The Tianzhou-2 cargo spacecraft was to have been launched early Thursday morning. China Manned Space announced the delay on its website but didn't say when the rescheduled launch would occur.

It would be the first mission to the main Tianhe space station module that was launched on April 29. A total of 11 launches are planned by the end of next year to deliver the station's other two modules, various components and supplies and a three-person crew.

The launch of Tianhe, or Heavenly Harmony, was considered a success although China was criticized for allowing the uncontrolled reentry to Earth of part of the rocket that carried it into space. Usually, discarded rocket stages reenter the atmosphere soon after liftoff, normally over water, and don't go into orbit.

NASA Administrator Sen. Bill Nelson said at the time that China had failed to meet responsible standards regarding space debris.

China's space program has suffered relatively few setbacks since it first put an astronaut into orbit in 2003, although the space station launch was delayed by the failure of an earlier version of the massive Long March 5B rocket.