By Paul Rincon

BBC News science reporter, at the Kennedy Space Center



The events were captured in onboard video and the agency says it now needs to consider their significance.

In one case, a heatshield tile seems to have been affected on the underside of the shuttle.

Discovery's astronauts are to use a 15m-long robotic arm to inspect the orbiter's exterior.

The arm is equipped with sensor and camera attachments. A full sweep of the shuttle's key surfaces will take several hours.

It appears the tip of the shuttle's external fuel tank also hit a bird as it launched from Kennedy Space Center on Tuesday.

Spot investigation

John Shannon, STS-114 mission operations representative, pointed out video frames apparently showing a piece of heatshield tile breaking off from the underside of the shuttle.

SHUTTLE RETURN TO FLIGHT Mission known as STS-114 Discovery's 31st flight 17th orbiter flight to ISS Payload: Raffaello Multi-Purpose Logistics Module Lift-off: 1039 EDT, 26 July Location: Kennedy Space Center, Launch Pad 39B Discovery crew: Collins, Kelly, Noguchi, Robinson, Thomas, Lawrence and Camarda

Guide to key shuttle changes

"We're very interested in that," he told reporters. "That's something we're going to get better pictures of on flight-day three."

Mr Shannon said it could simply be that part of the black covering on the orbiter's underside was damaged exposing the heatshield tile.

But he added that it was equally possible the tile itself had been dented or sheared.

The missions operations representative also showed journalists video footage of a dark object falling from the external tank.

Experts cannot yet determine its size, but it did not appear to hit the shuttle, they said.

News outlets had reported details of this piece of debris falling off the tank earlier in the day.

Parts and supplies

Tuesday's successful launch was Nasa's second go at a lift-off in the current launch window.

PERFECT FLORIDA DAY Everything seemed to go right for Nasa and the cheering spectators

In pictures



Nasa says it has learnt the safety lessons of the Columbia disaster, which cost the lives of seven astronauts, and has made this the most scrutinised shuttle flight ever.

Columbia broke up as it attempted to re-enter Earth's atmosphere.

Nasa has been considering the issue of bird-strike on launch

Nasa had positioned more than 100 cameras, both on the ground and in the air, to capture as much detail as possible on Discovery's ascent into orbit.

Discovery will take parts and supplies to the ISS and test new safety features such as a repair-kit for heatshield tiles and a 15m-long robotic arm that will inspect the shuttle for damage in orbit.

Discovery is due to touch down at Kennedy Space Center on 7 August at 0546 EDT (0946 GMT; 1046 BST).