Sarah experiences science on SOFIA

Posted by Sarah Scoles
on Friday, June 21, 2013

My previous blog post was an incomplete record of the evening (or, more accurately, the morning). I wrote it just before my Tuesday/Wednesday flight on the Stratospheric Observatory for Infrared Astronomy (SOFIA) ended — just before I was allowed to sit in the 747's cockpit, where I had a headset but kept my mouth shut and learned exactly how much back and forth happens between an aircraft and ground control. Seeing sunrise — and rapidly approaching mountaintops — through the pilot's windows was an experience as special as seeing astronomers use a telescope with which they had flown more than 10,000 feet higher than commercial planes.

A plaque at a lookout above Antelope Valley. // all photos by Sarah Scoles
Experimental aeronautics like SOFIA are right at home in Antelope Valley, California, which hosts the NASA Dryden Aircraft Operations Facility (DAOF), Edwards Air Force Base, Lockheed Martin, and other high-speed, high-stakes aircraft facilities. This part of the Mojave High Desert has large, flat, empty stretches of land that (at least at one time) weren't too pricey. Aero-agencies and -companies took advantage and have been reaping the benefits ever since.

My grandparents actually lived here in Palmdale, where the DAOF (pronounced “day off,” by the way) is, when my mother was born. Out of deference to her will, I won't provide the year, but at that time, my grandfather worked with these flight facilities. I was able to go to their old house, take a picture, and slink away before anyone thought I was creepy.

The scaled and physically accurate model of the tube connecting telescope and photon detector.
And after that personal detour, my fellow Airborne Astronomy Ambassadors — Anne Smith of Green Bank, West Virginia, and John Clark of Deltona, Florida — went on a tour of DAOF's lab facilities. Here, they house a mock-up of the tube that connects the telescope  — in its unpressurized, sub-freezing environment — to the light detector  — in its pressurized, cold-but-not-subfreezing environment with SOFIA's passengers. The SOFIA team can test detectors by mounting them in the lab and shining a “big flashlight,” a technical and only slightly inaccurate term, that simulates a source in space. As I'm sure you can imagine, hauling a heavy instrument to the deck of a 747 is no small task, so it's best only to do it when you're sure the detector is all green lights.

The mirror coating vault.
The mirror coating facility is also on the ground. SOFIA's mirror occasionally needs touch-ups, and the team can haul it into the hangar, use a crane to lift it into a tank that can melt its current gloss of aluminum, and re-coat it to a specified thickness and smoothness.

The plane holding that smooth mirror took off on time Thursday night, so we actually had a view from our cruising altitude before it became dark, and we were able to witness a sunset across the barren expanses of canyons and dry western mountains. It was clear that we had flown very high, as strata were visible in the atmosphere and Earth's surface looked vaguely curved.

Looking out the window with me were two videographers from NASA TV who had stowed away on the flight. Watch NASA TV constantly from tomorrow until whenever you see The SOFIA Show, for which all Ambassadors were interviewed.

This is an observatory that deserves time in the spotlight, given that for every one infrared photon coming from an astronomical “object of interest,” 100,000 photons of background infrared radiation are trying to drown it out.

Surprisingly, observing during the day wouldn't be that much more difficult, in terms of the brightness of the background. But because the mirror is coated in metal and is meant to focus light, it would focus solar radiation and heat up the apparatus to the point of catastrophe. No thanks. I'd prefer to stay up all night, even if that means I haven't known what day of the week it was since Monday.

The view at approximately 42,000 feet, on ascent.
Because Tuesday's tests were successful, the Thurday/Friday flight was a science mission. The theme of the evening (and of infrared astronomy in general) was “dust.” The telescope operators and instrument scientists commanded SOFIA to complete four projects that scientists around the world had proposed. After a rigorous peer-review process, these proposals were deemed worthy of flying high, but because SOFIA is a specialized telescope with many parameters and acronyms known only to those in the know (or those with the explanatory binder), the astronomers themselves don't do the observing. They just get some nicely packaged data after it's stripped from the onboard 1-terabyte disk.

Tonight, SOFIA observed:

  • The dust from the stellar winds shot from giant stars
  • Polycyclic aromatic hydrocarbons, organic molecules that reside in star-forming regions; by characterizing how these molecules look in well-known regions of our galaxy, scientists can search other galaxies for the same signatures
  • Stars forming in clusters; other infrared telescopes haven't had high-enough resolution to separate the individual baby stars in clusters
  • Jets shooting out of high-mass almost-stars; In utero, these “young stellar objects” have hot (2,000 kelvin) and cold (200 kelvin) hydrogen that both emit infrared waves that SOFIA can detect

Pay no attention to the man behind the camera.
Tonight/this morning concludes my hands-on experience with this flying observatory, and I'm glad I was able to experience stratospheric sunset and the scientific process at work — from tests, to problems, to solutions, to pretty pictures and spectral lines. I've met engineers, mechanics, astronomers, physicists, pilots, safety technicians, mission directors, and communicators. It's been fascinating to hear how they have come to careers that take them to the stratosphere and the circuitous paths that led them to astronomy. When you slice an opening in a huge jet and say, “Let's look at stuff millions or billions of light-years away while traveling 500 mph,” it makes sense that you would unite different types of people who all want to add knowledge to the world and have a little fun — but no peanuts or beverage service — while doing so.

And now, at 5:00 a.m., we all are about to begin our descent into Palmdale. Goodnight?

SOFIA being a fully functional telescope.
Related blogs:

Sarah experiences a SOFIA calibration flight

Sarah preps for flights on SOFIA

Sarah takes a trip on SOFIA, the flying infrared observatory

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