And then there were two.

The Space Shuttle Endeavour prepares for its final mission today, with the rollout-moving the space shuttle from the Vehicle Assembly Building to the launch pad -- scheduled for 8 p.m. Eastern Time. The actual launch will be on April 19, the 134th and penultimate shuttle flight. The last shuttle to go into orbit will be the Atlantis, in June.

On this flight the shuttle will bring the Alpha Magnetic Spectrometer (AMS) and spare parts including two S-band communications antennas, a high-pressure gas tank, spare parts for the International Space Station's robotic arm and micrometeoroid debris shields. This will be the 36th shuttle mission to the ISS, and the mission will last 14 days.

The crew members are Commander Mark Kelly, pilot Gregory H. Johnson and mission specialists Michael Fincke, Greg Chamitoff, Andrew Feustel and European Space Agency astronaut Roberto Vittori.

Endeavour is the last of the Space Shuttle fleet to be built. It was originally a replacement for the Challenger, which was destroyed in an accident in 1986. The spacecraft is named for the HMS Endeavour, the ship of Captain James Cook on his first voyage.

Like the other shuttles, Endeavour will be decommissioned and sent to a museum, though which one has not been finalized yet.