(AP) -- NASA is counting down to the final launch of space shuttle Atlantis.
Atlantis is set to blast off Friday afternoon on its last trip to the International Space Station. The countdown clocks began ticking Tuesday.
Forecasters put the odds of good launch weather at 70 percent.
The six astronauts assigned to the mission arrived at Kennedy Space Center on Monday evening. Atlantis will deliver spare parts and supplies to the International Space Station.
NASA will wrap up the shuttle program this fall. Two more missions are planned, by Discovery and Endeavour. NASA test director Steve Payne says the launch team is savoring the moments while it can.
Atlantis' launch on Friday is 2:20 p.m.
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