Stratospheric Observatory for Infrared Astronomy
The Stratospheric Observatory for Infrared Astronomy (English Stratospheric Observatory For Infrared Astronomy ) ( SOFIA ) is an airborne telescope, which NASA has developed together with the German Aerospace Center (DLR ) for infrared astronomy. For a reflecting telescope was installed aboard a modified Boeing 747SP.
Description
SOFIA is designed for an operating life of 20 years. The aircraft is operated by NASA DAOF (Dryden Aircraft Operations Facility) in Palmdale, California. At three to four nights a week on up to eight hours shall be observed from 12 to 14 km altitude. Once a year should SOFIA will be stationed in Germany for two weeks at Stuttgart Airport. SOFIA will replace its predecessor, the Kuiper Airborne Observatory ( KAO), which was in use from 1974 to 1995. Infrared telescopes that are mounted on aircraft, bring several advantages. On the one hand they fly above the troposphere, which absorbs much of the infrared radiation. On the other hand, the costs for maintenance are low, and improved technique is more easily retrofitted as telescopic satellites. Also, is the period of operation for aircraft -mounted telescopes 20 years, as opposed to satellite telescope, where the helium is depleted to cool after a few years.
History
After rumors about the termination of the project in early 2006, the continuation of the project was officially confirmed by NASA in July 2006. The first flight after the rebuild took place in Waco on April 26, 2007. On 21 May 2007 baptized Erik Lindbergh, grandson of Charles Lindbergh, the aircraft again as Clipper Lindbergh. The base of the aircraft was moved to Palmdale in January 2008 by the Dryden Flight Research Center Dryden Aircraft Operations Facility.
The first test flight with open telescope door was held in December 2009, the first test flight with use of the telescope, the so-called " first light ", on 26 May 2010.
The first scientific observation flight was successfully carried out from 30 November to 1 December 2010. SOFIA launched by NASA Dryden Aircraft Operations Facility in Palmdale, California and led with the infrared camera ( FORCAST - Faint Object InfraRed Camera for the SOFIA Telescope ) by observations at altitudes of about 13 km. Observation target was the constellation Orion. The full functionality is planned for 2014; It is then about 160 inserts with about 1000 hours of observation planned annually.
On March 4, 2014, NASA announced muster any further funding more for the SOFIA project and want to mothball the aircraft in 2015, if no partner assumes the costs. The Board Chairman of the DLR, the project would like to continue, Johann -Dietrich Wörner, revealed in an interview with the Mirror, " shocked and angry" about the decision of NASA.
The aircraft
As a carrier of the telescope a Boeing 747SP, which has a shorter fuselage, a larger maximum altitude and a greater range than the basic version 747-100/200 serves. The Boeing 747SP is so fly away in 12-15 km above 99 percent of the observations interfering water vapor. The selected machine with the registration N747NA completed on 25 April 1977 as the 306th B747 built its first flight and was delivered shortly afterwards at their customer Pan Am. In May 1977, the 50th anniversary of the first solo flight across the Atlantic by Charles Lindbergh, his widow, Anne Morrow Lindbergh christened the aircraft Clipper Lindbergh on the name. In February 1986, United Airlines took over the machine for which they flew until the end of 1995. NASA bought the 747 in 1997 and began with the tags and test flights in Waco, Texas. Behind the left-hand wing, a door has been cut into the body to be opened for the operation to allow the telescope to look upward. The telescoping section is separated by a pressure bulkhead of the other cabin, in addition to the three-member cockpit crew of up to 15 scientists, technicians and observers work.
The telescope
In the rear fuselage area of B747SP a product manufactured by the German company MAN Technologie AG and Kayser- Threde Nasmyth telescope is built, structurally a combination of a Newtonian telescope and a Cassegrain telescope. As with the latter, the rays from the convex secondary mirror are reflected in the direction of the primary mirror, but turned to the side, by a third flat-ground levels by 90 ° before it is reached. The last portion of the beam path to the focal point ( Nasmyth focus) coincides with the tilt axis of the telescope and the longitudinal axis of the aircraft and is thus stationary. How can undergo several successively arranged measuring instruments the rays received. To set the correct right ascension makes essentially the appropriate heading of the Boeing.
The use of height above the troposphere and a spectral range of the telescope from 0.3 microns to 1600 microns allow observations over a wide infrared range, which is for ground-based observatories due to absorptions mainly by water vapor contained in the troposphere only partially accessible in the infrared window.
The primary mirror has a diameter of 270 centimeters and a - by the shading (obstruction ) of the two smaller mirror - effective aperture of 250 centimeters. The with frame, bearings and additional instruments around 17 ton telescope was installed in February 2004 and for the first time directed on the night of August 19, 2004 to the sky. In this case, the aircraft was still in its soil.