US space shuttle Atlantis, pictured on May 18, as it is prepared for its final flight. NASA said it is aiming for a July 8 lift-off.

NASA said Friday it is aiming to launch the space shuttle Atlantis on July 8 for the last-ever flight of the 30-year-old American shuttle program.

The 12-day mission to the International Space Station (ISS) will be staffed by a smaller than usual crew of four American astronauts, the US space agency said.

"NASA's final space shuttle flight is targeted to launch July 8 at about 11:40 am (1540 GMT) from the agency's Kennedy Space Center in Florida," a statement said.

"Four veteran astronauts will fly aboard shuttle Atlantis to deliver supplies and spare parts to the International Space Station."

An official decision on the launch date and time will be announced following a flight readiness review meeting on June 28, NASA said.

Atlantis was initially set to launch in late June but was postponed after technical woes delayed the Endeavour mission. The shuttle Endeavour launched Monday and is currently docked at the ISS.

The three-decade US shuttle program will end after Atlantis's mission, leaving Russia's space capsules as the sole taxi to the ISS until private companies can come up with a new spacecraft, possibly by 2015.

NASA said some extra tests would be done to ensure that Atlantis is ready to fly, including a special examination of the support beams, known as stringers, for the external fuel tank.

US space shuttle Atlantis on May 18, is lifted in the Vehicle Assembly Building at Kennedy Space Center, Florida. NASA said Friday it is aiming to launch the space shuttle Atlantis on July 8 for the last-ever flight of the 30-year-old American shuttle program.

Cracks in the stringers delayed the Discovery mission in November 2010, though it eventually was cleared for launch in February and became the first shuttle of the space flying fleet to officially enter retirement.

"There are several non-standard activities, including a tanking test followed by an X-ray inspection of a section of the external fuel tank, which may affect Atlantis' processing," NASA said.

A key objective of the Atlantis mission to the orbiting lab is to "deliver an experiment designed to demonstrate and test the tools, technologies and techniques needed to robotically refuel satellites in space," NASA said.

The shuttle will be commanded by NASA astronaut Chris Ferguson, who has flown on two previous shuttle missions. Other crew members will be pilot Doug Hurley and mission specialists Sandy Magnus and Rex Walheim.

The Atlantis mission, STS-135, will be the 33rd space flight for that particular shuttle and the 135th and final mission for NASA's space shuttle program.

After the final shuttle missions, the three spacecraft in the flying fleet and the prototype Enterprise will be sent to different museums across the country.

Discovery, the oldest in the group, was the first shuttle to retire after its final journey to the ISS ended in March. Endeavour, the youngest, and flew its first space mission in 1991 and is currently on its final mission to the ISS.

The other original members of the fleet include Enterprise, which never flew in space; Challenger, which exploded shortly after liftoff in 1986; and Columbia, which disintegrated on its return to Earth in 2003.

A total of 14 astronauts were killed in the Columbia and Challenger disasters.

With the US shuttle program closing, the world's astronauts will rely on Russia's space capsules for transit to the ISS at a cost of more than $50 million per seat.