Darlene Mendoza’s cheek shows a dark square where ice has cooled her skin during a demonstration of infrared imaging.

Put a 45,000-pound observatory with an infrared telescope the size of Hubble in the back of a sport model 747SP and on a clear day, you can see forever. The best part is, at 41,000 feet, it’s always a clear day. That’s the beauty of NASA’s new Stratospheric Observatory for Infrared Astronomy (SOFIA). It can fly above 99 percent of the Earth’s atmospheric water vapor, the enemy of infrared observation. Still in its test and integration program, SOFIA promises to take heat-based infrared astronomy to new heights, above ground-based observatories.

Members of the SOFIA team have a display in the NASA exhibit building featuring an infrared video camera that depicts hot and cold spots on a monitor. Kids like to use ice cubes to paint mustaches and lipstick on their faces, says SOFIA exhibitor Darlene Mendoza.

SOFIA astronomer Dana Backman came to AirVenture from NASA’s Ames Research Center near San Jose, California. Dana says infrared astronomy "shows you a completely different view of the universe." Dana is excited about SOFIA’s potential to reveal information about the origin of stars and planets.

As stars form, they produce more infrared energy than visible light. SOFIA can image this formation process. Astronomers can compare visible-light images from other telescopes with infrared pictures made by SOFIA. "If you put them together, they tell you more than they would independently," he explains.

Some clever mathematics comes into play for astronomers. How can they tell if an infrared source is very weak, or very distant, since distance diminishes infrared intensity? For example, careful observations over time, as the Earth moves, can permit parallax measurements, to help determine the placement of stars in the cosmos, so astronomers can weigh dimness versus distance.

Dana explains another phenomenon that SOFIA can penetrate: visible light emitted by very distant stars a long time ago can shift into the infrared spectrum over time due to the expanding universe. This expansion stretches the wavelength of the light en route to us.

Dana enjoys boiling complex astronomy down for the rest of us. And he doesn’t wear a pocket protector. He looks forward to using SOFIA to learn more about star and planet formation, as well as a means of increasing humanity’s sum total of knowledge.

"All gold comes from exploding stars," he says, because that is the only process hot enough to create gold. The rarity of exploding stars depositing material on Earth is what makes gold scarce, and hence valued.

The SOFIA 747SP is a veteran of Pan American Airways and United Airlines. In 1977, Pan Am asked Charles Lindbergh’s widow, Anne Morrow Lindbergh, to christen this airplane Clipper Lindbergh. On May 21 this year, the 80th anniversary of Charles Lindbergh’s solo trans-Atlantic flight, grandson Erik Lindbergh rededicated SOFIA as Clipper Lindbergh for NASA.

The creation of SOFIA is a collaboration between NASA and DLR, the German space agency. Germany supplied the telescope and its attendant equipment, and German astronomers will participate in its use. The scientific use of SOFIA is being planned by the Universities Space Research Association (USRA) and Germany’s Deutsches SOFIA Institut (DSI) under the leadership of the SOFIA science project at NASA’s Ames Research Center.

SOFIA is in its flight-test program at NASA’s Dryden Flight Research Center on Edwards Air Force Base in California. The special 747SP has a 16-foot door in the aft fuselage to give the telescope free access at altitude.

As the flight-test program unfolds, the telescope’s systems will be integrated simultaneously. The telescope cavity must be pre-cooled before opening at altitude to keep the telescope optics from fogging over or being damaged by a radical drop in temperature. The telescope must be shock-mounted to damp out airframe vibrations, and the telescope’s sophisticated tracking system must work with the 747’s autopilot to enable SOFIA to focus on a scene for several hours at a time for infrared exposures.

NASA officials are optimistic that "first light"—astronomy code for the first time SOFIA will make an image for scientific purposes—will occur in 2009. Dana calls SOFIA "a brilliant compromise" between ground-based telescopes of limited usefulness and satellite telescopes that cost a fortune and are very difficult, at best, to service or modify. The 747 that lands at the end of a sortie has found the "sweet spot" for infrared astronomy, Dana says.