Science and Space

space and astronomy articles.

Ongoing Space Missions(3)

(This is the third part of the series "Ongoing Space Missions" in which I will try to inform the readers all about the spacecrafts still travelling or operating beyond near-earth orbit)

The Spitzer Space Telescope

Launched 25 August 2003

The objective -

to peer into regions of space which are hidden from optical telescopes.

Mission Basics-

Spitzer Space Telescope(formerly SIRTF, the Space Infrared Telescope Facility) was launched into an innovative Earth-trailing solar orbit. This means that it will not circle around the Earth. Instead, it will trail behind the Earth as the Earth orbits around the Sun. Spitzer will slowly drift away from the Earth at the rate of about 16,000,000 km per year.

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. 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 launched into an Earth-trailing solar orbit. This unique orbit places Spitzer far enough away from the Earth to allow the telescope to cool rapidy without having to carry large amounts of cryogen (coolant).

The ability to see astronomical objects will clearly depend on the luminosity (brightness) of those objects. The Spitzer Space Telescope expects to be able to see bright galaxies out to redshifts of z = 4 or more, which corresponds to about 11.5 billion light-years. Since the observable Universe is thought to be some 12-15 billion light-years in size, it should be apparent that Spitzer has the capability of observing objects in the very distant (and young) Universe.

Mission Cost- $720 million

End of Mission

Estimated Lifetime: 2.5 years (minimum); 5+ years (goal)

posted by: kyawoo at 19:52 | link | comments |
astronomy, unmanned missions

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