Hubble’s Space Telescope

1. Hubble’s Space Telescope • Hubble’s domain extends from the ultraviolet, through the visible, and to the near-infrared. With a primary mirror diameter of 2.4 meters (94.5 inches), Hubble would at most be considered a medium-size telescope on the ground. However, the combination of its precision optics, location above the atmosphere, state-of-the-art instrumentation, and unprecedented pointing stability and control, allows Hubble to more than make up for its lack of size. • The most detailed look at the farthest known galaxies in the Universe has been obtained by imaging from the Hubble Space Telescope. Spectroscopically, Hubble has detected several atomic constituents in the atmosphere of a planet outside our solar system.

2. Chandra X-Ray Observatory • The Observatory has three major parts: (1) the X-ray telescope, whose mirrors focus X-rays from celestial objects; (2) the science instruments which record the X-rays so that X-ray images can be produced and analyzed; and (3) the spacecraft, which provides the environment necessary for the telescope and the instruments to work. • Chandra gives astronomers a powerful tool to investigate the hot regions of the universe where black holes, exploding stars, and colliding galaxies holds way. X-ray telescopes can also trace the hot gas from an exploding star or detect X-rays from matter swirling as close as 90 kilometers from the event horizon of a stellar black hole.

3. Spitzer Space Telescope • NASA's Spitzer Space Telescope, studying the universe in infrared. • Consisting of a 0.85-meter telescope and three cryogenically-cooled science instruments, Spitzer is the largest infrared telescope ever launched into space. Its highly sensitive instruments give us a unique view of the Universe and allow us to peer into regions of space which are hidden from optical telescopes. Many areas of space are filled with vast, dense clouds of gas and dust which block our view. Infrared light, however can penetrate these clouds, allowing us to peer into regions of star formation, the centers of galaxies, and into newly forming planetary systems. Infrared also brings us information about the cooler objects in space, such as smaller stars which are too dim to be detected by their visible light, extrasolar planets, and giant molecular clouds. Also, many molecules in space, including organic molecules, have their unique signatures in the infrared. • Because infrared is primarily heat radiation, the telescope must be cooled to near absolute zero (-459 degrees Fahrenheit or -273 degrees Celsius) so that it can observe infrared signals from space without interference from the telescope's own heat. Also, the telescope must be protected from the heat of the Sun and the infrared radiation put out by the Earth. To do this, Spitzer carries a solar shield and was launched into an Earth-trailing solar orbit. This unique orbit places Spitzer far enough away from the Earth to allow the telescope to cool rapidly without having to carry large amounts of cryogen (coolant).

4. SOFIA • The Stratospheric Observatory for Infrared Astronomy--or SOFIA--is an airborne observatory that will complement the Hubble, Spitzer, Herschel and James Webb space telescopes, as well as major Earth-based telescopes. • Once it begins operations in about 2010, SOFIA'S 2.5-meter (100 inch) diameter reflecting telescope will provide astronomers with access to the visible, infrared and sub-millimeter spectrum, with optimized performance in the mid-infrared to sub-millimeter range. • By recording infrared measurements not possible from the ground, SOFIA will be able to observe occultations of stars by solar system objects to help determine the objects' sizes, compositions and atmospheric structures. It will help answer many fundamental questions about the creation and evolution of the universe, including how stars and planets are formed, how organic materials necessary for life form and evolve, and the nature of the black hole at the center of our Milky Way galaxy.

5. Kepler Telescope • NASA's Kepler spacecraft lifted off on March 6, 2009, sending the agency's first planet-hunting spacecraft on a three-and-a-half-year mission to seek signs of other Earth-like planets. • The Kepler instrument is a specially designed 0.95-meter diameter telescope called a photometer or light meter. It has a very large field of view for an astronomical telescope — 105 square degrees, which is comparable to the area of your hand held at arm's length. It needs that large a field in order to observe the necessary large number of stars. It stares at the same star field for the entire mission and continuously and simultaneously monitors the brightnesses of more than 100,000 stars for the life of the mission—3.5 or more years. • There is now clear evidence for substantial numbers of three types of exoplanets; gas giants, hot-super-Earths in short period orbits, and ice giants. The challenge now is to find terrestrial planets (i.e., those one half to twice the size of the Earth), especially those in the habitable zone of their stars where liquid water might exist on the surface of the planet.

6. The James Webb Space Telescope • The James Webb Space Telescope (JWST) will be a large infrared telescope with a 6.5-meter primary mirror.  Launch is planned for 2014. • JWST was formerly known as the "Next Generation Space Telescope" (NGST). JWST was renamed in Sept. 2002 after a former NASA administrator, James Webb. • There will be four science instruments on JWST: a near-infrared (IR) camera, a near-IR multi-object spectrograph, a mid-IR instrument, and a tunable filter imager. JWST's instruments will be designed to work primarily in the infrared range of the electromagnetic spectrum, with some capability in the visible range. • It will study every phase in the history of our Universe, ranging from the first luminous glows after the Big Bang, to the formation of solar systems capable of supporting life on planets like Earth, to the evolution of our own Solar System.