Guest Post: Daniel Angerhausen and the Flying Observatory

by Mary Martialay on April 29, 2013

Daniel Angerhausen with SOFIA

Daniel Angerhausen with SOFIA

(Later this week, Daniel Angerhausen, a postdoctoral fellow in the lab of Jon Morse, Rensselaer Polytechnic Institute professor of physics and associate vice president for research for physical sciences and engineering, will be flying aboard the airborne telescope SOFIA. Angerhausen, a native of Uerdingen, Germany [about 30 minutes from Cologne], sent us this excellent post about the flight and his research. Enjoy!)

My name is Daniel Angerhausen, I’m a postdoc in the Department of Physics, Applied Physics, and Astronomy at RPI, and on Thursday I will fulfill one of my biggest dreams: I will be on board the flying observatory SOFIA to observe a planet in a another solar system.

The Stratospheric Observatory for Infrared Astronomy  (SOFIA), a joint project of NASA and the German Aerospace Center (DLR),  is basically a 2.5 meter-wide telescope aboard a Boeing 747-SP airplane (you can see it in action in this video). If you ever looked out of a plane window,  you may have noticed that you are most of the time above the clouds and, in short, that is the reason SOFIA was built: flying at altitudes of about  41,000 feet enables the instruments  on SOFIA to collect light that is absorbed by the atmosphere before reaching telescopes on the ground and even on high mountains.

I did my diploma studies at the University of Cologne, where the Astronomy Department was building parts of an instrument for SOFIA. From the first time I heard of SOFIA I was fascinated by the combination of astronomical science and airborne engineering, and SOFIA actually was one of the reasons I choose astrophysics as my major. Ten years ago a German magazine interviewed me, and the last thing I said in the article was (translated): “My institute helps building a flying observatory and one of my biggest dreams would be to fly with SOFIA one day.”

After my time in Cologne I started my doctoral studies at Caltech/NASA-JPL and also the German SOFIA Institute, specializing on the characterization of so called extrasolar planets, planets that orbit stars outside of our solar system.  Some of these exoplanets transit (pass) in front of their host star,  similar to the Venus transit of the Sun that we were able to observe last summer. During this transit the star’s light is blocked by the planet and a tiny decrease in the brightness of the star is observable (here’s a cool video explaining how it works). From these brightness variations, or light-curves as we call them, we can find out many characteristics of these planets. In our observation we are trying to detect signatures of water in the planetary atmosphere of an exoplanet called HD189733b. We need SOFIA flying up in the stratosphere for these observations because the air humidity alone would blocks these water signatures from observation lower in the Earth atmosphere.

For my doctoral thesis, I found out that these observations are possible with SOFIA and in early 2012 NASA issued the first call for SOFIA proposals (astronomers prepare a “proposal” by way of applying for time to use a particular observatory). The proposal that I worked on with colleagues from NASA Goddard space flight center was awarded the observation time on SOFIA. Unfortunately (but lucky for me), due to sequestration, these NASA colleagues were not able to go on the flight. Because they weren’t able to go, I was offered the super exciting opportunity to fly just a week ago.

I did not hesitate a second to accept: I’ve visited SOFIA a couple of times in the hangar but finally flying through the stratosphere on a scientific plane with a huge NASA logo on its side, exploring alien planets is probably the closet I will get to being an astronaut in my life – a Stratospheronaut  … maybe.

Like I said, I’ll be flying Thursday, May 2 (and you can follow my flight on this flight tracking page). Keep your fingers crossed for my observations – I will keep you posted on the flight itself next week and the results in some month.