NASA'S SOFIA(Stratospheric Observatory for Infrared Astronomy)

 Stratospheric Observatory for Infrared Astronomy -SOFIA

he Flying Observatory 

SOFIA soars over the snow-covered Sierra Nevada mountains with its telescope door open during a test flight. SOFIA is a modified Boeing 747SP aircraft.

Credits: NASA/Jim Ross

SOFIA, the Stratospheric Observatory for Infrared Astronomy, is a Boeing 747SP aircraft modified to carry a 2.7-meter (106-inch) reflecting telescope (with an effective diameter of 2.5 meters or 100 inches). Flying into the stratosphere at 38,000-45,000 feet puts SOFIA above 99 percent of Earth’s infrared-blocking atmosphere, allowing astronomers to study the solar system and beyond in ways that are not possible with ground-based telescopes. SOFIA is made possible through a partnership between NASA and the German Space Agency at DLR.

The observatory’s mobility allows researchers to observe from almost anywhere in the world, and enables studies of transient events that often take place over oceans where there are no telescopes. For example, astronomers on SOFIA studied eclipse-like events of Pluto, Saturn’s moon Titan, and Kuiper Belt Object MU69, the next flyby target for NASA’s New Horizons spacecraft, to study the objects’ atmospheres and surroundings.

SOFIA and the Infrared Universe

SOFIA is designed to observe the infrared universe. Many objects in space emit almost all their energy at infrared wavelengths and are often invisible when observed with visible light. In other cases, celestial clouds of gas and dust block the light emitted by more distant objects, but infrared energy pierces through these clouds. In both cases, the only way to learn about these objects is to study the infrared light they emit.

Visible (left) and infrared (right) images of the Horsehead Nebula. The dust that forms the Horsehead blocks visible light but glows brightly in the infrared. The infrared image, taken by SOFIA’s upGREAT instrument, shows carbon monoxide molecules sheltered in the dense nebula (red area) and carbon atoms and ions that have been affected by the radiation from nearby stars (green area).

Credits: Left: Dylan O’Donnell; Right: NASA/SOFIA/J. Bally et. al

During 10-hour, overnight flights, SOFIA observes the solar system and beyond at mid- and far-infrared wavelengths gathering data to study:

• Star birth and death
• ​Formation of new solar systems 
• Identification of complex molecules in space
• Planets, comets and asteroids in our solar system
• Nebulas and galaxies
• Celestial magnetic fields
• Black holes at the center of galaxies

SOFIA's telescope instruments — cameras, spectrometers, and polarimeters — operate in the near-, mid- and far-infrared wavelengths, each suited to studying a particular phenomena. Spectrometers spread light into its component colors, in the same way that a prism spreads visible light into a rainbow, to reveal the chemical fingerprints of celestial molecules and atoms. Polarimeters are sensitive to the effect magnetic fields have on dust in and around celestial objects, allowing astronomers to learn how magnetic fields affect the birth of stars and other objects.

Unlike space-based telescopes, SOFIA lands after each flight, so its instruments can be exchanged, serviced or upgraded to harness new technologies. Because these new instruments can be tested and adjusted, SOFIA can explore new frontiers in the solar system and beyond and serve as a testbed for technology that may one day fly in space.