GPS/GIS mapping helps narrow search for shuttle debris
- — 06 February, 2003 11:13
Using Global Positioning System-derived geo-location data to define the debris field from the breakup of the shuttle Columbia, researchers and undergraduates from Stephen F. Austin University in Nacogdoches, Texas have helped narrow search patterns in east Texas, where thousands of pieces of the spacecraft have been located.
Darrel McDonald, director of the Humanities Undergraduate Environmental Sciences (HUES) geographic information system (GIS) program at the school said the data from the nearly 1,000 pieces of shuttle debris already located has helped emergency workers better focus on the areas they need to search along the vehicle's debris path.
The shuttle debris data collection effort -- staffed by teams from both the HUES GIS program and the university's Forest Resources Institute -- has helped produce digital maps that provide a retrogressive pattern of debris, McDonald said. "This has improved the search effort, but has not totally solved the problem" of finding debris that could explain what happened to the Columbia upon re-entry Saturday morning, he said.
The shuttle crashed just after 9 a.m. EST, killing all seven crew members on board and raining debris in heavily wooded areas of eastern Texas and neighboring Louisiana.
The university is now fielding between 60 and 70 teams, with a total of between 150 and 200 people working to locate shuttle debris, McDonald said. The field crews use professional grade Global Positioning System (GPS) receivers from Trimble Navigation Ltd. in Sunnyvale, Calif., to locate particular pieces of debris.
That location information is stored in an onboard datalogger, and when field workers return to the lab it is run through postprocessing software to enhance the accuracy of the data, McDonald said.
While raw data received from the 24-satellite GPS array provides location accuracies to within 100 feet or better, the Trimble postprocessing software improves that accuracy to around three feet, McDonald said. That finely-tuned data is then fed into ArcInfo GIS software from Environmental Systems Research Institute Inc. (ESRI), in Redlands, Calif. The ESRI software plots the data points on a digital map overlaid with information about the locations of roads and topographic features. That map is enhanced by satellite photographs from Spot Image Corp.
McDonald said the Stephen F. Austin GIS lab then provides the maps -- updated daily as field workers input more data -- to local, state and federal agencies, including NASA and the Federal Emergency Management Agency (FEMA). He said FEMA is working to install a high-speed data line between the university's GIS labs and FEMA's command post in Lufkin, Texas. So far, he said, the GIS labs have provided mainly paper maps to federal, state and local agencies.
Mike Phoenix, manager for international higher education reprograms at ESRI, said the shuttle debris mapping project taps into the essential power of GIS systems: the ability to visualize data and see patterns. He said that advancements in both GPS and GIS technologies have provided NASA and emergency agencies with tools that weren't available 17 years ago in the aftermath of the explosion of the Challenger shuttle.
