Mar 12 1983
From The Space Library
Launched January 25, IRAS had already discovered up to 20 distant galaxies too small to see previously. Dr. James Houck of Cornell University, one of 18 astronomers on the three-nation IRAS science team, said at JPL that only 20 small galaxies outside the Milky Way were measured before IRAS went into orbit. "In 12 hours of operation with this satellite, we doubled that number" In a single minute, the 22.4-inch IRAS telescope found out more about the Large Magellanic Cloud, galaxy closest to the Milky Way, than ever discovered by Earth telescopes.
The IRAS telescope, cooled by liquid helium to 2.5 ° above absolute zero to offset any stray heat that might confuse its imaging, was so sensitive that it could detect an object with temperatures far below that of freezing on Earth. Optical telescopes, by contrast, could see only objects with temperatures hot enough to make them shine (above 10,000°F). The telescope was built in the United States, the spacecraft in the Netherlands; Great Britain was tracking it.
The biggest surprise, said Houck, was that the $80 million satellite was "working better than we had hoped," seeing cooler objects in greater detail than astronomers thought possible. Over its 12-month lifetime, IRAS could survey 95% of the sky in the infrared, never attempted from the ground. Infrared light waves were longer than those in the visible spectrum but shorter than radiowaves. The projected lifetime would probably be extended by 50% because of the slow rate of helium use so far. (W Post, Mar 12/83, A-l0)
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