Dec 18 2001
From The Space Library
NASA officially ended the operation of spacecraft Deep Space 1 when engineers at NASA’s JPL sent a signal to the spacecraft to shut down its engine and cease communications with Earth. NASA had launched Deep Space 1 in October 1998, to test 12 technologies for use in future spacecraft. Although NASA had planned for the spacecraft’s mission to conclude in September 1999, NASA had continued operating Deep Space 1 for more than two additional years with results that were highly beneficial and sometimes unexpected. Most notably, during a close flyby of the Comet Borrelly on 25 September 2001, Deep Space 1 had provided the most detailed pictures ever taken of a comet. In addition, experts stated that, at a cost of approximately US$160 million, the spacecraft’s mission had been the least expensive interplanetary mission ever conducted by the United States. (Warren E. Leary, “Deep Space 1 Ends Mission, but Triumphs Are Clear,” New York Times, 19 December 2001.)
Researchers published findings from an unprecedented analysis of NASA-produced satellite data of carbon absorption by northern hemisphere forests. The researchers had used the satellite data to study the extent to which forests had absorbed carbon released into Earth’s atmosphere in the form of carbon dioxide from fossil-fuel combustion. Many scientists consider atmospheric accumulation of carbon dioxide to be a primary cause of global climate change, because forests act as “sinks,” absorbing carbon dioxide, thereby reducing its atmospheric accumulation. The researchers had found that forests in Europe, Russia, and the United States annually absorbed almost 700 million tonnes (771 million tons or 1.5 trillion pounds) of carbon from 1981 to 1999. They had also found geographic variations in carbon absorption, with Russian forests accounting for nearly 40 percent of the carbon sink and Canadian forests losing carbon. The findings were significant, because they indicated which forests had lost carbon and which had stored it. The findings also validated relationships between satellite measurements and ground-based measurements of carbon absorption, demonstrating the crucial importance of satellites in monitoring forests. NASA’s Earth Science Enterprise, dedicated to understanding human-induced and natural changes in Earth’s environment, had funded the research. (NASA, “Satellite Data Help Researchers Track Carbon in Northern Hemisphere Forests,” news release 0 1-242, 11 December 2001; Ranga B. Myneni, “A Large Carbon Sink in the Woody Biomass of Northern Forests,” Proceedings of the National Academy of Sciences 98, no. 26 (18 December 2001): 14784–14789.)
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