CAPE CANAVERAL, Fla. — NASA officials say they’re pleased that space shuttle Endeavour’s final launch is expected to attract more than a half-million visitors Friday, including President Barack Obama.

They’re also thrilled that the commander’s wife, Rep. Gabrielle Giffords, will be on hand for the liftoff.

The only downside is all the traffic tie-ups expected before and after the planned 3:47 p.m. launch. Good launch weather is forecast, and the countdown is going well.

Giffords left Houston for Cape Canaveral late this morning. Her husband, Mark Kelly, is leading the six-man crew that will fly Endeavour one last time.

Giffords was shot in the head Jan. 8 in Tucson, Ariz., and has been undergoing rehabilitation in Houston.