After 17 years of studying the sun and the solar system, the Ulysses solar probe is about to freeze to death, NASA and the European Space Agency have said.
The satellite had long outlasted the five-year mission it began in 1990, but continued to transmit useful data on solar winds. More recently, its plutonium power source had weakened and its fuel was freezing as the probe made a wide circle of the sun, traveling as far as Jupiter.
In January, engineers tried a long-shot manoeuvre to heat up the fuel. But their effort backfired and hastened Ulysses’ death by months.
The $ 250 million probe was a joint ESA-NASA project. After being released from orbit by astronauts on the space shuttle Discovery in October 1990, Ulysses made nearly three full wide circles of the sun from above and below its poles, logging nearly 10 billion km overall.
When the satellite recently started to fail, it had just finished examining the sun’s North Pole for a third time.
“This mission has rewritten textbooks,” said Arik Posner, NASA’s Ulysses program scientist. What made Ulysses unique and crucial to scientists was its orbit and perspective. It provided astronomers with a three-dimensional look at the sun and the rest of the solar system. Most of the planets line up along the same geometric plane generally around the middle of the sun and that is where most of the space probes orbit, too. But Ulysses made long wide circles of the sun’s poles, essentially gazing down at the sun and solar system from above and below instead of around the middle.
That three-dimensional data from Ulysses was important for scientists trying to figure out the solar wind. These winds blast away from the sun at 1.6 million km an hour in all directions, said David McComas, a scientist with the Ulysses project.
The wind is crucial because it protects the earth from cosmic radiation, causes geomagnetic storms on the earth, and causes Aurora borealis. “We understand it now, we did not understand it before,” Mr.McComas said.
Courtesy: AP and The Hindu, February 24, 2008
The satellite had long outlasted the five-year mission it began in 1990, but continued to transmit useful data on solar winds. More recently, its plutonium power source had weakened and its fuel was freezing as the probe made a wide circle of the sun, traveling as far as Jupiter.
In January, engineers tried a long-shot manoeuvre to heat up the fuel. But their effort backfired and hastened Ulysses’ death by months.
The $ 250 million probe was a joint ESA-NASA project. After being released from orbit by astronauts on the space shuttle Discovery in October 1990, Ulysses made nearly three full wide circles of the sun from above and below its poles, logging nearly 10 billion km overall.
When the satellite recently started to fail, it had just finished examining the sun’s North Pole for a third time.
“This mission has rewritten textbooks,” said Arik Posner, NASA’s Ulysses program scientist. What made Ulysses unique and crucial to scientists was its orbit and perspective. It provided astronomers with a three-dimensional look at the sun and the rest of the solar system. Most of the planets line up along the same geometric plane generally around the middle of the sun and that is where most of the space probes orbit, too. But Ulysses made long wide circles of the sun’s poles, essentially gazing down at the sun and solar system from above and below instead of around the middle.
That three-dimensional data from Ulysses was important for scientists trying to figure out the solar wind. These winds blast away from the sun at 1.6 million km an hour in all directions, said David McComas, a scientist with the Ulysses project.
The wind is crucial because it protects the earth from cosmic radiation, causes geomagnetic storms on the earth, and causes Aurora borealis. “We understand it now, we did not understand it before,” Mr.McComas said.
Courtesy: AP and The Hindu, February 24, 2008
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