CAPE CANAVERAL, Fla. — The Hubble Space Telescope should be back in action soon, following a tricky, remote repair job by NASA. 

The orbiting observatory went dark in mid-June, with all astronomical viewing halted. 

NASA initially suspected a 1980s-era computer as the source of the problem. But after the backup payload computer also failed, flight controllers at Maryland's Goddard Space Flight Center focused on the science instruments' bigger and more encompassing command and data unit, installed by spacewalking astronauts in 2009. 

Engineers successfully switched to the backup equipment Thursday, and the crucial payload computer kicked in. NASA said Friday that science observations should resume quickly, if everything goes well. 

A similar switch took place in 2008 after part of the older system failed.

"Congrats to the team!" NASA's science mission chief Thomas Zurbuchen tweeted.

Launched in 1990, Hubble has made more than 1.5 million observations of the universe. NASA launched five repair missions to the telescope during the space shuttle program. The final tuneup was in 2009.

NASA plans to launch Hubble's successor, the James Webb Space Telescope, by year's end.