<P> The Infrared Astronomical Satellite (IRAS) was the first - ever space - based observatory to perform a survey of the entire sky at infrared wavelengths . It discovered about 350,000 sources, many of which are still awaiting identification . New discoveries included a dust disk around Vega and the first images of the Milky Way Galaxy's core . </P> <P> IRAS's life, like that of most of infrared satellites that followed after, was limited by its cooling system . To effectively work in the infrared domain, the telescope must be cooled to cryogenic temperatures . In IRAS's case, 73 kilograms of superfluid helium kept the telescope at a temperature of 2 kelvins (about − 271 ° C) by evaporation . The supply of liquid helium was depleted after 10 months on November 22, 1983, causing the telescope temperature to rise and preventing further observations . The spacecraft continues to orbit close to the Earth . </P> <P> The telescope was a joint project of the United States (NASA), the Netherlands (NIVR), and the United Kingdom (SERC). Over 250,000 infrared sources were observed at 12, 25, 60, and 100 micrometer wavelengths . </P> <P> The Magellan spacecraft was a space probe sent to the planet Venus, the first unmanned interplanetary spacecraft to be launched by NASA since its successful Pioneer Orbiter, also to Venus, in 1978 . It was also the first of three deep - space probes to be launched on the Space Shuttle, and the first spacecraft to employ aerobraking techniques to lower its orbit . </P>

Which of these planetary bodies was studied by voyager 1 brainly