The U.S. space agency NASA is preparing the space shuttle Endeavour for a Monday launch, its final voyage before retiring and the next-to-last launch for the 30-year space shuttle program.
The Endeavour mission was originally supposed to begin in late April, but electrical problems forced repeated delays.
The flight to the International Space Station is commanded by astronaut Mark Kelley, who is the husband of U.S. Congresswoman Gabrielle Giffords, who was critically wounded during a shooting rampage in the state of Arizona in January.
Giffords is expected to attend Monday's launch (0856 EDT, 1256 UTC) at the Kennedy Space Center with an expected 500,000 other spectators. Weather forecasters say there is a 70 percent chance of good weather for the launch.
Kelly and the rest of the five member Endeavour crew will conduct space walks, deliver parts and physics equipment and do some maintenance on the space station during the 16-day flight.
NASA finishes its shuttle program for good with the scheduled launch of Atlantis in July. A third shuttle, the Discovery, returned from its final flight in March.