A Japanese H-2A rocket successfully lifted off from its launch pad Saturday carrying a 4.6-ton weather and navigation satellite, officials said.
The launch of the Japanese-developed rocket from the remote southern island of Tanegashima was the ninth of an H-2A, a two-stage launch vehicle.
The liftoff was successful and no problems were immediately reported, said Toshihisa Horiguchi, a spokesman for Japan's space agency, JAXA.
Within half an hour, the satellite was separated from the rocket and was sent toward a designated orbit as planned, JAXA spokeswoman Nobuko Sato said.
"The rocket launch went successfully, but it will take several days before we can find out whether the satellite performs its initial steps and enters the orbit successfully," Sato said.
The satellite would be placed in a geostationary orbit about 22,300 miles above the equator.
Prime Minister Junichiro Koizumi praised the launch.
"I'm delighted by the outcome, which ensured the credibility of the H2-A rocket and demonstrated a steady progress of our nation's space development," he was quoted as saying by the Kyodo News agency. "I hope we can continue to build on this achievement."
The satellite, MTSAT-2, is designed to be a backup for the earlier satellite, put into orbit a year ago and later named Himawari, or Sun Flower, whose mission will end in 2010.
The newer satellite also will be used as an air traffic control satellite to cope with crowded civil flights in the Asia-Pacific region.
In January, JAXA successfully launched an observation satellite on an H-2A rocket.
Japan plans to launch spy satellites by March 2007 and is considering establishing a manned base on the moon by 2025.