US space shuttle Endeavourblasted off from its seaside launch pad at Cape Canaveral, Florida, yesterday, ending a month of delays to a mission intended to complete construction of Japan's Kibo research laboratory on the International Space Station.
On its sixth launch attempt, Nasa's 127th space shuttle mission began at 6.03pm local time when Endeavour's twin solid-fuel booster rockets ignited, sending the 4.5 million pound (2.04 million-kg) spaceship into the Florida sky.
The shuttle was visible over Ireland last night after take-off, and the craft and International Space Station can be seen over the next few days as they pass over the country.
Astronomy Ireland has a text service (text SPACE to 57003) and phone line (1550 111 442) through which people can get the latest location predictions.
Texts cost €1 per message received, and calls cost 95c per minute, and income from both will help to promote astronomy and science.
"The weather is finally cooperating, so it is now time to fly," launch director Pete Nickolenko radioed to the crew shortly before liftoff. "Persistence pays off. Good luck and godspeed."
Riding atop a pillar of smoke and flame, the shuttle soared over the Atlantic Ocean en route to an orbital rendezvous with the space station tomorrow, 220 miles above Earth.
Two launch attempts last month were scuttled by hydrogen fuel leaks. A third attempt on Saturday ended when Nasa ordered checks of the shuttle's electrical systems following a spate of lightning strikes, and Sunday, and Monday launch attempts were cancelled due to poor weather.
Nasa is trying to complete construction of the $100 billion outpost, a project of 16 nations, by September 30th, 2010, so it can retire the shuttle fleet and speed up development of replacement ships that can journey to the moon and other destinations farther from Earth.
Endeavouris carrying a Japanese-built platform to be mounted on the front of the $2.4 billion Kibo complex to hold science experiments that need to be exposed to the open environment of space.