Nasa's Discovery shuttle has blasted off from the Kennedy Space Center in Florida on a 14-day mission to the International Space Station (ISS).
The shuttle and its crew of seven are delivering a giant cylinder for Japan's Kibo science lab but also a new pump to repair the station's toilet.
The toilet in the Zvezda service module failed last week.
Discovery's flight is the third orbiter mission of 2008 and the first to fly the "in-line" external fuel tank.
The new fuel tank has been built from the ground up with the upgrades demanded after the Columbia disaster in 2003.
The improvements are designed to minimise the shedding of insulation foam on launch - the problem that doomed Columbia and her crew.
All missions prior to Discovery's have had the upgrades retrofitted on to tanks that were already constructed.
The shuttle took off into a brilliant blue sky at 1702 local time (2102 GMT) on Saturday. The orbiter is due to dock with the ISS on Monday.
The JPM - seen here in Japan - fills Discovery's entire payload bay
Nearly 400 Japanese journalists, space programme officials and other guests crowded into the launch site, their excitement growing as the hours, then minutes, counted down, the Associated Press reports.
Discovery's primary task is to install the Japanese Pressurised Module (JPM) which is the size of a school bus and will place the Japanese at the forefront of space exploration, the BBC's Andy Gallacher reports from Florida.
The cylinder is the third science laboratory intended for the orbiting platform, after the US Destiny and European Columbus segments.
Once the main Kibo (English: Hope) section is attached to the ISS's Harmony connecting node, the Japanese Logistics Module (JLM) can be moved from its temporary berth and slotted directly on to a larger Japanese unit.
The JLM was sent up on the last shuttle flight and holds all the internal systems and payload racks for the JPM. These will be transferred across to the soon-to-arrive module.
A 10m-long (33ft) robotic arm is also travelling up with the Discovery for use on Kibo.
It will be used to position and retrieve experiments from a platform due to be delivered next year - the final part of the Kibo complex.
Since the urinal side of the toilet failed, the ISS crew have periodically had to flush the unit manually - an operation which takes two people 10 minutes to do.
ISS astronauts will be relieved to get their toilet working properly again
The solid-waste part of the Russian-built toilet is working properly.
A replacement pump was rushed from Russia to be loaded on to Discovery for delivery to the ISS.
Three spacewalks, of some 6.5 hours each, are currently planned for Discovery's mission, mainly for setting up the Kibo equipment.
Astronauts will also deliver a nitrogen gas tank and inspect damage to a key joint that helps the station's power-generating solar arrays to follow the Sun.
Discovery is carrying a special guest on the flight - the space ranger Buzz Lightyear.
The 30cm-tall (12in) action figure, made famous in the Disney/Pixar Toy Story movies, is going into orbit as part of an educational programme.
Nine further shuttle flights are required to complete the ISS before the orbiter fleet is retired in 2010.
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.