After a careful consideration of the available options, NASA’s scientists decided on switching over to a backup computer, which might get the Hubble Space Telescope ready for work by the end of the week.

The problems began about two weeks ago when the telescope encountered issues with some of its circuits. One of the data formatters failed to complete its tasks of capturing and beaming down photos. This error led to a significant delay in the agency’s shuttle Atlantis mission plans. The flight was supposed to complete the last on-orbit maintenance of the telescope and has been rescheduled for mid-February, in order to complete a full verification and make sure that no other surprises will occur. The agency’s officials explained that each month of delay costs NASA more than $10 million.

The Atlantis mission is scheduled to complete five space walks needed to add new cameras and docking equipment, replace several old batteries and gyroscopes, and also upgrade the telescope’s guidance system. In addition to these tasks, the astronauts will also attempt to fix a spectrometer and the telescope’s main survey camera – both designed to be repaired on Earth.

Over the past two weeks there have been many tests made, as there are several concerns about these electronic components that should be used and whether they will be able to support the tasks. The reason why this uncertainty is present is because the backup components haven’t been used before in the telescope’s 18-year-long history. This week, the backup data formatter and the spare data handling unit will be used for the very first time, and considering that 18 years is indeed a very long time, there have been many scenarios considered by the scientists.

Still, the general belief is that everything will turn out fine. "We have very good confidence this will work," said Art Whipple, the Hubble systems manager at NASA's Goddard Space Flight Center in Greenbelt, Md., even though he admitted that it is truly a complicated procedure that has never been done end to end before. He also added that there have been many inactive 15-year-old components on other satellites that worked just fine once they were powered.

Jon Morse, director of astrophysics at NASA headquarters, is also very optimistic about the chances of success, saying that “It’s everyone’s goal to see wonderful science coming back from the telescope again.”

In order to complete the switchover, NASA will have to complete a safe mode reboot session in order to safely reroute the circuitry. If everything goes according to plan, the first signals should be received from one of the science instruments late Thursday and the full restoration should be completed on Friday.

"The most critical part of the commanding will happen between 8:30 a.m. and 11:00 a.m. Eastern time," Whipple said about today’s activity. "We expect the full flow of science to resume Friday morning."

The reboot mission will be conducted from NASA’s Goddard Space Flight Center in Maryland by a team of over 40 engineers and scientists.