Newswise — On Wednesday, May 26, a telescope mounted in the fuselage of a modified 747 jumbo jet captured the first infrared images for NASA’s newest and largest airborne astronomical observatory. Nearly 10 feet in diameter and weighing the equivalent of two school buses, the 17-ton telescope is NASA’s newest addition to its array of satellite-mounted and ground-based observatories. Designed to operate for the next 20 years, the project is called SOFIA (Stratospheric Observatory for Infrared Astronomy). Luke Keller, an associate professor of physics at Ithaca College, is a co-investigator on the Cornell University–based team of scientists and engineers who designed and built FORCAST, the infrared camera system that produced SOFIA’s first images. A key contributor to designing the optics for FORCAST as well as leading the team that analyzed the data it produced, Keller is available to talk to reporters and editors about the new insights SOFIA will provide on the formation and evolution of the universe.
“When I was a post-doc at Cornell starting in 1999, we expected to use our instrument on SOFIA by 2001,” Keller said. “But the logistics and technical details of modifying the aircraft, making sure sensitive instruments work in turbulent flying conditions, reaching consensus with the various collaborating agencies, and bringing the aircraft into compliance with safety regulations has been a gigantic undertaking. The delays have been disappointing, but we are thrilled to finally be using SOFIA for astronomy. Astronomers and physicists are constantly looking for better ways to view space and learn about our environment beyond Earth’s atmosphere. With SOFIA now in operation, we are going to see the universe in detail never before possible.”
What is infrared astronomy?
“Visible light is only a small part of the electromagnetic spectrum,” Keller said. “In fact, most of the light coming from the universe is not visible to our eyes or to visible-light cameras. If we rely on telescopes that record only visible light, we’ll have a very incomplete picture. But much of the infrared spectrum is obscured by water vapor and carbon dioxide in the Earth’s atmosphere so we need either a spacecraft-based or airborne telescope to completely observe in the infrared. SOFIA gives us that platform.”
What is FORCAST?
Built at Cornell University’s Center for Radiophysics and Space Research under the direction of Cornell professor Terry Herter, FORCAST (Faint Object InfraRed CAmera for the Sofia Telescope) is the first of eight instruments that will be installed on the telescope over the next several years to capture images of celestial phenomena and to measure physical characteristics such as their chemical compositions, temperatures and motion.
What advantages does SOFIA have over ground-based observatories with infrared capabilities?
“The moisture in the Earth’s atmosphere absorbs much of the infrared spectrum and therefore obscures the images of objects outside our atmosphere,” Keller said. “SOFIA cruises at an altitude of 41,000 feet, which puts it above more than 99 percent of the water vapor in the Earth’s atmosphere. Also, SOFIA, unlike observatories on Earth, is not limited to a fixed geographical location.”
What advantages does SOFIA have over infrared satellite-based observatories?“When equipment malfunctions on a satellite, it is often impossible (or very expensive) to repair or to upgrade as technology improves,” Keller said.
“Because SOFIA returns to Earth after every eight-hour flight, repairs and upgrades will be routine without the necessity to launch spacecraft into Earth orbit.”
What do scientists hope to learn from SOFIA?
By offering unprecedented views of light that does not reach telescopes located on the ground, SOFIA promises to offer new discoveries in many areas of current astrophysical investigation, including:• details of the process of star formation in the Milky Way, our home galaxy• dynamic activity surrounding the black hole in the center of the Milky Way galaxy• formation and evolution of planets in star systems beyond our own solar system• the composition and structure of planetary atmospheres• formation and processing of pre-biotic molecules in interstellar space (the building material of future stars and planets)• the role of ultraluminous infrared galaxies in the formation of the early universe.More information is available at Keller’s blog—www.ithaca.edu/frequent_flyer—and at www.sofia.usra.edu and www.nasa.gov/sofia. A gallery showing the aircraft in flight, the interior of the fuselage, and other related images is available, with captions, at http://www.nasa.gov/centers/dryden/multimedia/imagegallery/SOFIA/index.html.
SOFIA FACT SHEET• SOFIA is designed to operate for the next 20 years.• SOFIA will support astronomical observations for about 50 science teams a year, selected from peer-reviewed proposals.• An on-going instrument development program will ensure the facility takes advantage of the most up-to-date technology during its lifetime.• SOFIA flights will typically last eight hours, with the aircraft flying at 41,000 feet (commercial aircraft normally cruise at 35,000 to 38,000 feet).• The door to the telescope cavity will never be opened below 35,000 feet to protect the telescope optics from our atmosphere’s dust, moisture and pollution.• To accommodate the telescope’s reflective mirror, the cavity door, when opened, will create an open space in the fuselage 18 feet long and 13.5 feet wide.• The telescope’s aperture is 2.5 meters (a little over 8 feet) in diameter.• Staffing: flight crew (pilot, co-pilot, flight engineer); science crew (mission director, telescope operator, instrument operator, and at least one astronomer conducting astronomical observations); investigator crew (5 to 10 individuals selected from peer-reviewed proposals).• Because the aircraft can accommodate passengers, an Airborne Astronomy Ambassador Program will be implemented for teachers (K-12), college faculty, and science museum personnel to help them gain first-hand experience with the processes of scientific inquiry.• Since the SOFIA telescope can only point out of the left side of the aircraft, the plane flies from east to west to observe the southern part of the sky and west to east to observe the northern part; flight plans therefore look chaotic since the aircraft has to change direction every time the telescope observes a new object, typically every hour.• Major aerodynamic challenges:o keeping the telescope still in relation to air turbulence and the motion of the aircrafto stabilizing the unbalanced weight distribution caused by placing the heavy, 17-ton telescope at the rear of the fuselageo routing the air flow over the telescope cavity door in the fuselage once the door is openo Keeping the telescope cavity cooled before takeoff to match expected temperatures at the operating altitude and thereby avoid distorting images• SOFIA Managemento Aircraft operations: NASA Dryden Flight Research Center, Edwards, California (eventually operations will also be conducted out of Christchurch, New Zealand, so that objects not observable from the northern hemisphere may be investigated).o Science operations: NASA Ames Research Center and Universities Space Research Associationo Deutches Zentrum für Luft und Raumfahrt (DLR)o Deutsches SOFIA Institut (DSI), Universität Stuttgart, Germany• Cost of 10 years of development and 20 years of operation will come to about $2.98 billion.
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