The Yukon Delta as seen on Sept. 22, 2002. (NASA's Goddard Space Flight…)
At 10:02 a.m. Monday, if all goes as planned at Vandenberg Air Force Base, the latest generation Earth-observation satellite, Landsat Data Continuity Mission, a.k.a. Landsat 8, will get a boost into space atop an Atlas 5 rocket. Since 1972, seven satellites have documented Earth's continents and coastlines in images of telling and often astonishing detail. Forty years of Landsat data, what the government calls a "visible, long-term record of natural and human-induced changes on the global landscape," is archived and available online, free for anyone to use.
And it does get used. Water managers in California check Landsat data to help manage our share of that increasingly rare resource, right down to figuring out how to irrigate individual vineyards in the San Joaquin Valley. Wetlands researchers used the images to measure how much of the Gulf Coast Hurricane Katrina swallowed up. The data have tracked Amazon deforestation and, some say, have helped to slow it down.
These images aren't meant to be pretty pictures -- though many of them are. They don't set out to capture big moments and breaking news -- though they often do. They are, instead, a consistent accumulation of wide swaths of information over time, recording the surface of the whole Earth with instruments that see far beyond the human eye (in the infrared spectrum, for example) and the human point of view.
When Landsat had its 40th anniversary in July, NASA and the U.S. Geological Survey combed the image archives for 10 of the most historically significant pictures, and they asked the public to vote on the top five of the photo collection called "Earth as Art." (Among the former -- images of the Kuwait oil fires as Saddam Hussein's troops sabotaged oil wells and retreated during the first Gulf War. Among the latter -- the Yukon River delta in Alaska and sand "seas" in the Sahara. ) These "best of" collections are revealing – EROS, the USGS Earth Resources Observation and Science Center, maintains online galleries of Landsat's greatest hits and posts an "Image of the Week" as well -- but the exercise is a little like judging the great libraries of the world by listing the Top 10 fiction titles in the card catalog: The whole isn't just greater than the sum of its parts, it's in a different league.
Landsat 8 is set to keep the data coming and the archive up to date, courtesy of the U.S. taxpayers. You can watch your investment get off the ground live Monday -- NASA TV starts its coverage at 7:15 a.m. and there's a public viewing area in Lompoc. If the conditions are right, you might even be able to catch a glimpse from your front porch.
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