Schoolteacher-turned-astronaut Barbara Morgan helped operate a 100-foot robot arm and extension boom in a hunt for damage on her first full day in orbit Thursday, as NASA said foam insulation may have hit the space shuttle at launch.

"Hey, it's great being up here," Morgan said in her first televised update from space. "We've been working really hard, but it's a really good, fun kind of work."

Nine pieces of foam insulation broke off Endeavour's fuel tank during liftoff Wednesday evening, and three pieces appeared to strike the shuttle, said John Shannon, chairman of the mission management team. None is believed to have been big enough to cause critical damage, he said.

The possible strike areas on Endeavour will receive special focus when astronauts aboard the international space station zoom in for pictures of the shuttle before Friday afternoon's linkup.

The first foam fragment came off at 24 seconds after liftoff and appeared to hit the tip of the body flap. The second was 58 seconds after liftoff with a resulting spray or discoloration on the right wing. The third came almost three minutes after liftoff, too late to cause any damage to the wing.

The most worrisome is one that appeared to hit the shuttle's right wing.

"Whether it caused damage or not, we will find out in great detail" during Friday's rendezvous, Shannon said Thursday night. "The report initially was that you got a spray of debris from this area and, of course, that brings up images of Columbia and the spray you saw there, and I would tell you this was not even remotely of the same magnitude."

The foam chunk that pierced the space shuttle Columbia's left wing was 1.67 pounds. The resulting gash led to Columbia's catastrophic re-entry on Feb. 1, 2003.

Shannon said it's impossible to estimate the size of the foam fragments because engineers are unsure where they came from on the external fuel tank.

Pictures of the tank, as it fell away eight minutes into the flight as planned, showed no big gaps in the foam, he said, so NASA is hopeful any damage to Endeavour would be minimal.

Some of the pieces of flyaway foam from Endeavour's fuel tank were so small that flight controllers had trouble seeing them on the video, Shannon said.

Working from the cockpit, Morgan and crewmate Tracy Caldwell slowly swept the laser and camera-tipped boom just above Endeavour's nose cap. Then Morgan was joined by Rick Mastracchio for a similar inspection of Endeavour's left wing.

The right wing — where two pieces of foam are believed to have struck — was checked earlier in the day.

Engineers on the ground scrutinized the images, looking for any cracks or holes. The analysis was expected to last well into the night.

The meticulous survey has been standard procedure ever since the Columbia disaster. The 50-foot boom, attached to the shuttle's 50-foot robot arm, was created expressly for the job.

Endeavour's seven astronauts had their sleep interrupted early Thursday when an alarm went off, alerting them to pressure trouble with the tank.

They later managed to work around the problem by manually turning the tank's heaters on and off to control the pressure and flow of oxygen. Officials described the failed pressure-control sensor as an inconvenience.

NASA hopes to keep Endeavour in orbit for a full two weeks. The shuttle is equipped with a new system for drawing power from the space station. If it works, mission managers plan to extend the flight from 11 days to 14 days.

Morgan, 55, a former elementary schoolteacher from Idaho, was Christa McAuliffe's backup for the inaugural teacher-in-space flight aboard Challenger in 1986. McAuliffe never made it to space; she was killed along with her six crewmates just over a minute after liftoff.

NASA invited Morgan into the astronaut corps in 1998. She was supposed to fly aboard Columbia at the end of 2003, but found herself waiting again after her ship was destroyed and the remaining fleet was grounded.

Now, finally in orbit, Morgan plans to answer questions next week from schoolchildren in at least one state — Idaho — and is flying 10 million basil seeds for eventual distribution to students and teachers.

Morgan offered a sneak preview late Thursday, describing how she felt upside down her entire first day in space, "even though I kept my head upright so it looked like a normal ceiling and a normal floor and normal walls."

The other surprise, she said, was how easy it is to lose things in weightlessness.

"Even if it has Velcro on it, you set it aside and within 30 seconds it's gone and you have no idea where it went to," she said with a smile.