The NASA-JAXA (Japanese Aerospace Exploration Agency) Geotail spacecraft, which studied Earth's magnetosphere, the protective magnetic bubble of the planet, has retired after 30 years in orbit. The mission operations for Geotail ended after the failure of the spacecraft's remaining data recorder, NASA announced on January 18, 2023.
Geotail was launched on July 24, 1992. Since then, the spacecraft has gathered immense information on the structure and dynamics of Earth's protective magnetic bubble. Originally slated for a four-year run, the Geotail mission was extended several times due to its high-quality data return. Thousands of studies describing the findings of Geotail have been published over the years.
One of Geotail's two recorders failed in 2012. However, the second recorder continued to work until experiencing an anomaly on June 28, 2022. Attempts were made to remotely repair the recorder, but in vain. On November 28, 2022, the mission operations for Geotail were ended.
Scientific breakthroughs achieved by Geotail
In a NASA statement, Don Fairfield, the space agency's first project scientist for Geotail until his retirement in 2008, said Geotail has been a very productive satellite, and it was the first joint NASA-JAXA mission. He added that the mission made important contributions to scientists' understanding of how the solar wind interacts with Earth's magnetic field to produce storms and auroras.
Geotail revolved around Earth in an elongated orbit, and sailed through the invisible boundaries of the magnetosphere. The satellite gathered data on the physical processes at play in the magnetosphere to help understand how the flow of energy and particles from the Sun reach Earth.
Some of the scientific breakthroughs achieved by Geotail include helping scientists understand how quickly material from the Sun passes into the magnetosphere, identifying oxygen, aluminium, sodium, and silicon in the lunar atmosphere, and finding clues about the physical processes at play at the magnetosphere's boundary, the NASA statement said.
With the help of the Geotail mission, scientists identified the location of a process called magnetic reconnection, which is a major conveyor of material and energy from the Sun into the magnetosphere. Magnetic reconnection is one of the factors responsible for instigating auroras.
The orbit of Geotail took the spacecraft over 1,93,121 kilometres away from Earth. The spacecraft also provided scientists with complimentary data from remote parts of the magnetosphere. This helped scientists obtain a glimpse of how events seen in one area affect other regions. Geotail's findings, combined with observations on the ground, helped scientists confirm the location and mechanisms of how auroras form.
Although Geotail has retired, several scientific discoveries using its data are yet to be made.