"The countdown to liftoff of space shuttle Atlantis on its STS-132 mission officially has started. Countdown clocks at NASA's Kennedy Space Center in Florida were activated at 4 p.m. EDT, ticking backward from the T-43 hour mark."
Launch Countdown Under Way for STS-132
Launch is expected on Friday, with just two missions after that remaining, for the space shuttle before retirement.*
Watch the build up and launch on Friday, on NASA TV.
*Although after retirement, a shuttle will remain ready for lift-off for a possible rescue mission for the ISS crew, if needed...