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NASA's airborne telescope will always be state of the art

Imagine pointing a telescope out of your car window and scouring the heavens for new clues about the origins of the universe while cruising down the highway. That’s what SOFIA – NASA’s and the German Aerospace Center’s Stratospheric Observatory for Infrared Astronomy - does only it’s mounted in the back of a Boeing-747 flying at 500 miles per hour at 40,000 feet.

[SOFIA, the 'Stratospheric Observatory for Infrared Astronomy,' stopped at Joint Base Andrews near Camp Springs, Md., Sept. 22 on it's way back from Germany to its home at NASA's Dryden Aircraft Operations Facility in California. SOFIA is the world's largest airborne observatory.]

Link[The infrared telescope on board SOFIA is at the rear of the Boeing-747.The lens mirror itself is behind the white wall. The silver equipment at left is one of several interchangeable instruments that can be attached to the telescope.]

(Scroll down for more photos from the SOFIA tour...)

Scientists studying the universe know there is much more to see besides the visible light seen by human eyes. That’s where this infrared telescope comes in. Looking for infrared radiation coming in from the cosmos isn’t as simple as pointing a telescope up to the heavens though, because water vapor in the Earth’s atmosphere absorbs mid- and long-range infrared radiation before it reaches the ground.

Because water vapor is heavier than other gasses in Earth’s atmosphere, like oxygen and nitrogen, flying at 40,000 feet allows SOFIA to fly above about 99 percent of the water vapor in the atmosphere. The telescope has a clear view of the entire range of infrared radiation coming from space.

[NASA Astronaut Leland Melvin talks about how NASA programs like SOFIA can help inspire a new generation of students to study the STEM subjects of science, technology, engineering and mathematics.]

[Mary Blessing, an astronomy teacher at Herndon (Va.) High School, talks about her flight on board SOFIA which she called the "highlight" of her career. Blessing flew as a part of the Airborne Astronomy Ambassadors program which gives educators a chance to work alongside scientists doing astronomy research, an experience which they may then share with their students.]

Satellite-based telescopes in orbit around the Earth are also able to see this infrared radiation, but they cannot be easily modified (as tinkering with satellites is difficult) and their instruments are only state-of-the-art for a very short time. SOFIA, however, “comes home every night so we can maintain it and even better - we can upgrade it,” said NASA SOFIA program scientist Paul Hertz.

Hertz spoke about the science behind SOFIA during a Sept. 22 tour of the aircraft at Joint Base Andrews in Maryland. “SOFIA will always stay on the cutting edge of astronomy technology,” Hertz said, because a new instrument can be attached to the telescope before any flight.

[SOFIA is parked outside a hanger at Joint Base Andrews in Maryland on Sept. 22, 2011.]

[SOFIA stands for 'Stratospheric Observatory for Infrared Astronomy' and is a joint project between NASA and the German Aerospace Center.]

The joint project between NASA and the German Aerospace Center will help scientists better understand the formation of stars and planets, the history of the Solar System, the evolution of galaxies and the role of the black hole at the center of the Milky Way among many other things said NASA Deputy Administrator Lori Garver during a talk before the tour.

“It will help us zoom in close on some of the most fundamental questions of the universe: Where did we come from, how was our solar system formed and what else is out there?” Garver said. “It is fitting that ‘sofia’ means wisdom in Greek,” she added.

In fact, SOFIA was working during its flight across the Atlantic. The 2.5 meter diameter lens mirror was pointed at the center of our galaxy, perhaps taking data about the black hole there. What, exactly, SOFIA was looking at on that flight, though, remains a mystery - for the time being. Data collected by SOFIA is proprietary information available only to the mission’s scientists for six months to a year before it is released to the public for anyone to examine and use.

[Scientists sitting at these and similar consoles can monitor the data SOFIA collects as a flight progresses.]

[The telescope is at the rear of the airplane with the lens mirror itself outside the pressurized part of the vessel. Inside, at left, everything in blue is a permanent part of the telescope while the silver attachment is one of several interchangeable instruments. Because new instruments can be added at any time, SOFIA will always be a state-of-the-art infrared telescope.]

[This NASA image from August 2010 shows SOFIA in flight with the telescope door open. Photo credit: NASA]

Stefan Heyminck, a project engineer for the telescope who came from the Max Planck Institute for Radio Astronomy in Germany, said the coolest thing so far about seeing SOFIA in flight was watching how the telescope performed during turbulence. Though they were bouncing around in their seats, Heyminck said, he was still seeing perfectly clear data on his laptop.

The whole telescope assembly sits on a ball bearing that’s swimming on an oil film and when balanced with counter weights, it can be moved by just the touch of a finger. This allows it to move independent of the aircraft. “[When ]the aircraft is bouncing around, the telescope doesn’t follow,” Heyminck said. Motors compensate for the aircraft movement to keep the telescope steady even during heavy turbulence.

Though SOFIA has flown some science missions already, including one that returned new data about stars in the constellation Orion, it is still under development. The airborne observatory should be fully operational by 2014 and is expected to have at least a 20-year lifespan.

[NASA SOFIA program scientist Paul Hertz, far left, stands with NASA Astronaut Leland Melvin, NASA Deputy Administrator Lori Garver and high school astronomy teacher Mary Blessing in front of SOFIA's tail.]

[A SOFIA pilot, at right in a tan jumpsuit, answers questions about the aircraft posed by children from military families who are touring SOFIA as part of the White House Joining Forces initiative. The initiative, headed by Michelle Obama and Jill Biden, works to give back to service members and their families the "opportunities and support they have earned."]


  1. The SOFIA telescope uses a 2.5m mirror, not a 2.5m lens. Flying IR telescopes are pretty cool!

  2. I'm no physics person (medical trained) but surely the vibrations alone on the aircraft would render readings from such an instrument pretty useless...

  3. @steven - Thank you for catching that mistake! Where was my head yesterday? It's been fixed. --Echo

  4. @chipchip1971 –

    You bring up a good point. Fortunately, the telescope was designed with this in mind.

    The telescope itself balances on a ball bearing, which, in turn, is swimming on an oil film. That helps to overcome the vibrations from the aircraft. Furthermore, each time an instrument is attached to a telescope, it is balanced with counter-weights such that “the whole telescope can be moved with a finger,” according to Brent Cobleigh, the NASA platform project manager who is in charge of the airplane and the observatory.

    The telescope is also independent of the airplane and motors compensate to keep it stable so that when the plane vibrates or moves around during turbulence, the telescope is still steady. Stefan Heyminck, a project engineer who works on the instrument side of the telescope, said that the angular resolution they have demonstrated so far is roughly one inch over three miles. He also spoke anecdotally about a recent flight when he was strapped to his seat during heavy turbulence and was still getting perfectly clear data.

    If you're interested in learning more, there are a lot of great details about the telescope assembly in this article: The ‘Hurricane and earthquake’ section addresses vibrations specifically.



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