Hubble up and running
Scientists virtually solve a sticky engineering problem
After a close call with a computer malfunction, NASA’s Hubble Space Telescope is again taking pictures of the heavens. The agency said the telescope malfunctioned on June 13 when one of the many computer systems aboard the orbiting telescope appeared to fail.
Initially, NASA engineers suspected a part of the satellite’s system that still operates on 1980s-era technology. During a spacewalk in 2009, astronauts from the Space Shuttle Atlantis had replaced some of the decades-old computing. But astronauts left in place the telescope’s payload computer, built in the 1980s but first designed in the 1970s.
The Space Shuttle Discovery hauled Hubble into Earth’s orbit in 1990. In the 31 years since, Hubble has made over 1.5 million astronomical observations leading to more than 18,000 scientific papers, according to NASA.
In 1993, astronauts fixed the telescope’s reflective mirror. After a service mission in 1999 by Discovery and again in 2002 by the Space Shuttle Columbia, the telescope’s final service came in 2009. Without a shuttle fleet to go personally inspect the system, NASA engineers needed to solve the latest problem electronically from Maryland’s Goddard Space Flight Center.
To troubleshoot, NASA engineers switched the payload computer, which coordinates Hubble’s various instruments, to a different memory bank to see if that solved the problem. When that failed, engineers instructed Hubble to switch over to one of the payload computer’s backup systems. But that failed too.
By June 22, NASA engineers at Maryland’s Goddard Space Flight Center suggested the ancient payload computer may not be the source of the problem after all. They began investigating hardware replaced during the 2009 refit. After weeks of switching systems on and off and trying out backup systems in various combinations, engineers finally found a permutation that worked. Using a backup power control unit along with a backup command unit, engineers coaxed the backup payload computer back online on July 16.
Two days later, Hubble was back to snapping pictures of the universe—this time observing a spiral galaxy with three arms. “I’m thrilled to see that Hubble has its eye back on the universe, once again capturing the kind of images that have intrigued and inspired us for decades,” NASA Administrator Bill Nelson said.
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