NASA gave the shuttle Columbia astronauts permission Saturday to proceed with their full mission to renovate the Hubble Space Telescope despite clogged plumbing in their ship.

Optimism had been growing throughout the day, aboard Columbia and inside Mission Control, that the 11-day Hubble servicing mission would remain on track despite a problem with a radiator line used to shed heat from shuttle electronics. The trouble had threatened to cut short the flight.

Debris in the line, possibly leftover from a welding job during Columbia's recent overhaul, resulted in a violation of flight safety rules during Friday's launch.

But mission director Phil Engelauf emphasized that engineers had become more comfortable with the reduced flow of Freon in that loop, and that it would be sufficient for handling the increased heat load from shuttle systems during landing.

The final decision by mission managers came late in the afternoon as the seven astronauts slept. It means the crew can press forward with Sunday morning's rendezvous with Hubble and five days of spacewalks to improve the telescope's electrical and scientific output.

Columbia's commander, Scott Altman, said earlier in the day that he and his crew were "charging ahead full speed with our eyes on the goal," regardless of what the outcome might be.

"To be honest, we've gone on the assumption that we're here to stay, that we're going to do our job, and we've just kind of kept that thought foremost in our minds," he said in an interview with The Associated Press.