A NASA observatory will soon open a new window to the universe. By using infrared technology to study celestial objects, which are either too cool, too dust-enshrouded or too far away to otherwise be seen, NASA’s Space Infrared Telescope Facility (SIRTF), will pierce the thick dust that permeates the universe.
From its Earth-trailing orbit around the sun, SIRTF, set to launch on April 18, will unveil new information about galaxies, stars, and dusty discs around nearby stars, which may be “planetary construction zones.”
“The Space Infrared Telescope Facility will complete NASA’s suite of Great Observatories, a program that includes three previous missions that studied the universe with visible light, X-rays and gamma rays,” said Dr. Ed Weiler, NASA’s associate administrator for space science. “Many cosmic objects produce radiation over a wide range of wavelengths, so it’s important to get the whole picture,” he said. The three previous Great Observatories are the Hubble Space Telescope, Compton Gamma Ray, and Chandra X-ray Observatories.
By studying the structure and composition of dusty planet-forming discs around stars, SIRTF will aid the search for Earth-like planets that may harbor life. This makes it a cornerstone of NASA’s Origins Program, which seeks to answer the questions, “Where did we come from? Are we alone?”
Infrared detectors can see longer wavelengths than the red light visible to our eyes. As the universe expands, starlight from distant galaxies is shifted from blue to red and, ultimately, into the infrared. Most radiation emitted by stars, galaxies and other objects in the early universe now lies in the infrared. The SIRTF will enable scientists to look farther back in space and time than was previously possible.
“With this mission, we will see the universe as it was billions of years ago, helping us pinpoint how and when the first objects formed, as well as their composition,” said Dr. Anne Kinney, director of the astronomy and physics division at NASA Headquarters.
“The observatory will give us a better understanding of the universe and our place within it,” said Dr. Michael Werner, the mission’s project scientist at JPL. “For example, interstellar space has lots of carbon-rich organic molecules. Understanding these may illuminate the processes by which life formed,” he said.
During its two-and-one-half to five-year mission, the SIRTF will also study brown dwarfs, or cool, “failed stars.” Some scientists think brown dwarfs may account for some or all of the elusive “dark matter” thought to be prevalent in the universe. The mission will also study planets in our own solar system, asteroids and comets.
The observatory’s telescope has three science instruments. The infrared array camera is a general-purpose camera for near-to- mid-infrared wavelengths. The infrared spectrograph breaks light into its various wavelengths, much like a prism, to help astronomers study the composition of cosmic objects. The multi-band imaging photometer will gather pictures and limited spectroscopic data at far-infrared wavelengths to study cool, dusty objects.
The spacecraft features several technological breakthroughs, and the out-of-the-ordinary mission design will pay dividends as well. “The innovations have substantially reduced mission development costs,” said Project Manager Dave Gallagher at JPL. “For example, the mission’s Earth-trailing orbit simplifies scheduling and operations. Because the telescope detects heat from relatively cool objects, we have to keep it extremely cold. We’ve found a more efficient way to cool the telescope and slash the amount of liquid helium the observatory must carry,” Gallagher said. The mission’s technologies and science discoveries will help enable future Origins missions, such as the James Webb Space Telescope and Terrestrial Planet Finder.
JPL manages the SIRTF mission for NASA’s Office of Space Science, Washington, and conducts flight operations. NASA’s Goddard Space Flight Center is responsible for building the Infrared Array Camera. The SIRTF Science Center at the California Institute of Technology, Pasadena will handle all aspects of science operations, including data processing. Lockheed Martin Space Systems Company, Sunnyvale, Calif., is responsible for spacecraft design and development, observatory systems engineering, integration and testing. Ball Aerospace and Technologies Corporation, Boulder, Colo., is responsible for the design and development of the cryo-telescope assembly, integration of the science instrument cold assemblies into the cryostat, and is subcontractor for two science instruments.
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