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. For more information about SIRTF on
the Internet, visit:
