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Fwd = Dramatic Change Coming In View Of The Universe

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  • Frits Westra
    Forwarded by: fwestra@hetnet.nl URL: http://unisci.com/stories/20001/0331002.htm Original Date: Sat, 1 Apr 2000 19:20:14 +0200
    Message 1 of 1 , Apr 2, 2000
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      Forwarded by: fwestra@...
      URL: http://unisci.com/stories/20001/0331002.htm
      Original Date: Sat, 1 Apr 2000 19:20:14 +0200

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      Dramatic Change Coming In View Of The Universe

      Astronomers looking at the very cold, far-infrared universe have
      barely glimpsed what's there. They've had to make do with imaging
      systems that survey the cosmos a few pixel points of light at a time.

      And they've had to grab opportunities to observe from space or high in
      the atmosphere, where the cosmic far infrared photons are visible.

      Things will change dramatically with the launch of the Space Infrared
      Telescope Facility (SIRTF) in December 2001.

      SIRTF will fly three science instruments in orbit around the sun for
      perhaps as long as five years -- as long as the liquid helium lasts to
      keep the imaging systems cooled to near absolute zero.

      One of the instruments, from the University of Arizona, will use the
      first true imaging arrays at far-infrared wavelengths. It will detect
      far-infrared objects 100 times fainter than have ever been seen
      before.

      Where pioneering far-infrared surveys of the 1980s-1990s saw nearly
      empty sky, SIRTF will get views packed with infrared-bright objects,
      said University of Arizona astronomer George H. Rieke.

      Rieke is principal investigator for the Multiband Imaging Photometer
      for SIRTF (MIPS), the science instrument for the far infrared. The
      MIPS is a highly sensitive camera that will take images of the coolest
      objects in space, objects at temperatures between about minus 430 and
      minus 300 degrees Fahrenheit.

      Next Monday, April 3, Rieke and his entire UA Steward Observatory team
      will be at Ball Aerospace in Boulder, Colo., to demonstrate that their
      instrument meets NASA's requirements. They will hand over the
      instrument officially a few weeks later.

      Then MIPS will be mounted in a helium dewar (a kind of sophisticated
      thermos bottle), cooled to 1.5 degrees Kelvin (or minus 457
      Fahrenheit, just above absolute zero), mounted with the dewar in the
      telescope and tested.

      The completed telescope with instruments gets shipped next year to
      Lockheed-Martin in Sunnyvale, Calif., where it will be installed in
      the spacecraft and further tested. The full SIRTF observatory will
      travel a few months before launch to the NASA Kennedy Space Center at
      Cape Canaveral, Fla.

      The Harvard-Smithsonian Center for Astrophysics (CfA) and Cornell
      University are on a similar schedule for the other two SIRTF science
      instruments. CfA has developed the Infrared Array Camera and Cornell
      has developed the Infrared Spectograph.

      Rieke's group began work on their camera in 1984, when SIRTF was
      envisioned as a $2 billion mission. The SIRTF design was overhauled in
      1994 to cut mission costs to under a half billion dollars. The UA team
      contracted to build MIPS for $23.7 million. Advances in infrared
      detectors allowed SIRTF to retain much of its power despite the huge
      budget cut.

      UA astronomer Erick T. Young, deputy principal investigator for MIPS,
      led the Steward Observatory team that designed and built the first
      far-infrared detector arrays for their part of the SIRTF mission. The
      arrays will enable MIPS to see far-infrared objects never seen before.

      "Such images will show us infrared-bright galaxies to the edge of the
      known Universe, maybe even farther than any galaxies we have
      discovered so far," Rieke said.

      "And we can look around nearby sun-like stars for planetary debris
      systems with emissions as wimpy as our own solar system emission.

      "In fact, we've shown that MIPS, looking back from any close star,
      could detect the finely-divided material we expect lies out in the
      Kuiper Belt," he added. The Kuiper Belt is the system of small, faint
      and very cold objects recently found beyond the orbits of Neptune and
      Pluto.

      But the real breakthroughs are up to the astronomical community, which
      will get 80 percent of SIRTF observing time, Rieke emphasized. The
      SIRTF Science Center at the California Institute of Technology will
      issue a first call for observing proposals a month from now.

      "With such an advance in capability, we expect that discoveries will
      be made well beyond our currently imagined ones," Rieke said.

      The UA camera on SIRTF contains three super-cooled detector systems
      that operate at different wavelengths.

      One array, supplied by Boeing North America, operates at 24 microns,
      50 times the wavelength of visible light. (A micron is one-thousandth
      of a millimeter.)

      Another far-infrared array, built at Steward Observatory, is sensitive
      to radiation at 70 microns. It contains 1,024 detectors, 100 times
      larger than previous arrays operating in space at this wavelength.
      Each detector has about 30 times the sensitivity of those in the
      earlier arrays.

      A third array, also built at Steward Observatory, operates at 160
      microns, about 300 times the wavelength of visible light. There are 10
      times as many detectors -- each 10 times more sensitive -- as in any
      previous array operated in space at this wavelength.

      All objects above the coldest possible temperature, absolute zero, or
      minus 459 degrees Fahrenheit, emit infrared radiation, or heat. Helium
      is used to chill the MIPS arrays to just 2 degrees Fahrenheit above
      absolute zero to avoid blinding the arrays with heat from SIRTF
      itself. - By Lori Stiles

      THE MIPS SCIENCE TEAM

      Eric Arens, University of California, Berkeley

      Charles Beichman, California Institute of Technology

      Steven Gaelema, Black Forest Engineering

      T.Nicholas Gautier, Jet Propulsion Laboratory

      Eugene Haller, Lawrence Berkeley National Laboratory

      Charles Lada, Harvard Smithsonian Astrophysical Observatory

      Frank Low, University of Arizona

      Jeremy Mould, Mount Stromlo & Siding Spring Observatory

      Gerry Neugebauer, California Institute of Technology

      Paul Richards, University of California, Berkeley

      Marcia Rieke, University of Arizona

      Peter Strittmatter, University of Arizona

      Michael Werner, Jet Propulsion Laboratory

      THE STEWARD OBSERVATORY TEAM

      Jeff Beeman - Detectors and Stimulators

      Michael Bradley-Focal Plane Construction

      Jim Cadien - Detector Testing

      Cindy Davidson - Process Engineer

      Jim Davis - Focal Plane Construction

      Chad Engelbracht - Instrument Scientist

      Kimberly Ennico - Instrument Science

      Karl Gordon - Instrument Science

      Dean Hines - Scientist-At-Large

      Todd Horne - Research Specialist

      Doug Kelly - Instrument Science

      Dak Knight - Focal Plane Construction

      Mary McCormick - Administrative Support

      Tom McMahon - Systems Engineer

      George Rieke - Principal Investigator

      Gil Rivlis - Software, Computers, and Miscellaneous

      Raz Quillen Rivlis - Destructive Test Consultant

      Rick Schnurr - Stressed Ge:Ga Array Lead

      John Stansberry - Instrument Science

      Patsy Van Buren - Administrative Support

      Debbie Wilson - Program Manager

      Greg Winters - Focal Plane Engineer

      Erick Young - Deputy Principal Investigator

      SIRTF MISSION MEMBERS

      Jet Propulsion Laboratory SIRTF Science Center, California Institute
      of Technology

      Ball Aerospace and Technologies Corp.

      Lockheed Martin Missiles and Space

      Smithsonian Astrophysical Observatory

      NASA-Goddard Space Flight Center

      Cornell University

      University of Arizona

      Related websites:
      [3]MIPS

      [4]SIRTF
      [Contact: [5]George H. Rieke, [6]Erick T. Young, [7]Lori Stiles]

      31-Mar-2000
      Click for Related Stories

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      References

      1. http://unisci.com/
      2. http://unisci.com/
      3. http://mips.as.arizona.edu/
      4. http://sirtf.jpl.nasa.gov/
      5. mailto:grieke@...
      6. mailto:eyoung@...
      7. mailto:lstiles@...

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