Scientists
are busy preparing for Spring 2010's "First Light" flight of NASA's
Stratospheric Observatory for Infrared Astronomy (SOFIA), a highly modified
Boeing 747SP with a 2.5 meter (8.2 feet) diameter infrared telescope.
A team of
international partners is developing eight instruments that will enable SOFIA
to study the universe primarily in the infrared spectral band, but with
capabilities extending from wavelengths of 0.3 to 1600 microns, across
ultraviolet, visible, infrared, and sub-millimeter ranges.
"Working
with our German colleagues, we are eagerly anticipating SOFIA's
First Light flight," said Erick Young, SOFIA's recently appointed director
of Science and Mission Operations. "SOFIA will be a discovery engine for the next
20 years, and our collaborator teams have spent a number of years perfecting
these powerful scientific instruments."
Four of the
new
instruments are now ready for use on the airborne observatory. They include
a mid-infrared camera developed at New York's Cornell University known as the
Faint Object infraRed Camera for the SOFIA Telescope, or FORCAST (operating a
wavelengths of 5-40 microns); a heterodyne spectrometer called the German
Receiver for Astronomy at Terahertz Frequencies (GREAT – 60-200 microns)
developed at the Max Planck Institute for Radioastronomy, Bonn, Germany; the
Lowell Observatory's High-Speed Imaging Photometer for Occultations, or HIPO
(0.3 to 1.1 microns); and the Far-Infrared Field-Imaging Line Spectrometer
(FIFI-LS, 42-210 microns) developed at the Max Planck Institute for
Extraterrestrial Physics, in Garching, Germany.
Following
the first four instruments will be the CAltech Submillimeter Interstellar Medium
Investigations Receiver (CASIMIR), another heterodyne spectrometer (250-600
microns) being built at Caltech, Pasadena, Calif.; the High-resolution Airborne
Wideband Camera (HAWC), a far infrared bolometer camera (50-240 microns)
developed by the University of Chicago; Echelon-Cross-Echelle Spectrograph
(EXES), an echelon spectrometer (5-28 microns) under construction at the
University of California at Davis; and the First Light Infrared Test Experiment
CAMera (FLITECAM), a near infrared camera (1-5microns) developed at UCLA.
Three of
the first nine instruments have been thoroughly tested on ground-based
telescopes – HIPO at the Lowell Observatory in Arizona, FLITECAM at the
University of California's Lick Observatory, and FORCAST on Caltech's Mt. Palomar
five-meter telescope. HIPO has also been mounted on SOFIA's telescope and used
to observe celestial objects from the ground to test the observatory's systems.
FORCAST is slated for installation on SOFIA's First Light flight, when photons
from a celestial object come down the telescope tube for the first time while
the aircraft is airborne.
GREAT,
which has been tested in a lab environment, awaits its flight opportunity where
it will be able to demonstrate its capabilities. This spectrometer has not yet
been tested onboard SOFIA because it analyzes infrared wavelengths that are
entirely inaccessible from the ground.
SOFIA will fly with
one instrument fitted to the telescope for each airborne observation period.
When flying science missions, SOFIA cruises between 39,000 and 45,000 feet at a
speed of Mach 0.8 (520 mph) on seven- to nine-hour observing flights. In full
operations the observatory will fly typically three nights per week for
approximately 1,000 hours of observing time each year. SOFIA's telescope weighs
34,000 pounds and was built in Germany by MAN Technologie AG and Kayser-Threde
GmbH. It has an elevation range of 20 to 60 degrees above the horizon, and an
unvignetted field-of-view diameter of 8 arcmin (a quarter the diameter of the
full moon).
SOFIA is
the successor to NASA's extremely successful Kuiper Airborne Observatory
(KAO), a modified Lockheed C-141 fitted with a one-meter infrared telescope.
KAO operated from NASA Ames from 1974 to 1995, and made such astronomical
discoveries as the rings around the planet Uranus, the atmosphere surrounding
the planet Pluto, and the presence of water vapor in the interstellar medium.
The new observatory is a joint NASA and German Space Agency
(Deutsches Zentrum fur Luft- und Raumfahrt – DLR) project. The program
is managed at NASA's Dryden Flight Research Center with the aircraft based at
the Dryden Aircraft Operations Facility in Palmdale, Calif. NASA's Ames
Research Center in Mountain View, Calif., manages SOFIA science and mission
operations in cooperation with the Universities Space Research Association
(USRA) and the Deutsches SOFIA Institute (DSI) in Stuttgart, Germany.
To learn
more about SOFIA, visit these websites: http://www.nasa.gov/mission_pages/SOFIA/index.html, www.sofia.usra.edu
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