The very last space shuttle flight before NASA retires the 30-year program is targeted to launch on July 8, space agency officials announced Friday. The shuttle Atlantis is slated to carry four veteran astronauts to the International Space Station to deliver supplies and spare parts for the orbiting outpost. NASA is targeting to launch Atlantis from the Kennedy Space Center in Florida on July 8 at around 11:40 a.m. EDT. The target launch date for Atlantis' 12-day mission is based on NASA's current planning. An official launch date will be announced following the mission's Flight Readiness Review on June 28. During the final shuttle flight, Atlantis also will deliver an experiment "to demonstrate and test the tools, technologies and techniques needed to robotically refuel satellites in space – even satellites not designed to be serviced," NASA officials said in an announcement. The four-astronaut crew will return an ammonia pump that failed on the space station in July 2010. Engineers want to understand why the pump failed and hope to use the knowledge to improve designs for future spacecraft. STS-135 will be Atlantis' 33rd and final mission before it is retired, along with the rest of the agency's orbiter fleet. The historic flight will be the 135th and final mission of NASA's space shuttle program. The space shuttles are retiring in order to make way for a new space exploration program aimed at sending astronauts on deep space missions to visit an asteroid by 2025, and then aim for Mars.