Artist's impression of the GALEX spacecraft, an orbiting telescope studying the universe at ultraviolet wavelengths.
Orbiting observatory recovers from computer glitch
3 July 2008
NASA's Galaxy Evolution Explorer (GALEX) resumed nominal operations on July 1, completing recovery from its June 13 shutdown, caused by an anomaly with the satellite's instrument processor. Over the last week, the team of engineers and scientists had been bringing the instrument slowly on-line in order to test various operational modes.
On June 13, the processor caused the science instrument to shut down. The GALEX team now believes that the processor might have attempted to respond to erroneous signals, triggering it to halt. During its orbit around Earth, GALEX is continuously subjected to elevated levels of radiation, which might have corrupted a portion of the contents of the computer memory.
Changes have been made to the instrument software to reduce the likelihood of a recurrence. Additional changes were also included to assist in identifying the specific area causing the processor to halt, should it happen again. The instrument is currently on and the temperature of the telescope is being adjusted.
GALEX is an orbiting space telescope observing galaxies in ultraviolet light across 10 billion years of cosmic history. A Pegasus rocket launched GALEX into orbit on April 28, 2003. Although originally planned as a 29-month mission, a NASA Senior Review Panel in 2006 recommended that the mission lifetime be extended.
GALEX’s observations are telling scientists how galaxies, the basic structures of our Universe, evolve and change. Additionally, GALEX observations are investigating the causes of star formation during a period when most of the stars and elements we see today had their origins.
Led by the California Institute of Technology, GALEX is conducting several first-of-a-kind sky surveys, including an extra-galactic (beyond our galaxy) ultraviolet all-sky survey. GALEX is also producing the first comprehensive map of a Universe of galaxies under construction, bringing us closer to understanding how galaxies like our own Milky Way were formed.
Scientists would like to understand when the stars that we see today and the chemical elements that make up our Milky Way galaxy were formed. With its ultraviolet observations, GALEX is filling in one of the key pieces of this puzzle.
Adapted from information issued by NASA.
