Infrared Views of the Solar System from Space 683
telescopes were developed. Somewhat larger strips of the
sky were observed by small aperture, rocket-borne tele-
scopes with tantalizing results. Only by getting above the
atmosphere with a cooled telescope would it be possible
to study the sky on a large scale at these wavelengths. This
was achieved on January 26, 1983, with the launch of the
Infrared Astronomical Satellite(IRAS). It was the first in
a series of space-based infrared telescopes, the latest of
which include theSpitzer Space Telescopeand Japanese
Akarisatellite (Fig. 2, Table 1).FIGURE 2 Spacebased infrared telescopes in Earth orbit include (a) the Infrared Astronomical Satellite
(IRAS) in 1983, (b) the Cosmic Background Explorer, 1989–1990, (c) the European Infrared Space
Observatory (ISO), 1995–1998, (d) the US Air Force Midcourse Space Experiment (MSX), 1996–1997,
and (e) the Japanese Akari spacecraft, launched in 2006. The Spitzer Space Telescope (f) was launched
into a heliocentric orbit in 2003 and is expected to operate for five years.