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The James Webb Space Telescope (JWST)


Named after a former NASA administrator, the James Webb Space Telescope (JWST) is a large, infrared-optimized space telescope, scheduled for launch in 2014. JWST will find the first galaxies that formed in the early Universe, connecting the Big Bang to our own Milky Way Galaxy. JWST will peer through dusty clouds to see stars forming planetary systems, connecting the Milky Way to our own Solar System. JWST's instruments will be designed to work primarily in the infrared range of the electromagnetic spectrum, with some capability in the visible range.

JWST will have a large mirror, 6.5 meters (21.3 feet) in diameter and a sunshield the size of a tennis court. Both the mirror and sunshade won't fit onto the rocket fully open, so both will fold up and open once JWST is in outer space. JWST will reside in an orbit about 1.5 million km (1 million miles) from the Earth.

The Space Telescope Science Institute (STScI) is responsible for the Science and Operations Center (S&OC) for the JWST (in a similar fashion as for HST) and as such plays an important role in the development of the JWST. The goals of the project are divided into four key themes:

  1. First Light - The moments following the Big Bang

  2. Assembly of galaxies - History of star formation

  3. Birth of Planetary Systems

  4. Origins of life - The study of the outer Solar System

The science goals indicated briefly above require a versatile mid-infrared instrument with a wide field of view for imaging through broad and narrow band filters, low resolution spectroscopy from 5-10μm, moderate resolution spectroscopy with R ~ 3000, and high dynamic range coronography. MIRI is designed to provide this science capability for a lifetime requirement of 5 years after the completion of commissioning.

To avoid swamping the very faint astronomical signals with radiation from the telescope, the telescope and its instruments must be very cold. Therefore, JWST has a large shield that blocks the light from the Sun, Earth, and Moon, which otherwise would heat up the telescope, and interfere with the observations. To have this work, JWST must be in an orbit where all three of these objects are in about the same direction.



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