By Irene Klotz
NASA delayed the landing of the space shuttle Discovery because of stormy weather at its Florida landing site, but planned to try again later on Thursday to bring the spacecraft home,
Discovery and its seven astronauts are returning from a 13-day supply mission to the International Space Station.
NASA skipped the shuttle's first landing opportunity at 7:04 p.m. EDT (2304 GMT) and said it was hoping for a break in the clouds and crosswinds before the second landing opportunity at 8:40 p.m. EDT on Thursday (0040 GMT on Friday).
"The weather is very unstable down at KSC," NASA commentator Rob Navias said, referring to the Kennedy Space Center in Florida.
The landing time already had been tweaked because the Discovery crew had to alter its path slightly to steer clear of a piece of space debris.
NASA did not know what the space junk was, except that it likely came from the shuttle or the space station on Saturday during the last of the Discovery crew's three spacewalks.
"Exactly what (the debris) is not known, but it's been moving toward the orbiter, so it is a concern," said mission commentator Pat Ryan.
During Discovery's nine-day stay at the station, two other pieces of orbital debris sent engineers scrambling to prepare avoidance maneuvers, which were later determined to be unnecessary. Those pieces of space junk were identified as part of a spent upper-stage European rocket motor and a fragment from an obsolete weather satellite that China destroyed in January 2007 during a widely condemned weapons test.
Discovery blasted off a minute before midnight on August 28 with more than 7.5 tons of food, laboratory equipment, science experiments, spare parts and a new treadmill and crew quarters for the space station.
The space station is a $100 billion project of 16 nations and is nearing completion after more than a decade of construction.
JAPANESE CRAFT LIFTS OFF
As Discovery prepared to return to Earth, a Japanese cargo ship lifted off on a debut flight to the International Space Station.
The H-2 Transfer Vehicle, known as HTV, blasted off from the Tanegashima Space Center in southern Japan at 1:01 p.m. EDT (1703 GMT) aboard an H-2B rocket, also making its maiden flight.
The launch, which was televised by NASA, marked a major milestone for Japan's aerospace industry and a key resource for the space station program, which will soon lose the enormous cargo capacity of the U.S. space shuttles.
The shuttle fleet is being retired due to safety concerns and high operating expenses after six more missions to the space station.
"We are so proud of taking this new responsibility to provide cargo transportation capability to ISS program," said Masazumi Miyake, a project manager with the Japan Aerospace Exploration Agency. "JAXA is now entering a new era."
The HTV, which is expected to reach the station on September 17, is loaded with more than 3 tons of food, equipment, supplies and experiments, including two Earth-monitoring devices that will help track climate change.