NASA's Space Shuttle Atlantis landed at Kennedy Space Center's (KSC) 15,000ft (4,500m) long runway at 06:21h local time (10:21 GMT) today after its successful extended 12-day International Space Station (ISS) mission STS-115 to attach the 17,500kg (38,500lb) port three and port four (P3/P4) truss to the orbital outpost.


 Above: Atlantis, OV-104, lands at KSC's runway after its 12-day flight

Atlantis landed a day late because an unidentified object was spotted near to the Orbiter before it began its planned descent on the morning of 20 September. The object turned out to be a bag and NASA's mission management's fears of a possible collision between bag and Orbiter were appeased after an inspection of the spacecraft's thermal protection system found no problems, allowing today's landing.

During the mission, that began with the 9 September launch, the 13.7m (45ft)-long P3/P4 truss was attached to the ISS on flight day four. At about 08:00 GMT on 12 September Canadian Space Agency astronaut Steve MacLean and ISS expedition 13 flight engineer Jeffery Williams used the ISS remote manipulator system to move the P3/P4 truss to its new position at the end of the station's existing port one truss segment.

On the mission's first day of extra-vehicular activity (EVA), NASA astronauts Joe Tanner and Heide Stefanyshyn-Piper connected power cables and removed launch restraints from the array's blanket box and its Beta Gimbal Assembly. The unfolding of the Lockheed Martin-built solar panels was to take place on 13 September but a software problem with the Solar Alpha Rotary Joint (SARJ), which rotates the arrays to follow the Sun, delayed that to the following day. During that day's EVA, the mission's second, MacLean and NASA astronaut Dan Burbank worked on activating the SARJ, losing a bolt in the process. The 73.2m-wide array was fully unfolded at 14:44GMT on 14 September. The array will not provide power to the ISS until further work is carried out during Shuttle Discovery's STS-116 mission in December.

STS-115 was the 116th Shuttle flight and the 19th mission to visit the ISS. Atlantis has now flown 27 times and made six trips to the station. The landing was the 21st night landing for a Shuttle and the 15th night landing at KSC.