by Mike Mcnaulty
As the earth slowly completes yet another revolution on its axis the curtain slowly closes on the stage that is our world and then just as slowly re-opens. Day has become night and on those nights when the sky is clear we are given the opportunity to explore the greatest light show on earth but what about those objects that aren't visible by the naked eye or the most powerful earth based telescopes or even the Hubble? Celestial bodies that Physics and Astronomy (in theory) insist must exist but we simply cannot see, enter The James Webb Space Telescope (JWST or The Webb Telescope). The Webb telescope is the next generation of space based observatory's that will photograph the universe that lies beyond the horizon from deep space.
The JWST is a 3 way collaboration between NASA, The European Space Agency and The Canadian Space Agency. It is being built by Northrop-Grumman and Ball Aerospace and is scheduled for launch in 2014 aboard an Ariane 5 rocket but that's still a few years off, for now lets focus on the JWST's background and its mission. The Webb telescope is named after NASA's second administrator James Edwin Webb (1906-1992) who between February of 1961 and October of 1968 headed up the agency.
During those years Mr Webb oversaw the Mercury and Gemini space programs and was the agency's director up to the Apollo manned missions. Probably the darkest day of Mr Webb's tenure occurred on January 27th, 1967 during a test of the Apollo 1 spacecraft on launch pad 34 at what was then called Cape Canaveral. A flash fire swept through the cabin of the spacecraft trapping and killing astronauts Virgil "Gus" Grissom, Edward H. White and Roger B. Chaffee. Despite this tragic accident Mr Webb left a legacy at NASA as a man who profoundly believed in space exploration and who was dedicated to the Space Agency and its goals.
The primary mission of the Webb telescope will be to locate and photograph galaxies that formed during the early stages of the universe thus connecting our own Milky Way galaxy to the Big Bang Theory. The tele-scope will also gaze through dusty clouds to find stars forming solar systems this information will help scientists further understand the relationship of our galaxy to our own planetary system. The images and data collected will also help scientists better understand the time line of the universe. The JWST much like its predecessor the Hubble will use a large mirror to gather any and all available light for its imaging but unlike the Hubble the Webb's mirror will be nearly three times the size of the HST's.
The increase in the size of the mirror is necessary due to the region of space that the Webb will be operating in unlike the Hubble which stayed in the earth's low orbit (roughly 300 miles above earth) the Webb will be approximately one million miles away from the earth thus the larger mirror will help it focus and photograph distant objects. Protecting the mirror will be a sun shield, this shield which is roughly the size of a tennis court will be permanently positioned to block the sun's radiation from the telescope. The Webb will function almost exclusively in the ultraviolet range of the electromagnetic spectrum but it does have some limited ability in the visible range.
The Webb will have four scientific instruments onboard.
(1) The Mid Infrared Instrument (MIR) which will help to increase the telescopes wavelength coverage.
(2) The Near Infrared Camera (Nir Cam) will search for the early signs of star and galaxy formation as well as supernovas and the light curves that are given off by these exploding stars in addition to these tasks it will also map dark matter by gravitational lensing and will also be used for wave front sensing to help control the primary mirror.
(3) The Near Infrared Spectrograph (NirSpec) will provide wide field and deep imaging of the spectra given off by up to 100 different objects simultaneously in a 3x3 arc minute field of view.
(4) The Turntable Filter Imager (TFI) will be used primarily for scientific observations. The Webb telescope unlike the Hubble will not be serviceable due to its L2 orbit, L2 is an orbital path between the earth and the sun that allows an object to maintain a constant distance from the earth. So the instruments it takes with it will be the only ones it ever has if they become inoperable they will be no way to repair them.
The latest cost figure for the Webb is put at $6.5 billion at this amount the project is $1.5 billion over what was budgeted for it. At the time of the projects inception no allowances were made for cost overrun which makes no sense given the scale of the project and the enormous amount of technical input required. These cost overruns will of course somehow be absorbed just the same way they were for the Hubble and the Webb will eventually get to its new home in outer space.
The Webb, once it reaches its L2 orbit and starts to operate on its own will be managed by the Space Science Telescope Institute (STScI) in Baltimore, MD. The Institute will be responsible for the daily operation of the telescope and will also be in charge of the distribution of the data collected to the scientific community. We're not sure what exactly lies beyond what the Hubble could not see only time will tell but all indications point to that the JWST will be sending back photos of objects that will not only fascinate but will also educate us about a universe that is forever expanding.http://www.jwst.nasa.gov/orbit.html http://www.stsci.edu/jwst/instruments/