Astronomy

About the James Webb Space Telescope



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The James Webb Space Telescope is an infrared telescope currently under development by NASA, with assistance from the Canadian Space Agency and the European Space Agency. Named after early NASA director James Webb, the telescope has been in development for many years but has finally been slated for launch in 2014 on an initial mission projected to last five years. As with most spacecraft, if the telescope is successful it should last for much longer.

- Spacecraft and Mission Profile -

The James Webb Telescope is intended to join the search for early stars and galaxies, the first generations to form after the Big Bang, as well as to study how galaxies, stars, and planetary systems form. These missions continue the ones originally carried out by the venerable Hubble Space Telescope.

However, the Hubble is aging and has only several years of operational life expectancy left. Its replacements, while far more advanced, are also much more narrowly specialized; thus, the James Webb Space Telescope is considered a replacement for the Hubble Space Telescope, but will only continue its mission in the infrared spectrum, not in the visible light which Hubble has used to create its characteristically extraordinary images of galaxies and planetary nebulae.

Infrared offers important advantages for studying extremely distant objects. However, it also requires special technology and preparation. The James Webb Space Telescope will operate at a temperature of about -390 degrees Fahrenheit, or -230 degrees Celsius, just a few dozen degrees above absolute zero. To do that, the spacecraft consists not only of the telescope itself but also a massive cooling shield, which will be positioned to block sunlight from reaching the sensitive components within the telescope. It will also be placed in solar rather than Earth orbit, at a point known as the L2 Lagrange point. This point lies roughly one million miles away from the Earth, on a line drawn directly from the Sun through the Earth. Keeping the Earth positioned between the Sun and the telescope at all times will help reduce the need for cooling and shielding.

- Current Plans -

The James Webb Space Telescope is a massive spacecraft, at 14,000 pounds and 79 feet long. The telescope itself has a diameter of 21 feet. To show off its technological achievement, NASA has constructed a full-scale public model which has been exhibited at various sites around the world but is currently at the Smithsonian. The total cost of the spacecraft is about $3.5 billion.

The telescope is currently under development, led by Grummann and NASA's Goddard Space Flight Centre. It is slated for launch from France's Kourou space centre in Guiana, aboard a French-built Ariane 5 rocket. The current tentative schedule calls for launch in June 2014, though launch date delays are common in space projects.

- Further Reading -

NASA. "The James Webb Space Telescope." Official Project Web Page.

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