My Night With SOFIA

by Mary Martialay on November 14, 2013

Daniel Angerhausen celebrates his flight aboard SOFIA

(We’ve been following Daniel Angerhausen, a postdoctoral fellow in the Department of Physics, Applied Physics, and Astronomy, in his quest to conduct research aboard NASA’s flying observatory, SOFIA. From anticipation in April, to disappointment in May, we are pleased to at last report success and joy. Congratulations Daniel!)

“So I spent the night at 42,000 feet on a billion dollar NASA aircraft observing an alien world 63 light-years away. How was your night?” — Tweet from Daniel the morning after his very first flight on the Stratospheric Observatory for Infrared Astronomy (SOFIA).

I finally did it: I flew on SOFIA — and it was truly amazing.

Earlier this year, I wrote about my research through the Department of Physics, Applied Physics, and Astronomy at RPI, observing extra-solar planets with airborne NASA/DLR observatory SOFIA. At the time, I was looking forward to a scheduled flight on SOFIA, but in my last post, I explained how my flight was derailed by a technical difficulty with the plane. And then I got a back-up date!

Just like last time, things did not look good in the beginning. During my first layover on the way to NASA Dryden Aircraft Operations Facility in Palmdale, Calif., I got a disconcerting email saying that one of the science instruments had problems with its liquid helium cooling mechanism. Also, the looming government shutdown was jeopardizing the planned missions.

At least my last-minute clearance to access the NASA facility worked out after some phone calls, and I was able to attend a so called “line ops” observation the following night. During line ops the SOFIA plane is pulled out of the hanger and put out on the airfield. Then the “garage door” that covers the telescope cavity is opened and SOFIA basically used like a ground-based telescope.

The observations made during line ops usually do not have much scientific use, but are of great value to characterize and calibrate the telescope and the instruments. The procedures for these test observations are pretty similar to an actual flight, the only difference being that the plane stays on ground — so it was also a great exercise for me to get ready for my first flight … scheduled for the very next day.

On Sept 26, at 6:43 p.m. Pacific Daylight Time, I had my very first take off aboard SOFIA. The 6-hour 11-minute flight felt much shorter because everything was so exciting and new to me. During the flight we spent one hour of observation time on HD 189733b, ‘my’ object of interest: a star with a transiting hot Jupiter-like planet.  We needed these tests to calibrate our instruments and to find the best setup for the upcoming observation of an actual transit three days later. “We” in this case were the team of 25-30 people on the plane — pilots, engineers, scientists, telescope and instrument operators (one of them, by the way, RPI alumni Sachindev Shenoy, who now works for SOFIA Universities Space Research Association at NASA Ames).

On the second flight, I got a special surprise: the pilots offered one free seat in the cockpit for take-off, and I got it! We tookd off at 8:56 p.m. on Sept. 30 – literally four minutes before the government shutdown took effect. After ourflight, SOFIA stayed on the ground until the shutdown ended. On this second flight we conducted the very first observations of an extrasolar planet from SOFIA. I brought my little timelapse camera on board and took a video of our mission.

In the video (above), you’ll see that the telescope is on the other side of the blue bearing that you can see in the video, in a cavity open to the outside. You will also see the science instruments (in this case HIPO and FLITECAM) and some counterweights. The telescope is basically swimming on a thin oil film in that bearing and inertia is keeping it stable against the plane’s vibrations. So when you see it “move” in the video it is actually stable with regard to the stars and just compensating for the aircraft’s movement and turbulences.

I am very excited about the data we got on this mission. Despite some technical difficulties we already learned a lot about these observations and the instruments we used. Some of the raw data shows a quality that we usually only can expect from space-based satellite telescopes like the Hubble or Spitzer space telescopes.

I worked on making this flight happen for more than five years, there were lots of obstacles on the way, and I am very happy and really thankful that it finally worked out.

However, this is just the beginning: there are still lots of things to learn from a more detailed analysis of the data. I cannot wait to get my hands on it in order to prepare for (hopefully plenty) upcoming exoplanet observations with SOFIA!