Atlantis takes off on final mission

The space shuttle Atlantis blasted off on schedule from the Kennedy Space Center in Florida on its final flight Friday at 2:20 p.m. ET.

Two minutes after liftoff, the shuttle's twin solid rocket boosters burned out and separated, falling towards the Atlantic Ocean.

Atlantis is bound for the International Space Station with a crew of six and a load of supplies. Much of it is crammed inside a Russian-built module that will be attached permanently to the orbiting lab complex using the robotic space arm Canadarm2, Canada's key contribution to the space station.

The Russian module will provide additional storage space and a new docking port for the Soyuz and Progress spacecraft. Atlantis astronauts will venture out on three spacewalks, plugging in fresh batteries and tacking on a spare antenna.

The mission expected to last 12 days includes a number of Canadian experiments. Hypersole, for example, led by Ontario's University of Guelph and the Canadian Space Agency, will measure the sensitivity of skin on the soles of the feet of astronauts both before and after the flight.

Researchers hope the experiment will allow them to better understand the relationship between the sense of touch and balance control, eventually leading to treatment for people with balance problems.

This mission is the last for Atlantis, as NASA is retiring its three shuttles at the end of this year. After this flight, only two will be left.

Museums want to display retired shuttle

But Atlantis won't be immediately shipped to a museum when the flight is over. There are reportedly 20 museums vying for the privilege of displaying one of the three shuttles that NASA plans to retire Discovery, Endeavour and Atlantis.

NASA will hang on to Atlantis for awhile, prepping it for a potential rescue mission for NASA's last shuttle flight. That final trip, by Endeavour, is scheduled for November at the earliest. Discovery is supposed to make its last trip in September.

Like Discovery and Endeavour, Atlantis is a spaceplane that is part rocket and part aircraft, and designed to carry crews and payloads into the Earth's orbit.

Construction on Atlantis began in March 1980, and thanks to lessons learned in the construction of the shuttles Enterprise, Columbia and Challenger, it was completed in half the time it took to build the Columbia space shuttle.

Weighing in at 68,635 kilograms (151,315 pounds) when it rolled out of the assembly plant in Palmdale, Calif., Atlantis was nearly 3.5 tonnes lighter than Columbia.

10 missions over 4 years

Atlantis's maiden voyage was on Oct. 3, 1985, with a classified payload for the U.S. Department of Defence. It flew only two missions before being temporarily grounded after the 1986 space shuttle Challenger disaster, during which the shuttle fell apart mere seconds into its flight, killing all seven crew members.

Two years later, Atlantis was up and running again and flew 10 missions between 1988 and 1992. During two flights in 1989, Atlantis delivered into orbit the planetary probes Magellan, which wentto Venus, and Galileo, which wentto Jupiter. In 1991, it deployed the Compton Gamma Ray Observatory.

In 1995, Atlantis began a series of seven flights to the Russian space station Mir. When linked, Atlantis and Mir together formed the largest spacecraft in orbit at the time. Canadian astronaut Chris Hadfield was on that 1995 mission, becoming the first Canadian to operate the Canadarm.

The missions to Mir included the first on-orbit U.S. crew exchanges, now a common occurrence on the International Space Station, an orbiting science lab built by 16 countries, including Canada. On its fourth docking mission, Atlantis ferried astronaut Shannon Lucid back to Earth after her record-setting 188 days in orbit aboard Mir.

Atlantis's most recent missions have involved delivering components to the International Space Station.