As the space shuttle program approaches its scheduled termination in 2010, efforts to complete the International Space Station (ISS) are increasing. STS-118 mission will deliver and assemble four main components to the ISS: starboard S5 truss segment (weighting close to 2 tons with a length of close to 14 meters), external stowage and a replacement control moment gyroscope (CMG), and a spacehab (logistics single module).

The mission, which will take place over a period of 11-14 days (depending on NASA's decision to extend it), will include several Extravehicular Activities (EVAs) where the astronauts will install the different parts they brought with them from Earth. 

Endeavour carries a crew of seven astronauts, including one Canadian and two women. One of the two women is Barbara Morgan who trained as the backup to Christa McAuliffe, NASA's Teacher in Space candidate in 1986, who was killed in the space shuttle Challenger accident. Morgan will become the first teacher in space on STS-118, and will carry with her millions of basil seeds which she will carry back to earth and give to her students upon her return. 

STS-118 will mark the debut of an upgraded power-distribution module called the Station-Shuttle Power Transfer System (SSPTS). SSPTS will allow the Endeavour to operate from the ISS power supply, converting up to eight kilowatts (8 kW) of electrical power from the 120-volts direct-current (120VDC) ISS main voltage to the 28VDC system used by the shuttle orbiter.

TFOT covered all the recent shuttle lunches including STS-121 on July 4^th, 2006, STS-115 on September 9^th, 2006 and STS-116 on December 9^th, 2006 and STS-117 on June 8^th, 2007. 

More information on STS-118 can be found on NASA's website, including more images and videos of the launch.