THE space shuttle Discovery has blasted into orbit from Kennedy Space Centre carrying seven astronauts and the key unit of the Japanese Kibo research module to the International Space Station (ISS).
"Discovery flying true, speeding toward a date with the International Space Station Monday,`` a NASA official announced, describing the launch as "a man-made rising sun on behalf of Japan``.
One Japanese and six American astronauts earlier strapped in tight in the shuttle with perfect weather and no technical troubles to slow the countdown toward a launch to the International Space Station.
Just an hour before the 7am (AEST) blastoff, workers closed the hatch to the space shuttle and moved away from the launchpad.
Scores of Japanese and other dignitaries were at Kennedy Space Centre to witness the shuttle carry up the main segment of the Japan Aerospace Exploration Agency`s (JAXA) Kibo research station to the ISS.
Also aboard were plumbing parts for the ISS toilet, which malfunctioned earlier this week forcing the three ISS astronauts to rig up a still-troublesome bypass for liquid waste.
NASA officials were happy about the trouble-free progress of the launch countdown, especially since nagging problems with ecosensors on the external fuel tank delayed several launches in 2006.
"It`s one of the smoother ones I`ve seen in quite a while,`` said NASA spokesman George Diller.
"There hasn`t been anything`` to mar the preparation, he said.
The seven Discovery crew - six men, one woman - in their bulky orange spacesuits were put into their horizontal seats on the shuttle three hours ahead of the launch, going through checklists to prepare for the flight.
The centrepiece of the 14-day mission is to deliver and install the 11.2 metre, 14.8 tonne pressurised module of Kibo, which means Hope in Japanese.
When in place, it will be the single largest room on the ISS, with space for four scientists to work.
Another key Kibo unit, its 10-metre robotic arm, to be used for manipulating materials and equipment for science experiments, is being sent up on the shuttle.
Installation of the JPM will be overseen by JAXA astronaut Akihiko Hoshide, also flying aboard Discovery.
Discovery is also carrying up a last-minute payload of much-needed parts for the ISS`s Russian toilet, which partially failed this week.
The three astronauts living on the station were forced to use the facilities in the attached Soyuz spacecraft before they could rig up a temporary fix to the toilet, but that fix requires extra manpower and excess water to flush.
The crew will include a replacement astronaut for the ISS, with US robotics specialist Greg Chamitoff stepping in for another American, Garrett Reisman, who will return to Earth after three months at the station.
Three spacewalks are planned for the mission, including one in which an astronaut will attach himself to a massive robotic arm for a soaring, 20-minute ride through space to replace a depleted nitrogen tank, in a giant arc NASA officials described as a "windshield wiper motion.``
"It will be a pretty spectacular ride,`` said spacewalker and mission specialist Ronald Garan, 46.
It is the second of three missions to take up key components of Kibo, which will host experiments in space medicine, biology and biotechnology, material production, and communications.
Kibo`s third main section, a "terrace`` outside the JPM completely exposed to outer space, is to be delivered by a shuttle flight in March 2009.
When fully assembled, Kibo will complete the architecture of the ISS, built together with the United States, Russia and Europe.
