Weird objects in shuttle video

I'm watching a live video feed on NASA TV now, which is broadcasting the footage recorded by Soichi Noguchi (by handheld camera) seconds after the external fuel tank separation took place (not the stationery one shown on tv so far). It shows the tank slowly drifting away from the shuttle to finally end up burned in the upper atmosphere but it also shows some white chunks of some kind of wierd 'debris' floating between the space shuttle and the tank. First two are seen just a minute into the video and the other one about 6-8 min. The third one is huge and has a oval shape, kinda like a half of a barrel.

I wonder what it is and what part of the orbiter/tank is came from?
Sounds like more problems maybe be unfolding now.

(and no it's not a UFO or any kind of alien stuff).

STS-114 Space Shuttle Mission Launched Successfully

Congratulations to the whole NASA team who worked hard to continue the space exploration program, which will benefit future generations.

I've heard opinions that if this mission failed the whole shuttle program would have been cancelled. That would only set the space program back to pre-moon era.

Great live NASA TV stream currently covering the whole mission: http://www.nasa.gov/multimedia/nasatv/index.html