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After 30 years in orbit, the joint NASA-JAXA Geotail spacecraft’s mission has ended following the failure of the spacecraft’s remaining data recorder. Since its launch on July 24, 1992, Geotail has launched into orbit and collected a vast amount of data on the structure and dynamics of the magnetosphere, Earth’s protective magnetic bubble.
Geotail was originally intended for a four-year period, but the mission was extended several times due to the high quality of the data, which contributed to more than a thousand scientific publications. While one of Geotail’s two data recorders failed in 2012, the second continued to operate until an anomaly occurred on June 28, 2022. After attempts to remotely repair the recorder failed, the mission was terminated on November 28, 2022.
“Geotail has been a very productive satellite, and it was the first joint NASA-JAXA mission,” said Don Fairfield, a space scientist emeritus at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and NASA’s first project scientist for Geotail until his retirement in 2008. “The mission made important contributions to our understanding of how the solar wind interacts with the Earth’s magnetic field to produce magnetic storms and auroras.”
With an elongated orbit, Geotail sailed through the invisible confines of the magnetosphere, collecting data on the physical processes at play there to help understand how energy and particle flow from the sun reaches Earth. Geotail has led to many scientific breakthroughs, including helping to understand how quickly material from the sun enters the magnetosphere, the physical processes at play at the boundary of the magnetosphere, and identifying oxygen, silicon, sodium and aluminum in the lunar atmosphere.
The mission also helped pinpoint the location of a process called magnetic reconnection, which is a major conveyor of material and energy from the sun to the magnetosphere and one of the instigators of the auroras. This discovery paved the way for the Magnetospheric Multiscale mission, or MMS, which launched in 2015.
Over the years, Geotail has collaborated with many other NASA space missions, including MMS, Van Allen probes, Time History of Events and Macroscale Interactions during Substorms mission, Cluster and Wind. With an orbit that sometimes took it as far as 120,000 miles from Earth, Geotail helped provide additional data from distant parts of the magnetosphere to give scientists a complete picture of how events in one area affect other areas. Geotail has also been linked to ground observations to confirm the location and mechanisms of auroras formation.
Although Geotail has finished collecting new data, the scientific discoveries are not over yet. Scientists will continue to study Geotail’s data for years to come.
Bron: NASA
