CAPE CANAVERAL, Florida (AFP) – NASA said Thursday that debris that peeled off from the space shuttle Endeavour's external fuel tank as it blasted off one day earlier was no cause for concern.

The debris was spotted after the shuttle took off Wednesday from the Kennedy Space Center, its sixth bid in recent weeks to reach the International Space Station (ISS) after delays caused by weather woes and technical glitches.

"There is nothing that we have seen on the orbiter that causes any concern," space shuttle manager John Shannon said at a press conference.

The debris could be seen hitting the shuttle about two minutes into the flight in images broadcast on NASA TV.

"It didn't hurt us apparently on this flight because it came off so late" in the ascent, Shannon said, adding that NASA specialists would look at the issue more closely.

"We need to understand, since this looks like a new mechanism of shedding foam off the intertank... we need to understand that for the next flight," he said.

Earlier Thursday, NASA's associate administrator for space operations, Bill Gerstenmaier, said the debris could be ice or foam that broke off from the external fuel tank.

"We had some foam loss events," Gerstenmaier told reporters. "You can clearly see, on the front part of the orbiter, some white indications where the tiles were dinged.

"We don't consider those an issue for us, those are probably coating losses," he said.

Endeavour astronauts used the shuttle's robotic arm for what the space agency called "the standard flight day two inspection" of the reinforced carbon wing leading edge and nose cap.

The astronauts were to transmit the images to experts on the ground that will scour them for any anomalies, according to information on the National Aeronautics and Space Administration website.

NASA has been cautious about conditions for the space shuttle's exit and return since the shuttle Columbia blew apart some 20,000 meters (65,500 feet) above the Earth in 2003 as it was returning from a 16-day space mission to land in Florida.

A chunk of insulation that broke off from the shuttle's external fuel tank during takeoff had gouged Columbia's left wing heat shield, allowing superheated gases to melt the shuttle's internal structure before it exploded, killing all seven astronauts onboard.

The six Americans and one Canadian aboard Endeavour are scheduled to reach the ISS on Friday, where they will complete the Japanese Kibo laboratory, a platform for astronauts to conduct experiments 350 kilometers (220 miles) above Earth's surface.

NASA on Thursday piped in the song "These Are Days" by the band 10,000 Maniacs for the Endeavour's crew wake-up, "targeted especially for Mission Specialist Tim Kopra," the space agency said.

The Endeavour mission aims to help fulfill "Japan's hope for an out-of-this-world space laboratory," as the shuttle delivers state-of-the-art equipment to conduct experiments in the vacuum of space, NASA has said.

The ISS should be completed in 2010, also the target date for the retirement of the US fleet of three space shuttles.