The space shuttle Discovery is heading for its rendezvous with the International Space Station.
Officials at the US space agency, NASA, say material fell off the fuel tank of the shuttle, after its launch from Cape Canaveral in Florida last night.
An official said several small pieces of debris were seen dropping off but it was unclear whether they were pieces of insulating foam or other material.
However, NASA said there was no reason to have any concern for the safety of the crew.
The spacecraft is taking seven astronauts on a 12-day mission to the ISS to test new safety procedures and to deliver supplies.
The launch of Discovery was postponed twice over the weekend due to bad weather.
