Stratospheric Observatory for Infrared Astronomy (SOFIA): Infrared Sensor Development and Science Capabilities

The Stratospheric Observatory for Infrared Astronomy (SOFIA) is a unique airborne observatory designed to operate in the lower stratosphere to altitudes as high as 45,000 feet and above 99.8% of Earth’s infrared-obscuring atmospheric water vapor. SOFIA’s capabilities enable science that will complement and extend past, present and future infrared telescopes in wavelength range, angular and spectral resolution, and observing flexibility. The joint U.S. and German SOFIA project to develop and operate the 2.5‐meter telescope aboard a Boeing 747‐SP is now in its final stages of development. Flying in the stratosphere where the average atmospheric transmission is 80%, SOFIA allows observations throughout the infrared and submillimeter region of the spectrum. The SOFIA instrument complement includes broadband imagers, moderate resolution spectrographs capable of resolving broad spectral features due to dust and large molecules, and high resolution spectrometers suitable for kinematic studies of molecular and atomic gas lines. A great strength of SOFIA is the enormous breadth of its capabilities and the flexibility with which those capabilities can be modified and improved to take advantage of advances in infrared technology. This paper and presentation will highlight the following points: A 2.5-meter effective-diameter optical-quality telescope for diffraction-limited imaging beyond 25 μm, giving the sharpest view of the sky provided by any current or developmental IR telescope operating in the 30-60 μm region; Wavelength coverage from 0.3 μm to 1.6 mm and high resolution spectroscopy (R to 10) at wavelengths between 5 and 150 μm; An 8 arcmin FOV allowing use of very large detector arrays; Ready observer access to science instruments which can be repaired in flight and changed between flights; A low-risk ability to incorporate science-enabling instrument technologies and to create a whole new observatory several times during the lifetime of the facility; Opportunity for continuous training of instrumentalists to develop and test the next generation of instrumentation for both suborbital and space applications; Mobility, which allows access to the entire sky and a vastly increased number of stellar occultation events; Unique opportunities for educators and journalists to participate first-hand in exciting astronomical observations. This paper also describes the eight first generation science instruments and plans for future instrument development. The midand far-IR wavelength regions are key to studying the dusty universe, typically hidden at shorter wavelengths. SOFIA science emphasizes the observatory’s unique role to help understand star and planet formation, the interstellar medium, nearby galaxies and the galactic center, and our own solar system and other planetary systems. SOFIA’s capabilities will enable a wide range of science investigations over its 20-year operational lifetime. SOFIA’s first light flight is expected to occur in 2010 followed by a series of early science flights and instrument commissioning flights. SOFIA expects to declare limited operational capability in 2012, and full operational capability in 2014.