July 01, 2013
PALMDALE, Calif. — Sofia, the Boeing 747SP-based Stratospheric Observatory For Infrared Astronomy, is poised for its first mission to the southern hemisphere to allow astronomers to view the center of the galaxy.
The deployment to New Zealand, which begins in July, comes as Sofia developers NASA and the German Aerospace Center (DLR) continue to ramp up the pace of observing missions with the flying telescope, which is on track to become fully operational as early as October. Once Sofia is fully commissioned, scientists will be able to conduct up to four missions per week, NASA says.
Although the airborne telescope began initial science flights in 2011, the full capability of the observatory hinges on the completion of a suite of infrared (IR) instruments that are in the final phases of operational testing and commissioning. Sofia is intended for a 20-year service life and is approaching full capability just in time to fill a vacancy in infrared astronomy caused by the retirement of the European Space Agency’s Herschel telescope last month. “Now that Herschel is off line, that leaves a big gap which only Sofia can fill,” says NASA Sofia Platform Project Manager Brent Cobleigh.
“We’re looking to turn the corner from development to becoming fully operational,” Cobleigh says. “We are starting to see the fruits from the 2011 flights and the data is starting to come in, but we still have a few instruments to commission. We have completed commissioning three, and the fourth will be in September. When that gets done, that’s the criteria for full operational capability. We will have a full suite of instruments, although there are still a few new ones in the pipeline as well as modification of the current systems with things like cryo-coolers,” he adds.
Sofia is equipped with a 2.5-meter-dia. (8.2-ft.) IR telescope housed in a large cavity built into the aft fuselage of the modified 747SP. Large doors open in flight to allow the telescope to operate at altitudes up to 43,000 ft., avoiding 99% of the water vapor in the atmosphere that otherwise limits the effectiveness of Earth-based IR detectors. The various instruments attach to the telescope inside the pressurized main cabin of the aircraft.
“We just finished commissioning Forcast (Faint Object Infrared Camera for the Sofia Telescope) and we are now getting into full-science flights with that,” Cobleigh says. The fourth instrument will be Flitecam (First Light Infrared Test Experiment Camera), a near-IR test instrument in the 1-5-micron range developed by the University of California-Los Angeles Physics and Astronomy Department. Other key elements of the Sofia science instrument suite include the Great (German Receiver for Astronomy at Terahertz frequencies) and Hipo (High-speed Imaging Photometer for Occultations) devices.
Sofia was scheduled to conduct its 110th flight overnight on June 27-28. More than 40 of the flights have been science missions. The aircraft was on the ground during 2012 while the observatory development was largely completed and the cockpit modernized to meet future navigation requirements.