London, September 30 : A critical failure on the Hubble Space Telescope has forced NASA to delay its mission to upgrade the observatory until at least February 2009, which will allow the agency to test and prepare a replacement part for launch.
According to a report in New Scientist, the agency had planned to send the space shuttle Atlantis on a mission to repair and upgrade the telescope in just two weeks' time.
But on Saturday, operators discovered problems with a device that stores and transmits most of the probe's science data.
There are actually two identical versions of the device, called the Control Unit/Science Data Formatter, on the telescope.
Side A failed, but engineers hope to bring the identical Side B online in the next few weeks to continue the telescope's science activities.
Still, that will leave Hubble with no backup for the crucial system. So, the agency plans to send up a full replacement, which is currently in storage at the NASA Goddard Space Flight Center in Greenbelt, Maryland.
"We want to make sure we leave Hubble as healthy as we possibly can," said Ed Weiler, NASA's associate administrator for science.
The spare, which was last used in 2001 to test another instrument, will require a battery of tests to determine if it is ready for launch.
If all goes well, the instrument could ship to Florida's Kennedy Space Center by early January, according to Hubble manager Preston Burch of Goddard.
But fitting its installation into the servicing mission may be tricky.
Atlantis's five scheduled spacewalks are already jam-packed with plans to replace two instruments, repair two others, and install all-new gyros, batteries and insulation.
The revamp could give Hubble its best vision yet and extend the telescope's life to at least 2013.
The 60-kilogram (135-pound) control unit is designed to be manipulated by astronauts and could potentially be installed in less than two hours.
The installation could be accomplished on the fifth spacewalk day, part of which has been set aside just in case astronauts need time to wrap up repairs to the telescope's Advanced Camera for Surveys, according to Burch.
Engineers are still investigating what caused the glitch.
"There was no indication of an impending failure," Burch said. "The unit runs at a higher temperature than other components, which might have created some problems," he added.
The launch delay could cost NASA more than 10 million dollars a month and could be a challenge to NASA's already tight launch schedule, since the space shuttles are set to be retired in 2010.