Is this the last Shuttle mission?

Despite the apparently successful launch of the Space Shuttle Discovery, it has now emerged that a suitcase-sized piece of foam insulation was stripped from the main fuel tank during the ascent to orbit. In response Nasa has grounded the remaining Shuttle fleet and continues to inspect Discovery for damage.. the seven astronauts are about to dock with the International Space Station, but there is a possibility that this could be the final Shuttle mission.