Bill Jeffs said the final switch-on of the Endeavour shuttle's engines has been postponed due to space debris from a Russian satellite being in the shuttle's path.
NASA's STS-126 mission, dubbed "extreme home improvements," started on November 14 when Endeavour took off from Cape Canaveral in Florida with a crew of seven and 14,000 kg of supplies.
"STS-126 arrived at the station Nov. 16, delivering equipment that will help allow the station to double its crew size to six. The gear included two sleep stations, a new galley, a water recovery system and an advanced resistive exercise device," NASA said on its website.
"Astronauts also performed four spacewalks. Among their accomplishments were cleaning, lubricating and installing new bearing assemblies on the starboard Solar Alpha Rotary Joint," NASA said.
Endeavour's landing is scheduled for Sunday at 18:19 GMT. Seven astronauts on the Endeavour mission will return to Earth, along with current ISS astronaut Greg Chamitoff, replaced by Sandra Magnus, who is due to remain on the space station until February next year.
