Thursday, February 25, 2010
Space Science at the Top of the World
By John Ohab
Dr. Todd Pederson, Air Force scientist at the High-Frequency Active Auroral Research Program (HAARP), is back to explain how his cutting-edge research in Greenland is helping satellites and radars better protect our military. Special thanks to Michael Kleiman, 377th Air Base Wing, for co-producing this series.
Dr. Todd Pedersen is a space physicist serving with the Air Force Research Laboratory, Space Vehicles Directorate’s, Battlespace Environment Division, Hanscom Air Force Base, Mass. He got his start as an experimenter early in life playing with magnets, wires, and other fun stuff salvaged from old radios, motors, and cars.
It’s August, so during lunch break, I take a short walk down to the beach. Only this is not your ordinary late summer beach.
Sure, it has sand, and some seaweed, but no Frisbees, no volleyball, and no sunbathers. It looks more like a demolition derby after everyone has gone home. But instead of crushed cars strewn about on the sand, the beach is littered with car-sized chunks of ice. Baby icebergs are stranded by the tide. Their parents are out in the bay, towering high enough that the helicopter had to dodge them as it ducked below the fog bank to bring us in a few days before.
I’m in Qaanaaq, a thriving community of several hundred families in northwest Greenland, located nearly 2,500 miles due north of my office in the Boston suburbs. After strolling like Alice in Wonderland through the oversized ice cubes, we head back to the little hut that houses our instruments. That is why we are here, after all. The beach may be empty, but the sky above us is a busy place, filled with satellites and radio waves.
Beyond the bay and the large ice-covered peninsula on its far side is Thule Air Base, home to a huge, pyramid-shaped radar that scans these skies, tracking satellites, and looking out for missiles we all hope are never launched. The satellites and radars are only part of the story. A hundred miles up — in fact, a hundred miles up from anywhere on earth — is the ionosphere, a layer of plasma created when sunlight hits the atmosphere.
Back in Boston, the ionosphere is smooth most of the time, like a good waterskiing pond. It acts like a nice, flat piece of glass in a window or mirror, letting radio waves such as global positioning system signals or radar pulses through or reflecting them, depending on their frequency. Up here near the magnetic pole, however, the ionosphere gets pushed around by the solar wind coming in from the sun, and breaks up into drifting chunks like billows of smoke from a smokestack. This ionosphere doesn’t make very good windows or mirrors.
I am here in Qaanaaq to install equipment — a radar that bounces pulses off the ionosphere called an “ionosonde,” and a low-light imager that captures the faint glow from the turbulent plasma — that lets us monitor these disturbances. If we scientists can understand and maybe even forecast how the ionosphere twists itself into these disruptive tangles, we can help the satellites and radars see through the mess better to protect our homeland and help our troops, ships, and planes find their destinations wherever they are called to serve.