Earlier today, the American Geophysical Union held its annual meeting in San Francisco, where a team of scientists announced that they had mapped the ionosphere for the first time. The ionosphere, as you know, is the border between earth and space, and the region from which Space Ghost used to transmit his Coast to Coast talk show. The ionosphere can mess with satellites and communications, so measuring it is a big deal. And, it turns out, some UT Dallas guys — Roderick Heelis and Greg Earle — built two of the instruments that made the measurement possible. More details from UT Dallas after the jump:
The ionosphere is the essential border between earth and space. Forecasting disturbances in the ionosphere, which can disrupt or destroy satellite signals, has become increasingly important to our modern society. From the food we eat, to delivering holiday packages, to the safe navigation of our airplanes and boats, almost every aspect of communication and location mapping are dependent on satellite signals shooting smoothly through the ionosphere to a receiver here on Earth. But smooth transmissions depend on conditions in the ionosphere-and that very uncertainty could prove treacherous for vessels that depend on GPS signals for navigation.
Scientists from NASA, the U.S. Air Force and the University of Texas at Dallas are working from data captured from the C/NOFS Satellite, the Communication/Navigation Outage Forecast System (C/NOFS). The satellite was launched on April 16, 2008 on a Pegasus XL rocket aboard Orbital Science Corporation’s L-1011 “Stargazer” jet. Some of the findings revealed by this project:
· a map showing size and shape of the Earth’s ionosphere
· that the ionosphere is up to 100 degrees cooler than previously thought
· that the effective thickness of the ionospheric shell is less than expected
· most disturbances happen after midnight and along the Earth’s magnetic field
· a view of the daily expansion and contraction of the ionosphere around the equator
UT Dallas scientist Roderick Heelis, whose instruments are aboard C/NOFS, said the ionosphere expands during the day, when the upper surface rises, but not as high as the team thought it might. Further, the daily expansion and contraction of the ionosphere has been observed continuously around the equator for the first time. Had sunspot activity not dropped off-with associated cooling of the ionosphere-scientists would not have been able to watch the ionosphere expand and contract. The so-called “quiet time” view of the ionosphere, when sunspot activity is low, allows Heelis and Greg Earle, another UT Dallas physics professor and team member, to study the region of the ionosphere that is hazardous to radio communications. Heelis and Earle built the two instruments aboard C/NOFS:
· The Ion Velocity Meter, which measures the direction and speed of ions as well as their density, temperature and chemical composition
· The Neutral Wind Meter, which measures the speed and direction of the neutral atoms and molecules in the near vacuum of space.
The 20-pound package of sensors and electronic equipment was fabricated in Heelis’ UT Dallas laboratory with Earle’s assistance and in collaboration with Paul Mahaffey of NASA’s Goddard Space Flight Center.
“Years ago, my basic question began as, ‘How does our space environment interact with the sun?'” Heelis said. “I was intellectually curious about that. But now, as we become more dependent on assets in space, answering that question has real importance to everyday commerce, to military and commercial communications and navigation. NASA and the Air Force want to know the answers, and it’s enlightening to see major agencies working with us at UT Dallas to share resources and work on these problems together.”
