CAPE CANAVERAL, Fla. - Although shuttle Columbia operated smoothly in orbit, an electrical short and small hydrogen leak experienced during launch are significant problems that need to be understood before the next shuttle mission, a NASA shuttle manager said Wednesday.

"The [circuit] short we saw during ascent, I would consider a significant anomaly that we will have to look at in depth," Bill Gerstenmaier, shuttle integration manager at the Johnson Space Center, said after Columbia's landing Tuesday night.

The short about five seconds after Columbia's liftoff zapped two of the shuttle's main engine controllers, leaving commander Eileen Collins and her crew with no backup. If another short or problem had taken out additional engine computers, the crew likely would have attempted an emergency landing.

"I listened to those abort calls all the way uphill," Collins said at a post-landing briefing on Wednesday.

A second unrelated problem unfurled the moment of liftoff, when the shuttle's engines started burning more oxygen than intended. Photographs taken during launch show a possible leak in one of the engines, which could account for the oxygen shortfall that left the shuttle in a slightly lower orbit than planned. After landing, television cameras showed pictures, confirming damage inside the engine nozzle, which is lined with more than 1,000 cooling tubes, each about three-eights of an inch in diameter. Gerstenmaier said about three to four of the tubes seem to have cracked or split open. The tubes circulate hydrogen to cool the nozzle and condition the propellant for combustion by the shuttle engines.

"It looks like several of the tubes are damaged in the nozzle and it looks like we had a real hydrogen leak there," said Gerstenmaier. "That's also a very significant problem we need to look at and work on."

Still, Gerstenmaier said the real significance of the glitches is that the shuttle's backup systems worked and Collins and her crew were able to safely get to orbit and complete a successful mission.

Added five-time flier Steve Hawley, the shuttle's flight engineer, "We train so you begin to act instinctively and without hesitation. We all felt reasonably comfortable that we were in an environment that we could handle."

Collins, who became the first woman to land the shuttle, said the problems definitely need a close, hard look. "We don't want this to happen on a future mission."

She said she was looking forward to spending time with her three-year-old daughter and her husband. "I'm very happy," said Collins, 42. "I just feel elated this mission went so well and so successfully."