Chapter 5.5

Astronomy from Space

115-123

The Hubble Space Telescope may be the most "famous" of space telescopes but it is by no means the only orbitting observatory. The history of "space telescopes" goes back to the late 1940's when the idea of an orbitting telescope was first discussed publicly by the American astronomer Lyman Spitzer. In the 1960's the first rocket borne telescopes made brief observations and by 1968 the first orbiting astronomical observatory was launced. In the intervening years dozens of "space telescopes" capable of observing across the entire electromagnetic spectrum have been launced.

Different Wavelength Regions from Space

Table 5.7 summarizes some of the space telescopes that have been put in orbit to study specific regions of the electromagnetic spectrum.

Region	Telescopes	Information	Key Science
Gamma	International Gamma-Ray Astrophysics Laboratory (INTEGRAL)	INTEGRAL was launced by the European Space Agency in 2002 and is the most sophisticated gamma-ray observatory to date	study most energetic processes in the universe (supernovae, gamma ray bursters)
Gamma	Compton Gamma-Ray Observatory (CGRO)	Launced in 1991, entered Earth's atmosphere 2000. While in operation was the first major orbitting gamma-ray observatory	study interacting binary star sytems cores of glaxies
X-ray	International X-Ray Observatory (IXO)	This international colloborative telescope will be launched in 2020 and replace the exisitng Chandra Observatory	supernovae and supernovae remnants black holes
X-ray	Chandra	The Chandra X-ray telescope was launched in 1999 and has provided breath taking images of the universe in the x-ray region ever since	evolution of galaxies structure of galaxies (nuclei)
Ultra-Violet	Far Ultra-Violet Spectroscopic Explorer (FUSE)	Launched 1999 - provides vital information in the far ultraviolet region	study hottest stars corona or sun and other stars
Ultra-Violet	Hubble Space Telescope (HST)	The Hubble Space Telescope is capable of working in the near UV	study of hot interstellar medium
Visible	The Hubble Space Telescope (HST)	The HST was launched in 1990 and has become an essential tool in modern astronomy for the near UV, visible and near IR regions of the spectrum. HST has provided some of the most dteailed and beautiful astronomical images ever produced.	formation of galaxies and galactic structure star formation solar system astronomy detection of Cepheid variables and supernovae in distant galaxies
Infra-red	Spitzer Space Telescope	Launched 2003, the Spitzer Space Telescope is optimized for work in the IR region and provides stunning imagery of the same.	star formation planetary (including extra-solar) astronomy evolution of warm interstellar medium
Infra-red	James Webb Space Telescope (JWST)	This will be 3 times the size of the Hubble Space Teelscope and be able to operate in the near to mid Infra-red. Scheduled to launch in 2013	galactic structure large scale structure of the universe
Microwave	Cosmic Background Explorer (COBE)	Launched 1989 to observe the universe in a very specific part of the microwave region	precise measurements of temperature variation across sky study earliest observable conditions afer Big Bang
Microwave	Wilkinson Microwave Anisotropy Probe (WMAP)	Was launched in 2001 and provides more than 30 time the resolution and 45 times the sensitivity of COBE	provide precise values of key cosmological parameters
Table 5.7

Table 5.7 provides a "snap shot" of only a small number of orbiting observatories. To get some idea of the kinds of images produced please refer to Chapter 5.1, Table 5.4.

To understand why some astronomical observations can only be done from orbit

Chp 6.4

A common misconception is that the value of space telescopes lies in "getting them closer" to the objects they study. This is not true - at altitudes of a few hundred km the telescopes are no closer in any practical sense. The real reason is that from space the interference of the Earth's atmosphere is eliminated.