Science Instruments Ready for SOFIA Airborne Telescope
NASA's SOFIA flying observatory was captured in striking relief during nighttime telescope characterization tests in Palmdale, Calif., in March 2008.
Credit: NASA/DFRC.

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