ORLANDO, Fla., July 12 (UPI) -- NASA's Hubble Space Telescope is broken, and the agency is struggling to understand the workhorse observatory's most serious problem in more than a decade.
Hubble stopped working suddenly June 13 while astronomers were using the 31-year-old telescope to examine pulsating stars 200 million miles away.
NASA is trying to understand what went wrong on the orbiting telescope, without which hundreds of astronomy investigations had to be put on hold or canceled. At stake are efforts to understand galaxies, comets, stars, exoplanets and the entire universe.
Engineers have tried to restart the $1.5 billion telescope, which is about 43 feet long -- the length of a typical school bus -- and was named for astronomer Edwin Powell Hubble, who made a number of important discoveries before he died in 1953.
The team is preparing techniques to switch on secondary regulators that control data and power, NASA's astrophysics director Paul Hertz said in an interview. A failed piece of hardware on those regulators is the likely culprit, he said.
"Pretty much everything on Hubble, with some exceptions, is fully redundant, meaning there is a backup if something fails," Hertz said. "We can't say for sure exactly what is wrong, but we think it's a failure on a component that we're trying to isolate."
He said a solution is "likely," but he acknowledged there's a small possibility a fix from Earth isn't possible.
A team of about a dozen people at NASA's Goddard Space Flight Center in Maryland will test procedures to safely turn on backup components, which Hertz said is complicated due to the remote nature of the work and Hubble's suite of delicate high-tech instruments.
NASA does not have a spacecraft designed to service Hubble, which was deployed by space shuttle Discovery in 1990, Hertz said. The telescope orbits the Earth about 340 miles high, or roughly 80 miles higher than the International Space Station.
NASA performed a similar fix to Hubble in 2008 by switching on backup components. Then, in 2009, astronauts installed new backup equipment on a final shuttle trip.
Because the exact nature of the problem isn't known, the agency cannot predict how long a fix will take. While some astronomy can be accomplished by other telescopes, Hubble is unique. It can make clear observations up to 15 billion light-years away, farther than any other orbiting observatory.
NASA has hoped that Hubble would work in tandem with the James Webb Space Telescope, due to be launched from Florida's Kennedy Space Center in November.
The agency describes the new, more powerful telescope as a successor, not a replacement, for Hubble. That's because Hubble sees in optical light, while the James Webb telescope will see the universe in infrared light and be able to look a few hundred million light-years farther than Hubble.
Hubble has enabled ground-breaking astronomy, astrophysicist Adam Reiss said.
"We were in the middle of observations of pulsating stars when it stopped working," Reiss said. He is a professor of space studies at Johns Hopkins University in Baltimore.
"It was obviously concerning, but we are confident NASA will get it working again," he said. "Hubble's kind of a cat with nine lives, so to speak."
Hubble's accomplishments include observations of supernovae that allowed Reiss and Australian physicist Brian P. Schmidt to describe the expansion of the universe, work for which they were awarded a Nobel Prize.
"Hubble was absolutely critical in making some of those measurements," Reiss said. "It is sort of irreplaceable, and we're really hopeful that we'll get it back."
Canceled projects that may be rescheduled include observations of young stars, studies of galaxy centers that were to occur every other day for six months to determine variations in light and observations of the comet 288P to determine if it is a triple comet, NASA spokeswoman Alise Fischer said.