About the Spitzer Space Telescope

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What is the Spitzer Space Telescope?

The Spitzer Space Telescope is a space-borne infrared telescope designed to study planets, comets, stars, galaxies, and other objects in the Universe. You can think of it as being the infrared version of the Hubble Space Telescope.
When was the Spitzer Space Telescope launched into space?
In August 2003.
Where was the Spitzer Space Telescope launched from?
The Spitzer Space Telescope was launched on a Delta rocket from the Kennedy Space Center at Cape Canaveral, Florida.
What type of orbit will Spitzer be launched into?
The Spitzer Space Telescope 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.
If the Spitzer Space Telescope is slowly drifting away from us, but sharing the Earth's orbit around the Sun, won't it eventually crash into us?
The Spitzer Space Telescope will drift all the way around Earth's orbit and back to the Earth about 60 years after it is launched. Many of the instruments will no longer be functioning by then because the liquid helium will have run out. Spitzer is so small that when it hits the Earth's atmosphere, it will burn up before it reaches the surface of the Earth. There is no danger to worry about.
How big is the Spitzer Space Telescope?
Astronomers typically characterize the size of a telescope by the diameter of its primary mirror. The Spitzer Space Telescope mirror is 0.85 meters in diameter. While this may seem small compared to telescopes on Earth (some of which reach 8-10 meters in diameter), Spitzer will be in space and hence will not suffer from the atmospheric distortion. In general, a smaller telescope in space can replicate the capabilities of a larger telescope on Earth. Despite its modest size, Spitzer is the largest infrared telescope ever put into space. The entire Observatory has a mass of about 935 kilograms, or about 2000 pounds.
Why was a solar orbit chosen?
Since the Spitzer Space Telescope is measuring weak thermal radiation (heat) from distant objects, it must be refrigerated to reduce the contaminating heat emitted by the telescope itself. To further reduce this thermal "noise" we also want to place Spitzer away from the heat-producing Earth. By launching into deep space, the ambient (surrounding) temperatures are reduced from about 250-300 Kelvin in Earth orbit (250-300 degrees above absolute zero, which is about minus 273 degrees Celsius and minus 460 degrees Fahrenheit) to about 35 Kelvin.
What is the advantage of being in a colder deep space environment?
Since the Spitzer Space Telescope must operate at the frigid temperature of only 5.5 K, it has to carry its own supply of cryogen (or refrigerant), and a cryostat ("Thermos bottle") to hold the liquid helium. By immersing Spitzer in a very cold environment to begin with, the Observatory can carry far less liquid helium than if it were orbiting the warm Earth.
How far will the Spitzer Space Telescope be able to see?
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.
What kinds of science will the Spitzer Space Telescope study?
The Spitzer Space Telescope will have the capability to study almost all types of objects in the Universe, ranging from our own Solar System, to stars in our Milky Way Galaxy, and to other distant galaxies in the Universe.
Will the Spitzer Space Telescope discover planets around nearby stars?
Neither the Spitzer Space Telescope, nor any existing telescope, has the resolving power (visual acuity) to directly image "extrasolar" planets around other stars. However, Spitzer will be able to detect and characterize flattened disks of dust around nearby stars. These dusty disks are presumed to be young planetary systems in the process of formation. In a sense, images of these disks represent snapshots of what our own Solar System may have looked like 4.5 billion years ago. NASA's Origins Program is designed to ultimately build an observatory in about 10-15 years to directly image Earth-sized planets around nearby stars.
How much will the Spitzer Space Telescope cost?
When the Spitzer Space Telescope was first designed, it was going to cost over two billion dollars. Due to some clever design and orbit changes the total cost has dropped to $720 million, which includes all costs from 1996 through launch and initial checkout, including early concept and feasibility studies. To learn more about how the cost of Spitzer was reduced click here.

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