The US space shuttle Endeavour on Monday soared into orbit carrying an observation deck for the International Space Station, a seven-windowed dome offering breathtaking views.

The picture-perfect launch lit up the night sky at 4.14am (9.14am GMT), after a first attempt was scrubbed on Sunday due to heavy clouds over the launch pad in Cape Canaveral, Florida.

The spacecraft and its crew of six astronauts reached orbit about eight and a half minutes later.

It was likely the last night-time launch as the shuttle programme nears retirement, with just four scheduled flights left.

"We wish you good luck and Godspeed, and see you in about two weeks," launch director Mike Leinbach told the crew shortly before lift-off.

The Endeavour mission's main goal is to deliver the massive Tranquility module, also known as Node 3, which comes with a multi-window cupola attached. Built for NASA by the European group Thales Alenia Space in their Turin factory, the cupola will provide unparalleled panoramic views of Earth and space.

An important piece of hardware

Six windows arrayed along its sides and another on top ? all protected against the impact of tiny meteorites ? will provide an unprecedented, wide-ranging view for those onboard and help crew members monitor spacewalks and docking operations.

The cupola can accommodate two crew members at a time, and is equipped with portable workstations that can control station and robotic activities.

Installing the Tranquility module amounts to a major construction job, requiring a team of two astronauts to undertake three spacewalks lasting 6.5 hours each, NASA said.

Once the room is in place, the space station will be 90 percent complete.

The module, named after the lunar sea where Apollo 11 landed, has the most sophisticated life support system ever flown into space ? air revitalisation, oxygen generation and water recycling systems, as well as a waste and hygiene compartment for the crew.

The blast-off was "an important event," said Jean-Jacques Dordain, European Space Agency director general.

"Even more important for us because the shuttle was full of European hardware," he said.

NASA's new focus

The mission, one of five scheduled for NASA's three shuttles before the programme ends later this year after a 29-year run, comes as the US space agency re-evaluates its future after President Barack Obama effectively abandoned its plan to send astronauts back to the moon by 2020.

The Constellation programme was intended to develop a successor spacecraft to the shuttle, which could carry astronauts to the moon. They could then use a lunar base to launch manned missions to Mars.

Constrained by soaring deficits, Obama submitted a budget to Congress that encourages NASA to focus instead on developing commercial transport alternatives to ferry astronauts to the ISS after the shuttle programme ends.

Tranquility is seven metres (23.6 feet) long and has a pressurised cylindrical hull 4.5 metres (14.5 feet) in diameter, with a shallow conical section enclosing each end. Together with the cupola, it weighed more than 16.5 tons at launch.

The ISS, a joint project involving 16 countries, has cost around $100-billion, mostly funded by the United States.

Under Obama's new budget, the floating research station could see its life extended by five years until 2020.