IRAS

A special tool went into space in 1983.

It was a telescope that looked at the whole night sky. It used special light to see things we cannot see. It found many stars and dust clouds.

The tool found six comets. It also found three asteroids. These are big rocks in space.

It had to stay very cold to work. It used a cold liquid to keep cool. After ten months, the liquid ran out. The tool could not see anymore.

It still orbits the Earth today. It helped us learn so much about space.

In 1983, a new tool went into space. It was called IRAS. This was a special telescope. It was the first to study the whole night sky using infrared light. Infrared light is a type of light we cannot see with our eyes.

IRAS found many things in space. It saw about 350,000 different objects. Some were starburst galaxies. These are galaxies that make many new stars. It also found dust disks around stars. These disks might help make new planets. IRAS even found six comets and three asteroids. One asteroid was named Phaethon.

To work well, the telescope had to stay very cold. It used a liquid called helium to stay cool. This was the first time a superfluid was used in space. A superfluid is a special kind of liquid. The helium ran out after ten months. This made the telescope too warm to see infrared light. Even so, IRAS was a great success. It helped lead to new tools like the Spitzer Space Telescope.

The Infrared Astronomical Satellite, or IRAS, was a special tool for space. It was the first telescope to look at the whole night sky using infrared light. This is a type of light that human eyes cannot see.

IRAS helped us learn about many hidden things in space. It was a joint project between the United States, the Netherlands, and the United Kingdom. The mission lasted for ten months after it launched on 25 January 1983. It was a huge success for science.

To work well, the telescope had to stay very cold. It needed to reach cryogenic temperatures to see infrared light.

IRAS used a special liquid called superfluid helium to stay cool. The helium would evaporate to keep the telescope at a low temperature. This was the first time anyone used a superfluid in space. After ten months, the helium ran out on 21 November 1983. This caused the temperature to rise, so the telescope could no longer make observations.

Many scientists worked hard to study the data from IRAS. A team at the California Institute of Technology helped process the information. Jack Meadows led a team at Leicester University to look for moving objects. They included researchers John K. Davies and Simon F. Green. They looked at objects that the telescope had rejected. This hard work led to many new discoveries in our solar system.

IRAS found about 350,000 different sources in the sky. About 75,000 of these were starburst galaxies. These are galaxies that are still in a stage of making stars. It also saw dust disks around stars like Vega. These disks might be the early stages of making planets. The telescope also found three asteroids and six comets. One asteroid was named 3200 Phaethon. Some comets found were 126P/IRAS and 161P/Hartley–IRAS.

The work done by IRAS led to even better tools. Its success helped create the Spitzer Space Telescope, which launched in 2003. Other missions like the Infrared Space Observatory also followed. Later, a telescope called WISE launched in 2009 to study the sky again. Even today, the IRAS archive is kept at the Infrared Science Archive. The mission showed us how much we can learn by looking at the sky in new ways.

The Infrared Astronomical Satellite, known as IRAS, was a pioneering space telescope. It was the first observatory to perform a complete survey of the entire night sky using infrared wavelengths. Infrared light is a type of radiation that is invisible to the human eye. By looking at these wavelengths, IRAS could see objects that normal telescopes might miss. This mission was a major international effort. It was a joint project between the United States (NASA), the Netherlands (NIVR), and the United Kingdom (SERC).

To function, the telescope required a very specific environment. It had to be cooled to cryogenic temperatures to detect faint infrared signals. IRAS used a special substance called superfluid helium to achieve this cooling. The helium would evaporate to keep the telescope at a stable, extremely low temperature. This mission marked the first time a superfluid was used in space. However, this cooling system also limited the mission's lifespan. Once the liquid helium was depleted, the telescope temperature rose. This prevented any further observations. The on-board supply ran out on 21 November 1983, after ten months of operation.

The telescope operated by scanning the same regions of the sky multiple times. This allowed it to catalog fixed sources with high accuracy. IRAS mapped 96% of the sky four times. It observed at four specific wavelengths: 12, 25, 60, and 100 micrometers. The resolution of these observations varied depending on the wavelength used. At 12 micrometers, the resolution was 30 arcseconds. At 100 micrometers, the resolution was 2 arcminutes.

IRAS discovered approximately 350,000 different infrared sources. Many of these objects are still waiting to be identified by scientists. Among these discoveries were about 75,000 starburst galaxies. These are galaxies that are currently in a stage of intense star formation. The telescope also observed many normal stars surrounded by disks of dust. Scientists believe these disks may represent the early stages of planetary system formation. Notable examples include a dust disk discovered around the star Vega. IRAS also provided the first images of the core of our Milky Way galaxy.

Beyond deep space, IRAS also helped us understand our own solar system. While the telescope was designed for fixed sources, researchers looked closer at the data. Jack Meadows led a team at Leicester University to search for moving objects. This team included John K. Davies and Simon F. Green. They searched through sources that the system had initially rejected. This effort led to the discovery of three asteroids. One important discovery was 3200 Phaethon, which is an Apollo asteroid. It is also the parent body of the Geminid meteor shower.

The mission was also very successful in finding comets. IRAS discovered six comets in total. Four of these were long-period comets, and two were short-period comets. Specific discoveries included 126P/IRAS and 161P/Hartley–IRAS. Another was the comet IRAS–Araki–Alcock, which made a close approach to Earth in 1983. In 1983, IRAS accounted for six of the 22 total comets discovered or recovered that year. This was a significant achievement for that era of astronomy.

In December 1983, IRAS briefly made headlines with a mysterious discovery. Scientists announced an "unknown object" that appeared very large. Some thought it might be as large as the planet Jupiter. There was even concern it was close enough to be part of our solar system. However, further analysis corrected this idea. Of the unidentified objects, nine were actually distant galaxies. The tenth object was identified as intergalactic cirrus. None of them were bodies within our solar system.

The legacy of IRAS paved the way for many future space missions. Its success inspired the 1985 Infrared Telescope (IRT) mission on the Space Shuttle. It also led to the development of the Space Infrared Telescope Facility (SIRTF). This project eventually became the Spitzer Space Telescope, which launched in 2003. Other missions like the Infrared Space Observatory and the Hubble Space Telescope's NICMOS instrument also followed this path. More recently, the Wide-field Infrared Survey Explorer (WISE) provided results hundreds of times more sensitive than IRAS. The data from IRAS remains valuable today in the Infrared Science Archive at IPAC.