandra X-ray Observatory
Launched: July 1999
Cost: $1.5 billion
Claim to fame: It looks at the X-rays emitted from exploding stars, the matter around black holes and other locations.
Factoid: It has studied a massive black hole in the center of the Milky Way galaxy.
Fermi Gamma-ray Space Telescope
Launched: June 2008
Cost: $510 million
Claim to fame: It searches for powerful gamma rays that burst out from supermassive black holes, merging neutron stars and other sources.
Factoid: High-energy gamma rays pass right through mirrors and lenses, so conventional telescopes would not see them. A different technology is used.
Hubble Space Telescope
Launched: April 1990
Cost: $1.5 billion
Claim to fame: Hubble has taken sparklingly clear images of distant galaxies and helped scientists discover the unseen force known as "dark energy." It has taken "deep field" pictures showing thousands of galaxies in small portions of the sky.
Factoid: After this last and final repair mission, Hubble will probably be allowed to fall back to Earth within a decade.
Space shuttle astronauts returned to Earth eight days ago after a challenging repair mission to the Hubble Space Telescope. Their work means scientists can continue using Hubble to study mysterious concepts such as "dark matter" and "dark energy," and for brilliant photos that have made the telescope famous. What's less well-known is that Hubble is not alone. Europeans launched a space telescope last month and NASA plans another in 2014. Other telescopes already are orbiting Earth, looking into the heavens with visible light, as well as infrared, X-rays and gamma rays. "This is a very unique window of opportunity to have several telescopes working in concert," says Ray Villard of the Space Telescope Science Institute. He compares it to doctors who give you an X-ray as well as an MRI. The different techniques give doctors more information about your body — and astronomers more information about the universe. Here is a look at some, but not all, of the telescopes in space.