NBC News
With a huge roar Space Shuttle Discovery lifted off on an historic mission that is expected to include two weeks full of firsts.
When Discovery docks with the International Space Station it will be the first time a female shuttle commander is welcomed by a female commander of the ISS.
"We hope that people seeing us together as we shake hands across the hatch of two fabulous and impressive space vehicles, that there is no limit to the jobs that you can have," said Shuttle Commander Pam Melroy.
There will be plenty of jobs for the crew on what's being called the most difficult mission ever.
In a record tying five spacewalks astronauts will attach the Harmony Module, a key component for upcoming European and Japanese sections.
They will also relocate a 17-and-a-half ton solar array, an unprecedented job being compared to moving a three story house.
Discovery's liftoff was not without controversy.
Independent safety experts and some NASA engineers expressed concern over small cracks on the wing.
Ultimately mission managers decided to fly.
"We fly every time without having solved every one of our problems," explained NASA's Wayne Hale.
